Abstract Book

26th CRSI-National Symposium in Chemistry CRSI-NSC-26 February 07-09, 2020 Abstract Book

Jointly Organized by Department of Chemistry VIT Vellore, CRSI, & RSC, UK Contents

Welcome

Organizing Committee

Message from Founder President, CRSI

Message from Founder Chancellor, VIT

Message from Pro Vice Chancellor, VIT

Message from President, CRSI

Message from Dean, School of Advance Science

Acknowledgements

Program

Abstracts

President’s Lecture

Animesh Chakravorty Endowment Lecture

CRSI Medal Lecture

C. N. R. Rao National Prize for Chemical Research

CRSI Honorary Fellowship Lecture

C. N. R. Rao Award Lecture

Silver Medal Lecture

Mizushima - Raman Lecture

Third Charusita Chakravarty Memorial Lecture

Lifetime Achievement Award Lecture

Bronze Medal Lectures

Invited Lectures

Abstracts Posters

Welcome Message from Organizers

On behalf of organizing committee of the 26th National Symposium in Chemistry (NSC) and 14th Royal Society of Chemistry Joint Symposium under the auspices of the Chemical Research Society of India (CRSI), we are delighted to welcome you to the symposium and to the Vellore Institute of Technology Vellore.

The 26th CRSI-NSC meeting is attended by a large number of scientists, academicians and students from universities and academic/research institutions spread across the length and breadth of India. The meeting is attended by nearly 200 registered participants. The symposium has 34 lectures that include CRSI medal lectures, special lectures. More than 130 posters will be presented by faculty and students.

The Royal Society of Chemistry, UK has been partnering with CRSI in organizing a one day symposium, along with the CRSI National Symposium over the years. This year also, there will be a CRSI-RSC symposium on February 6, 2020, preceding the CRSI National Symposium at Vellore.

The main purpose of the NSC meeting is to create a platform where scientists, teachers and students across the country come together and discuss recent developments in the area of chemical sciences. Meetings like this that encompass all the domains of chemistry can help to build long lasting collaborative endeavours in the frontier areas of chemistry and its allied disciplines.

We thank the CRSI governing body and council members for their valuable inputs and continuous encouragement. The credit of the success of this meeting shall go all the faculty members and students of the Department of Chemistry, VIT Vellore. We acknowledge our gratitude to The Chancellor, Vice-Presidents, Asst. Vice-President, Vice-Chancellor, Pro-VC, Registrar, and the Dean of SAS for their support. We thank the sponsors for their financial aid and support. Last but not the least, we thank all the participants who have travelled far to attend the symposium. We wish you a great time at VIT Vellore during the symposium

Sincerely

R Vijayaraghavan, Kaushik Chanda and Priyankar Paira (on behalf of the Organizing Team)

Organizing Committee Department of Chemistry, VIT Vellore

S. No. Committee Members

1 Dean Dr. A. Mary Saral

2 HoD Dr. S.L. Manju

3 Convener Dr. R. Vijayaraghavan

Dr. Kaushik Chanda 4 Organizing Secretaries Dr. Priyankar Paira

5 Registration Dr. I.V. Asha Rani

Dr. K. Thenmozhi 6 Reception

7 Transport Dr. K.K. Cheralathan

8 Printing Dr. A. Anand Prabu Dr. Madhvesh Pathak 9 Guest Care Dr. Tamas Panda 10 VIP Guest Care Dr. S. Sasikumar

Mementos/Banners/ Tags/Abstract Dr. Kaushik Chanda 11 Book/Pen Drive Dr. Anisha Thomas

Dr. Kannadasan i/c Dr. K.K. Cheralathan 12 Food Committee Dr. K.R. Ethiraj Dr. G. Thirumanavelan Dr. K. Thirumoorthy

13 Men's Hostel Dr. M. Shiva Shankar

14 Ladies Hostel Dr. Barnali Maiti

15 Cultural Dr. G. Madhumitha

Dr. R. Vijayaraghavan (i/c) Dr. Kaushik Chanda 16 Finance Dr. Priyankar Paira Dr. Mausumi Goswami

17 Accounts Dr. R. Vijayaraghavan

Dr. V. Vijayakumar i/c 18 Poster Committee Dr. S. Rajasekar Reddy Dr. Sovan Roy

Dr. G. Buvaneswari 19 Poster Evaluation Dr. V. Vijayakumar

20 Hall Arrangement Dr. Pundlik Rambhau Bhagat

21 Website Dr. R. Vijayaraghavan

22 Pre Conference Dr. U. Vijayalakshmi

Abstract Compilation/Segregation/ 23 Dr. Priyankar Paira Data Extraction

Formatting/Abstract Book 24 Dr. Kaushik Chanda Making/RSC&CRSI

Writing to all speakers/Council 25 Dr. R.Vijayaraghavan Members/RSC Delegates

Message from Professor C. N. R. Rao

Founder President of CRSI

Message from Dr G. Viswanathan

Founder Chancellor, VIT

Message from Dr S. Narayanan

Pro Vice Chancellor, VIT

Message from Professor N. Sathyamurthy

President of CRSI

Message from the President, Chemical Research Society of India (CRSI)

I am delighted that the Division of Chemical Sciences at the Vellore Institute of Technology (VIT), Vellore has come forward to host the 26th CRSI National Symposium in Chemistry during February 7-9, 2020.

This is the first time that the CRSI National Symposium is hosted by a private university. We are particularly pleased that VIT, an Institution of Eminence is hosting the event.

On behalf of CRSI and on my own, I would like to express our gratitude to Professor R Vijayaraghavan and his colleagues for organizing the symposium consisting of several bronze, silver, gold and other CRSI medal lectures and invited lectures by different awardees and a special symposium on Materials. I could see that it is going to be an exciting event.

We are pleased that Chemistry – An Asian Journal has brought out a special issue to celebrate 20 years of CRSI, founded by Professor C N R Rao. It will be released at the Symposium and it showcases the chemistry research in India. It is worth mentioning here that India is No. 3 (China (1), USA (2)) in terms of total number of publications in the world now.

With an ever increasing life membership and an increasing participation by young research scholars, each CRSI National Symposium reflects truly the state of chemistry in the country. There is a number of prizes to be won by young chemists for their work presented in the form of posters.

Looking forward to a fruitful meeting in VIT Vellore,

Yours sincerely,

N. Sathyamurthy

President, Chemical Research Society of India, Bengaluru

Message from Professor A. Mary Saral

Dean, SAS

Acknowledgements

26th CRSI National Symposium in Chemistry (NSC-26) Programme Friday, 7 February 2020, Venue- Ambedkar Auditorium, Technology Tower , Ground Floor , 9.30 to 18.05

08:30 - 09:30 Registration SESSION I: INAUGURATION AND PRESIDENTIAL ADDRESS 09:30– 10:30 10:30 – 11:00 HIGH TEA SESSION II: SPECIAL LECTURES CHAIRPERSON: V. Krishnan 11:00 – 11:45 Animesh Chakravorty Endowment Lecture A. S. Borovik, University of California-Irvine, USA Molecular Complexity and Inorganic Chemistry: Utilizing Non-Covalent Interactions to Control Function

11:45 – 12:15 CRSI Medal Lecture Arun Yethiraj, University of Wisconsin-Madison, USA Polymers in ionic liquids

12:15 – 12:45 C. N. R. Rao National Prize for Chemical Research G. U. Kulkarni, JNCASR, Bangalore Au Au decahedra: Unusual nucleus for unconventional lattices 12:45 – 16:00 LUNCH AND POSTER SESSION I, CS hall Posters No. 1 to 65 P132-139 14:00 – 15:00 COUNCIL MEETING (Members only), Board Room, MGR Block 15:30 – 16:00 TEA/COFFEE SESSION III: MEDAL AND SPECIAL LECTURES CHAIRPERSON: S. Chandrasekaran 16:00 – 16:45 CRSI Honorary Fellowship Lecture Sunney I. Chan, Academia Sinica, Taiwan Taming Methane: A catalyst for Efficient and Selective Methane Oxidation under Ambient Conditions

16:45 – 17:05 Bronze Medal Lecture Ranjani Viswanatha, JNCASR, Bangalore Mn emission: Energy transfer or Charge transfer

17:05 – 17:25 Bronze Medal Lecture Manmohan Kapur, IISER, Bhopal Transition-metal-catalyzed Distal and Remote Functionalizations

17:25 – 17:45 Bronze Medal Lecture Rajakumar Balla, IIT Madras Measurement of absorption cross-sections and kinetics of radicals relevant to the Earth’s atmosphere using Cavity Ring Down Spectroscopy

17:45 – 18:05 Bronze Medal Lecture

S. G. Srivatsan, IISER, Pune Probing Mood (Structure) Swings of Non-Canonical Nucleic Acid Motifs

18:15 – 19:15 CULTURAL PROGRAM, Anna Auditorium 19:30 – 21:30 DINNER, Foodys Saturday, 8 February 2020, Venue: Gallery -2, Tech, Tower, 2nd Floor 9.30 to 18.15

SESSION IV: SPECIAL/MEDAL LECTURES CHAIRPERSON: Sourav Pal

09:30 – 10:15 C. N. R. Rao Award Lecture

Richard Catlow, University College London, UK Modeling, Synchroton Radiation and Neutron Scattering Studies of Structure, Dynamics and Reactivity in Catalytic Systems 10:15 - 10:45 Silver Medal Lecture

K. Vijayamohanan Pillai, IISER, Tirupati Phosphorene Quantum Dots: Electrochemical Preparation, Doping and Possible Applications 10:45 – 11:15 TEA/COFFEE

SESSION V: MEDAL LECTURES CHAIRPERSON: R. N. Mukherjee 11.15 – 12.00 Mizushima - Raman Lecture

Tahei Tahara, Riken, Wako, Japan Time-Domain Raman Spectroscopy and Its Application to Ultrafast Photochemical / Photobiological Reactions

12.00 – 12.30 CRSI Medal Lecture

Jagadese J. Vittal, National University of Singapore, Singapore My Journey with Crystals under UV Light and beyond

12.30 – 13.00 Third Charusita Chakravarty Memorial Lecture

Srabani Taraphder, IIT Kharagpur Reaction Coordinate, Free Energy and Kinetics in an Enzyme Catalysed Proton Transfer Reaction

13:00 – 16:00 LUNCH AND POSTER SESSION II Venue – Foodys Poster No. 66-131, P140

15:30 – 16:00 TEA/COFFEE

SESSION VI: MEDAL LECTURES CHAIRPERSON: K. P. Kaliappan

16:00– 16:30 Silver Medal Lecture

Subrata Ghosh, IACS, Kolkata

Natural Products Synthesis – Some Fascinating Aspects

16:30 – 16:50 Bronze Medal Lecture

Mahesh Hariharan, IISER, Trivandrum Ultrafast Excited State Dynamics of Twisted Aromatics

16:50 – 17:10 Bronze Medal Lecture

Ashwani Kumar Tiwari, IISER, Kolkata Effects of Mode-Mode Coupling on the Dissociation Dynamics of H2O and CH4 on Metal Surfaces SESSION VII: LIFETIME ACHIEVEMENT AWARD LECTURE CHAIRPERSON: N. Sathyamurthy

17:10 – 18.00 T. Ramasami, CSIR-CLRI Chennai A Story of an evolution of a chemist 18:00 – 19:15 General Body Meeting and Presentation of Medals/Awards 19:30 – 21:30 CONFERENCE DINNER, Foodys & Greeno

Sunday, 9 February 2020, Gallery -2,Tech, Tower, 2nd Floor, 9.30 to 13.15

SESSION VIII: MEDAL LECTURES CHAIRPERSON: G. Sekar 09:30 – 09:50 Bronze Medal Lecture E. Balaraman, IISER, Tirupati Non-noble metal catalysis: Applications in dehydrogenation and related reactions

09:50 – 10:10 Bronze Medal Lecture Gouriprasanna Roy, IIT Tirupati Biomimetic Studies to understand the mechanism of Hg−C bond protonolysis by mercury-resistant Organomercurial Lyase MerB

10:10 – 10:30 Bronze Medal Lecture Santanu Kumar Pal, IISER, Mohali Highly Efficient Ambipolar Charge Transport in Semiconducting Discotic Liquid Crystals

10:30 – 11:00 TEA/COFFEE SESSION IX: THEMATIC MINI-SYMPOSIUM CHAIRPERSON: S. Muthusamy 11:00 – 11:30 Invited Lecture R. Vijayaraghavan, VIT, Vellore Development of Sensors & Proto type set up for Fruit Ripening Application

11:30 – 11:50 Invited Lecture Hongdoo Kim, Adjunct Faculty, VIT, Vellore Hybrid Piezocapacitive / Piezoelectric Sensor Based on Electro spun

Nanowire Web

11:50 – 12:10 Invited Lecture A. Senthilkumar, VIT, Vellore Redox Active Organic Molecule Functionalized Carbon Nanomaterials for Elegant Electrochemical Immuno-sensing of Shrimp-Virus

12:10 – 12:25 Invited Lecture S. Senthilkumar, VIT, Vellore Rationally Designed Ionic Liquids for Electrochemical Sensing

12:25 – 12:40 Invited Lecture S. K. Ashok Kumar, VIT, Vellore New Thorium (IV) Selective Sensors

12:40 – 12:55 Invited Lecture S. Sarveswari, VIT, Vellore Organic Small Molecules as Chemosensors 12:55 – 13:15 Concluding Remarks

13:15 – 14:15 LUNCH AND DEPARTURE, Basket ball court, Opposite to Tech Tower

Abstracts

26th CRSI National Symposium in Chemistry

President’s Lecture

Narayanasami Sathyamurthy

Honoraray Professor Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore Jakur, Bemgaluru560064. E-mail: [email protected]

Dr. N. Sathyamurthy received his Ph.D from Oklahoma State University, USA. After working as post doctoral fellow with Professor J.C. Polanyi at the university of Toronto Canada, he joined IIT Kanpur as lecturer in the department of Chemistry where he roles to the rank of an institute professor. He was the former director of IISER Mohali. He has authored more than 200 research papers in national and international journals. He has received several awards and recognition in the country.

President’s Lecture

Chemical Oscillations and Synchronous Pulsed Flowering in Passiflora incarnata

N. Sathyamurthy*

Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru.

In addition to the familiar Belousov-Zhabotinskii oscillatory chemical reactions, there are several complex chemical reactions that exhibit spatial and temporal oscillations. Our recent discovery of ―synchronous pulsed flowering‖ in passion flower suggests underlying activating and inhibiting factors that are responsible for temporal oscillations in flowering as well as spatial patterns in a flower. Spectrochemical investigations of the anthocyanins in passion flower bring forth the challenges involved in studying natural products chemistry.

Illustration of synchronous pulsed flowering in Passiflora incarnata in the year 2017.

References:

1 Goyal, S.; Reji, R.; Tripathi, S. S.; Sathyamurthy, N. Current Science, 2019, 117, 1211-1216.

26th CRSI National Symposium in Chemistry

Animesh Chakravorty Endowment Lecture

A.S. Borovik

Professor Department of Chemistry University of California Irvine, California 92697 USA Email: [email protected]

A. S. Borovik was raised in Chicago and received his B.S. degree in Chemistry with Honors from Humboldt State University. As an undergraduate student he did research at Oregon State University as an NSF Summer Fellow and at Woods Hole Oceanographic Institution as a WHOI Fellow. Both research experiences involved using nuclear chemistry to trace metal ions in the environment. He obtained his Ph.D. in Chemistry at the University of North Carolina-Chapel Hill under Tom Sorrell where he developed photophysical models for the active site of copper proteins. As an NIH postdoctoral fellow with Larry Que at the University of Minnesota, he designed synthetic complexes that replicated the properties of dinuclear iron centers in proteins. Upon completion of his postdoctoral fellowship, Professor Borovik joined the faculty at Ithaca College where he taught chemistry and mentored 6 undergraduate research students for two years. He then moved to the University of California-Berkeley as a postdoctoral associate with Ken Raymond, working on stereonostic coordination chemistry. From there, he joined the Chemistry Department at Kansas State University where he began a broad program on the effects of the secondary coordination sphere on metal ions. After 3 years, he moved his research group to the University of Kansas, continuing research on the development of metal complexes and hybrid materials with unique structural and functional properties. In 2006, Professor Borovik and his research group moved to the University of California- Irvine, expanding his approach to now include designing artificial metalloproteins. Professor Borovik has won several teaching and research awards that include a 2017 MERIT Award from the NIH and the 2018 National Cotton Award in Synthetic Inorganic Chemistry from the American Chemical Society.

Animesh Chakravorty Endowment Lecture

Molecular Complexity and Inorganic Chemistry: Utilizing Non-Covalent Interactions to Control Function

A.S. Borovik*

Department of Chemistry University of California Irvine, California 92697 USA

Location matters…no compound operates in isolation without interacting with its local environment. Metalloproteins are example systems whose active sites contain intricate structures that aid the performance of specific functions with high selectivities and efficiencies. The complexity of these systems complicates the study of their function and the understanding of the properties that give rise to their reactivity. One approach that has contributed to the current level of knowledge is the study of synthetic constructs that mimic one or more aspects of the native metalloproteins. These systems allow for analysis of individual components of structure and how they affect function. We are thus able to establish structure-function correlations that are necessary for evaluating mechanisms. Using key architectural features from active sites of metalloproteins as inspiration, my group has developed design approaches to prepare systems that regulate local environments around a metal center. These systems are used to study the activation of small molecules (e.g., O2 and H2O) that are essential in maintenance of human health. This presentation will highlight our molecular designs from small synthetic complexes to the use of larger, more diverse protein hosts.

26th CRSI National Symposium in Chemistry

CRSI Medal Lecture s

Arun Yethiraj

Professor Department of Chemistry University of Wisconsi-Madison USA Email: [email protected]

Personnel Web page https://yethiraj.chem.wisc.edu/

CRSI Medal Lectures

Polymers in ionic liquids

Arun Yethiraj*

Professor Department of Chemistry University of Wisconsin-Madison USA

Ionic liquids have generated considerable excitement for their varied potential applications and their interesting physical properties. The viability of ionic liquids (ILs) in materials applications is limited by their lack of mechanical integrity, which may be provided by mixing them with a polymeric material. Recent experiments on polymers in ILs have unearthed a wealth of interesting phenomena that raise fundamental questions. This talk focuses on computational studies of PEO in imidazolium ILs. We develop a physically motivated first principles force field for PEO and [BMIM] [BF4]; this force field is in quantitative agreement with experiment with no adjustable parameters. Based on the same quantum calculations we develop a hierarchy of united atom models with decreasing resolution and increasing computational efficiency. Microsecond simulations are required to obtain converged properties of the polymer, which displays a combination of ring-like and extended conformations. The simulations show the existence of a lower critical solution temperature which arises from conformational restrictions on the polymer molecules at low temperatures.

Jagadese J Vittal

Professor Department of Chemistry National University of Singapore Singapore Email: [email protected]

JJ Vittal received his BSc from the University of Madras in 1975, MSc from Madurai University in 1977 and PhD from Indian Institute of Science, Bangalore in 1982. After postdoctoral research at the University of Western Ontario, Canada, he managed the X-ray facility for a few years. He then moved to Singapore in 1997 where he is currently Professor in the Department of Chemistry, National University of Singapore. He held a World Class University Chair Professorship at the Gyeongsang National University, Jinju, South Korea (2009-2013). His major research interests include design & synthesis of coordination polymers & metal-organic frameworks, solid-state supramolecular structural transformations, solid state photochemical reactivity, single molecular precursor routes to various metal chalcogenides, oxides bulk materials, films and nanocrystals, and battery materials. JJ published about 500 research papers, reviews and book chapters with ~22000 citations and h-index of 72. He co-authored ‗Crystal Engineering – A Textbook‘ with G.R. Desiraju and A. Ramanan. He also co-edited two books on crystal engineering with E.R.T. Tiekink. He is a Fellow of Royal Society of Chemistry and Singapore National Institute of Chemistry. He is an editorial board members of several journals including Crystal Growth & Design and Scientific Reports. He won several awards including Outstanding Chemist Award (2014), CRISP Award (2013), Outstanding Research Award (2011) and Best Scientist Award (2007). JJ has been highlighted in Angewandte Author Profile (2014). He is founder, chair and Organizing Committee member of Singapore National Crystal Growing Challenge (1997-2014) to promote science through the art of growing crystals. He is an international committee member of Worldwide IUCr Crystal Growing Competition for School Children since 2014.

CRSI Medal Lectures

My Journey with Crystals under UV Light and beyond

JJ Vittal,

Professor Department of Chemistry National University of Singapore,SINGAPORE 117543.

The physical and chemical properties of the solids are directly related to their crystal structures. The crystal engineering tools can be used to modify and fine-tune these properties. It is possible to design organic crystals, coordination polymers and metal-organic framework materials with desired physical properties like solubility, crystal bending, guest and gas sorption, storage, separation and transportation, ion exchange, catalysis, magnetism (magnetic ordering, spin crossover), conductivity, optics (multi-photon upconversion, luminescence and sensing, birefringence), negative thermal expansion and processability. As more and more exotic new crystals are made, unexpected, unusual and unpredictable properties have been discovered. In our laboratory we have encountered a number of interesting properties such as structural transformations due to solvent exchange, change of composition and dimensionality due to grinding, unexpected photoreactivity of organic crystals and transition metal complexes and centrosymmetric MOFs showing second-order non-linear optical properties. Mechanically responsive materials change their shape and size or move in space by light, thermal, pressure or chemical energy. Of these, dynamic molecular crystals undergo various movements like curling, crawling, jumping, leaping, hopping, popping, splitting, wiggling, and exploding, when exposed to heat (thermosalient effect) or light (photosalient effect). These photo- dynamic and thermal-dynamic crystals create new ways of transforming light and heat energy into mechanical work. These effects are similar to popping of mustard seeds on hot oil or corn on hot surfaces. Recently we have also observed such violent popping of single crystals of several metal complexes during the [2+2] cycloaddition reaction under UV light showing the photosalient behavior. In this talk some of these interesting and unusual physical and chemical properties of crystals will be presented.

References:

1. Vittal, J.J.; Quah, H.S. Coord. Chem. Rev. 2017, 342, 1-18 2. Vittal, J.J.; Quah, H.S. Dalton Trans. 2017, 46, 7120-7140 3. Liu, M.; Quah, H.S.; Wen, S.; Wang, J. Kumar, P.S.; Eda, G.; Vittal, J.J.; Ji, W. J. Mater. Chem. C 2017, 5, 2936-2941 4. Medishetty, R.; Park, I.H.; Lee, S.S.; Vittal, J.J. Chem. Commun. 2016, 51, 3989-4001. 5. Kole, G.K.; Vittal, J.J. Chem. Soc. Rev. 2013, 42, 1755-1775

26th CRSI National Symposium in Chemistry

C.N. R. Rao National Prize for Chemical Research Lecture

Giridhar U. Kulkarni

Director and Professor Centre for Nano and Soft Matter Sciences P.B.No. 1329, Prof. U.R. Rao Road Jalahalli - Bengaluru, Karnataka 560 013 - India. Email: [email protected]

G. U. Kulkarni is a Professor, Chemistry and Physics of Materials Unit, JNCASR and Director at CeNS, Bangalore. He received his PhD at Indian Institute of Science in 1992 and has held visiting/adjunct positions at Cardiff, Tokyo, TASC-INFM, Trieste; Scuola Normale Superiore, Pisa; Purdue etc. His present research interests are focused on new strategies in synthesis of nanomaterials, nanopatterning and nanodevice fabrication including of molecular systems. His recipes emphasize the importance of simple design, near ambient working conditions, solution based processing as well as low cost instrumentation. His group strives to translate nanoresearch finding into affordable technology.

C.N. R. Rao National Prize for Chemical Research Lecture

Au decahedra: Unusual nucleus for unconventional lattices

Giridhar U. Kulkarni

Professor Centre for Nano and Soft Matter Sciences Bangalore, India

Cubic lattice structure preferred by noble metals (e.g., Au, Ag, Pd and Pt) is thermodynamically highly stable. Lower symmetry crystal structures are not known to stabilize relative to the face-centered cubic (fcc) bulk even at high pressures. Observing a structural transformation in these metals is therefore fundamentally exciting and can be possibly useful in tuning their otherwise noble behavior. Recent explorations in this direction have focused on nanocrystals, as the energy needed for lattice distortion is relatively low when the size is only a few nanometers. Inducing lattice strain at larger length scales to cause structural transformation in the crystallite is indeed a herculean task. The same has been achieved by us by stabilizing a decahedral nanocrystal via a simple synthetic method involving a careful thermolysis of a metal-organic precursor in air. The presentation will describe the synthesis of Au decahedra nuclei and the growth aspects.The results obtained using in-housefacilities, on the morphology of the microcrystals, the unusual lattice forms and their phase transitions, chemical reactivity etc. will be presented. Further, the insights obtainedusing nanofocus synchrotron X-raybeamline on individual crystalliteson the distribution of the various phases will be described.

References:

1. Mettala, G.; Radha, B.; Singh, D.; Kumar G. V. P.; Kulkarni, G.U. Sci. Rep., 2013, 3, 1793. 2. Mettela, G.; Bhogra, M.; Waghmare U.V.; Kulkarni, G.U. J.Am.Chem.Soc, 2015, 137, 3024. 3. G. Mettela and G. U. Kulkarni, Nano Research,2015, 9, 2925. 4. G. Mettela and G. U. Kulkarni, Cryst. Eng. Comm., 2015, 17, 9459. 5. G. Mettela, N. Mammen, J. Joardar, S. Narasimhan and G. U. Kulkarni, Nano Research, 2017, 10, 2271. 6. G. Mettela, S. A. Yesudas, A. Shukla, C. Bellin, V. Svitlyk, M. Mezouar, C. Narayana and G. U. Kulkarni, Chem. Mater., 2017, 29, 1485. 7. G. Mettela, S. Kouser, C. Sow, S. T. Pantelides and G. U. Kulkarni, Angew. Chem. Int. Ed., 2018, 57, 9018.

26th CRSI National Symposium in Chemistry

CRSI Honorary Fellowship Lecture

Sunney I. Chan

Institute of Chemistry, Academia Sinica, Taipei Department of Chemistry, National Taiwan University, Taipei E-mail: [email protected]

B.S. (1957) and Ph.D. (1960), University of California, Berkeley.；National Science Foundation Postdoctoral Fellow, 1960-1961, Harvard University.；Assistant Professor, 1961-1963, University of California, Riverside.；Assistant Professor, 1963-1964; Associate Professor, 1964-68; Professor, 1968-1992; George Grant Hoag Professor of Biophysical Chemistry, 1992-2001; Hoag Professor, Emeritus, 2002-, California Institute of Technology.；Honorary Professor, 1996-2015, Chinese University of Hong Kong. ；Chair Distinguished Professor of Chemistry, 2007-2010; Distinguished Research Chair Professor, 2010-2016, National Taiwan University.；Honorary Chair Professor, 2012-14, National Ping Tung University of Education.；Chair Professor of Bioinorganic Chemistry, 2013-16, National Chung Hsing University. ；Distinguished Research Fellow and Director, 1997-1999; Distinguished Research Fellow, 1999-2011; Distinguished Visiting Fellow, 2011-15, Institute of Chemistry, Academia Sinica.；Vice President, 1999-2003, Academia Sinica.；Director, National Research Program of Genomic Medicine, 2001-03, National Science Council, Republic of China.；

CRSI Honorary Fellowship Lecture

Taming Methane: A Catalyst for Efficient and Selective Methane Oxidation under Ambient Conditions

Sunney I. Chan

Institute of Chemistry, Academia Sinica, Taipei Department of Chemistry, National Taiwan University, Taipei ROC

1 The conversion of methane (CH4) into methanol (CH3OH) is extremely difficult chemistry.

Methanotrophs metabolize CH4 as their sole source of carbon and energy, converting substantial amounts of the CH4 produced by methanogenic bacteria into CH3OH in the presence of molecular oxygen (O2). Over the past several decades, scientists have purified and studied in depth two enzymes responsible for this chemistry.1 Based on our fundamental understanding of how the particulate methane monooxygenase (pMMO) works, we have recently developed a biomimetic 2-4 catalyst capable of efficient and selective CH4 oxidation under ambient conditions. The catalytic I I I system consists of a Cu Cu Cu tricopper cluster complex activated by O2 to produce a harnessed oxene, which is rapidly inserted across one of the C—H bonds of the CH4 molecule in the transition state when the substrate is bound to the hydrophobic pocket built into design of the tricopper complex. Catalytic turnover is sustained by regenerating the functional catalyst with a molecule of

H2O2 for each CH4 molecule oxidized. The catalytic system can operate either as a homogeneous catalyst in a solvent2-3or reformulated as a quasi-heterogeneous catalyst by immobilizing the complex within the nanochannels of mesoporous silica nanoparticles.4 The catalytic efficiency of the quasi- heterogeneous catalyst is unprecedented. Progress has also been made toward developing this catalytic system to accomplish the conversion of the light alkanes in natural gas into their corresponding oxygenated products.5 The development of this catalytic system further for the control of low pressure natural gas seeps and CH4 emissions from various human activities into the atmosphere is under consideration.

References:

1. Wang, V. C.-C.; Maji, S.; Chen, P. P.-Y.; Lee, H. K.; Chan, S. I. Chem. Rev. 2017, 117, 8574−8621. 2. Chan, S. I.; Lu, Y.-J.; Nagababu, P.; Maji, S.; Hung, M.-C.; Lee, M. M.; Hsu, I.-J,; Minh, P. D.; Lai, J. C.-H.; Ng, K. Y.; Ramalingam, S.; Yu, S. S.-F.; Chan, M. K. Angew Chem Int Ed 2013, 52, 3731–3735. 3. Nagababu, P.; Yu, S. S.-F.; Maji, S.; Ramu, R.; Chan, S. I. Catal Sci Technol 2014, 4, 930– 935. 4. Liu, C.-C.; Mou, C.-Y.; Yu, S. S.-F.; Chan, S. I. Energy Environ Sci 2016, 9, 1361–1374. 5. Liu, C.-C.; Janmanchi, D.; Wen, D.-R.; Oung J.-N.; Mou, C.-Y.; Yu, S. S.-F.; Chan, S. I. ACS Sustainable Chem Eng. 2018, 6, 5431–5440.

26th CRSI National Symposium in Chemistry

C.N.R. Rao Award Lecture

Richard Catlow

Department of Chemistry, University College London; School of Chemistry, Cardiff University; UK Catalysis Hub, Research Complex at Harwell, UK

Richard Arthur Catlow FRS FRSC FinstP (born 24 April 1947) is a British chemist, and professor at University College London Previously, he was Director of the Davy Faraday Research Laboratory, and Wolfson Professor of Natural Philosophy at the Royal Institution. Since 2016 he has served as the foreign secretary of the Royal Society.

C.N.R. Rao Award Lecture

Modelling, Synchroton Radiation and Neutron Scattering Studies of Structure, Dynamics, and Reactivity in Catalytic Systems

Richard Catlow

Department of Chemistry, University College London; School of Chemistry, Cardiff University; UK Catalysis Hub, Research Complex at Harwell, UK

The concerted use of synchrotron, neutron and modelling techniques has proved to be a powerful approach in probing catalytic structures and processes at the molecular level. We will illustrate the approach by recent applications to a range of systems including:

 Hydrocarbon dynamics and reactivity in microporous catalysts, where we will describe how the concerted use of modelling with neutron spectroscopy can yield unique information on molecular transport and reactivity in hydrocarbon synthesis and auto-exhaust catalysts.

 Structural and electronic properties of nano-particulate catalysts, including photocatalysts, where the focus will be on the combination of modelling with synchrotron techniques in developing detailed structural models of supported nano-particles.

 Carbon dioxide and methane activation on oxide and carbide catalysts where the focus will be on developing models for the activation mechanisms.

We will discuss how this powerful combination of techniques might be applied more widely in catalytic science.

26th CRSI National Symposium in Chemistry

Mizushina -Raman Lecture

Tahei Tahara

Chief Scientist Molecular Spectroscopy Laboratory, RIKEN, Japan. E-mail: [email protected]

Tahei Tahara graduated from the department of chemistry, the faculty of science, the University of Tokyo, in 1984, and obtained his PhD degree in 1989 from the same university. He became research associate of the University of Tokyo in 1989, and then moved to newly founded Kanagawa Academy of Science and Technology (KAST) as research associate in 1990. In 1995, he joined Institute for Molecular Science (IMS) as associate professor and started his own research group. He moved to RIKEN as Chief Scientist in 2001 and has been the Director of Molecular Spectroscopy Laboratory since then. He is also now Visiting Professor of Saitama University and Tokyo Institute of Technology. His research interests are ultrafast spectroscopy, nonlinear spectroscopy and single molecule spectroscopy of complex molecular systems. He received Award of Research Foundation for Opto- Science and Technology (1995), Morino Science Award (2000), TRVS Young Researcher Award (2001), IBM Japan Science Prize (2004), the JSPS Prize (2006), CSJ Award for Creative Work (2012), Distinguished Asian Visiting Speaker Award of University of Alberta (2013), the Commendation for Science and Technology by MEXT (Prize for Science and Technology) (2017), the Spectroscopic Society of Japan Award (2017), Distinguished Scientist Awards of the Japan Society for Molecular Science (2017), Award for Outstanding Contribution to Raman Spectroscopy (2018), TRVS Lifetime Achievement Award (2019), Mizushima-Raman Lecturer (2020). He is currently President of Japan Society for Molecular Science

Mizushina-Raman Lecture

Time-Domain Raman Spectroscopy and Its Application to Ultrafast Photochemical/Photobiological Reactions

Tahei Tahara

Molecular Spectroscopy Laboratory, RIKEN, Japan.

Since its discovery 90 years ago, Raman spectroscopy has been developing continuously, and it is now one of the most important spectroscopies which is extensively utilized in various fields of science and technology. In traditional Raman spectroscopy, the energetically-shifted inelastic light scattering (Raman scattering) is measured, and the energy shift from the excitation light provides information about the vibrational energy of the molecules. On the other hand, using an ultrashort optical pulse that has a duration shorter than the vibrational period of molecules, we can carry out time-domain Raman spectroscopy that induces coherent nuclear motion of the molecule with the impulsive stimulated Raman process and observes Raman-active vibrations directly in the time domain. In principle, the information obtainable with time-domain Raman spectroscopy is equivalent to that obtained by ordinary frequency-domain Raman spectroscopy. However, because time-domain Raman spectroscopy is performed with only femtosecond pulses, we can trace the temporal change of the molecular vibrations with a femtosecond accuracy by combining it with a femtosecond pump pulse that starts chemical reactions.1-3 In this lecture, I talk about the recent progress of our research about femtosecond time-domain Raman spectroscopy. A newly developed apparatus using 7-fs optical pulses allowed us to investigate the ultrafast dynamics of complex molecular systems such as the chromophore isomerization in photoreceptor proteins and the chemical bond formation process in molecular assemblies.4-6 We also showed the possibility of multi-dimensional time-domain Raman spectroscopy that reveals the anharmonicity of reactive excited-state potential energy surfaces of complex molecules.7 References:

1. Fujiyoshi, S; Takeuchi, S; Tahara, T. J. Phys. Chem. A, 2003, 107, 494-500. 2. Cerullo, G.; Lüer, L.; Manzoni, C.; S. Silvestri, S.; Shoshana, O.; Ruhman, S. J. Phys. Chem. A, 2003, 107, 8339-8344. 3. Takeuchi, S.; Ruhman, S.; Tsuneda, T.; Chiba, M.; Taketsugu, T.; Tahara, T. Science 2008, 322, 1073-1077. 4. Fujisawa, T; Kuramochi, H.; Hosoi, H.; Takeuchi, S.; Tahara, T. J. Am. Chem. Soc. 2016, 138, 3942-3945 (2016). 5. Kuramochi, H.; Takeuchi, S.; Yonezawa, K.; Kamikubo, H.; Kataoka, M.; Tahara, T. Nat. Chem. 2017, 9, 660-666. 6. Kuramochi, H.; Takeuchi, S.; Iwamura, M.; Nozaki, K.; Tahara, T. J. Am. Chem. Soc. 2019, 141, 19296-19303. 7. Kuramochi, H.; Takeuchi, S.; Tahara, T, Sci. Adv. 2019, 5, eaau4490 /1-7.

26th CRSI National Symposium in Chemistry

3rd Charusita Chakravarty Memorial Lecture

Srabani Taraphder

Department of Chemistry Indian Institute of Technology Kharagpur, India E-mail: [email protected]

Srabani Taraphder (nee Roy) completed B.Sc. Chemistry (Hons.) from Presidency College, Kolkata and joined the Integrated M.S.-Ph.D. program in Chemistry at Indian Institute of Science, Bangalore. She completed her PhD degree in 1996 in the field of theoretical physical chemistry under the supervision of Prof. Biman Bagchi at the Solid State and Structural Chemistry Unit of IISc Bangalore. Srabani joined as a member of the faculty at the Department of Chemistry, Indian Institute of Technology Kharagpur in 1996. She is currently a Professor at the same department. Her research activity focuses on computer simulation studies of chemical reactions in complex systems. Her academic profile also includes the following.  Visiting Fellow, Harischandra Research Institute, Allahabad.  Visiting fellow, National Institutes of Health, USA.  Visiting faculty and IUSSTF fellow, Henry Eyring Center for Theoretical Chemistry, Department of Chemistry, University of Utah, USA.  Young Associate of the Indian Academy of Sciences, Bangalore.  Regular Associate, International Centre for Theoretical Physics, Trieste, Italy.  Fellowship of the Human Frontier Sciences Program to Instituto de Quimica Fisica Rocasolano, CSIC, Madrid, Spain  INSA Teachers Award (2018) of the Indian National Science Academy, New Delhi.

3rd Charusita Chakravarty Memorial Lecture

Reaction Coordinate, Free Energy and Kinetics in an Enzyme Catalysed Proton Transfer Reaction

Srabani Taraphder*

Department of Chemistry Indian Institute of Technology Kharagpur, India

The molecular mechanism of an enzyme catalysed proton transfer event involves the transfer of excess proton(s) along dynamic pathways comprised of hydrogen bonded networks of amino acid residues and water molecules. The importance of enzyme structure and dynamics on such proton transfer steps is well demonstrated by human carbonic anhydrase II (HCA II), which has long served as a prototype for enzymes containing a rate determining proton transfer step. In this lecture, we shall present a quantitative description of the catalysis by HCA II. For each step in the multi-step catalysis, the reaction coordinate is derived using machine learning methods to reduce the data available from a wide range of relevant structural, mutation, and kinetic experiments supplemented by a large number of theoretical and computer simulation studies. The free energy and rate constants estimated along the reaction coordinates allow us to determine the mechanism that corresponds to the experimentally observed catalytic rate constant of HCA II.

References:

1. Paul, T.K.; Taraphder, S. (submitted, 2020). 2. Paul, S.; Paul, T. K.; Taraphder, S. J. Mol. Graph. Mod. 2019, 90, 18-32. 3. Paul, S.; Paul, T. K.; Taraphder, S. J. Phys. Chem. B 2018, 122, 2851-2866. 4. Paul, T. K.; Taraphder, S. J. Phys. Chem. B 2015, 119, 11403-11415. 5. Roy, A.; Taraphder, S. J. Phys. Chem. B 2009, 113, 12555-12564; ibid 2008, 112, 13597- 13607; ibid 2007, 111, 10563-10576.

26th CRSI National Symposium in Chemistry

Lifetime Achievement Award Lecture

T. Ramasami

Former Secretary to Government of India Ministry of Science and Technology Nayudamma Abdul Wahid Chair Professor Department of Leather Technology, AU CSIR-Central Leather Research Institutte Adayr, Chennai 600 020

Thirumalachari Ramasami is the former Indian Science and Technology Secretary. He assumed charge in May 2006. Prior to this assignment, he served as the Director of the Central Leather Research Institute, Chennai, India. He is a distinguished researcher and leather scientist. He was awarded India's National Civilian Honour the Padma Shri for excellence in Science and Engineering in 2001, and the Padma Bhushan in 2014. He was awarded the Shanti Swarup Bhatnagar Award, the highest award for science in India, for notable and outstanding research in Chemical Sciences in 1993.

Lifetime Achievement Award Lecture

A Story of an evolution of a chemist

T. Ramasami

Knowledge pyramid in science is built on the foundation of curiosity, desire to know, explore un chartered areas and seek truth. Framing the right questions and seeking truthful answers forms the language of science. When such questions and answers deal with real life systems, complexity of questions, answers and systems impacts the professional path of a scientist. Three aspects of scientific research namely discovery, solution and sustainability of solutions become important in different stages of a professional. During discovery phase of research, understanding chemical phenomena becomes a focus of studies. Understanding factors controlling mechanisms of substitution and electron transfer reactions in transition metal complexes and implications of chemistry of chromium in real life systems formed a major thrust during the discovery phase of life. Some key lessons learnt from understanding would be shared. Curiosity and passion for excellence were driving factors in that early career phase of life. At mid-career stage, solution science had become a necessity. Scientific research was then driven by relevance of the solutions for solving real life problems faced by chromium based industries and tanneries. Viable and sustainable scientific solutions to many industrial problems based on the applications of chemistry had to be designed, developed and delivered. ―Do Ecology‖ solutions to environmental problems associated with heavy metal ions and leather processing activity called for deeper understanding of under pinning chemistry. Many were developed and implemented in commercial scale. An industrial catastrophe faced by leather industry in Tamil Nadu was averted through the deployment of viable Do ecology solutions. Saving of jobs and creating employment through technological research were fulfilling. Late career efforts were focused upon service as a chemist. Case studies of some real life solutions to societal problems through applications of broader science would be presented. The talk is planned as a voyage into the ocean of knowledge with chemistry as leading light, service as the purpose of the journey. In short, continuing journey of a chemist is proposed to be shared through his learnings at various stages of professional life in an anecdotal format.

26th CRSI National Symposium in Chemistry

Silver Medal Lectures

Vijayamohanan K Pillai

Indian Institute of Science Education and Research, Tirupati C/o Sree Rama Engineering College (Transit Campus), Rami Reddy Nagar, Karakambadi Road, Mangalam (P.O.) Tirupati -517507, Andhra Pradesh, INDIA Email: [email protected]

Prof. Vijayamohanan K Pillai is a leading Electrochemist from India, who after receiving his Ph.D from the Indian Institute of Science, Bangalore, worked in many areas of electrochemical power sources, electrochemical sensors and bio-electrochemistry for about two decades at the National Chemical Laboratory, Pune. He has authored over 260 publications and 28 patents related to many innovations in both Electrochemistry and Materials Chemistry, while advising about 23 Ph.D. students in Materials Electrochemistry. His group has developed highly sensitive nanostructured platinum electrocatalysts for CO oxidation and Polymer Eelectrolyte Fuel Cells (PEMFC) using Nafion-based composite membranes with functionalized carbon nanotubes and graphenes. His research interests include Materials Electrochemistry, functionalization of carbon nanotubes/graphene nanoribbons and two dimensional quantum dots as electrocatalysts for fuel cells, supercapacitors and rechargeable batteries. He has received many honors and awards like The MRSI Medal, Bangalore in 1996 and CRSI Bronze Medal in 2004. He was a Member of the Editorial Board of Bulletin of Materials Science (2005-2016), Electrocatalysis (2012 onwards) and Scientific Reports (2015 onwards) and is a Fellow of the Indian Academy of Sciences since 2008 and the Indian National Science Academy (2018). He has been an "Erudite visiting professor" at MG University, Kottayam since 2011 and has given ―Professor K.S.G. Doss Memorial Lecture in 2011‖, ―Professor Gurumurthy Mangalam Endowment Lecture, Annamalai University‖ in 2012, ―R.K. Barua Memorial Lecture at the Gauhati University‖ in 2013, ―Prof. Chelikani Chiranjeevi Endowment Lecture Award, Andhra University‖ in 2015, ―IICT-Avon Padmashri Dr. G S Sidhu Chemcon Distinguished Speaker Award-2016‖, ―Prof. B. Thimme Gowda endowment lecture 2015-16‖, Mangalore University, ―National Prize for Research on Energy Materials and Devices‖ by JNCASR, 2016, ―Prof. T. L. Rama Char Memorial Lecture - ECS India‖, 2016, ―MRSI-ICSC Superconductivity and Materials Science Annual Prize‖, 2016, ―Dr. K T Achaya Memorial Award‖ by OTAI, 2017 and ISCB Award for Excellence (Chemical Sciences), 2019. He has also visited many foreign countries like US, Germany, France, Finland, Japan, China, Australia for giving invited lectures on many topics in Materials Electrochemistry and Electrochemical Energy Storage. In addition to being Director of CSIR-CECRI (April 2012 – October 2018), he held the additional charge as Director, CSIR-NCL, Pune from June 2015 to February 2016. He is at present working as the dean (R&D) and chair of Chemistry at IISER-Tirupati and may be contacted at [email protected], or [email protected].

Silver Medal Lectures

Phosphorene Quantum Dots: Electrochemical Preparation, Doping and Possible Applications

Vijayamohanan K Pillai

Indian Institute of Science Education and Research, Tirupati Mangalam (P.O.) Tirupati -517507, Andhra Pradesh, INDIA

Phosphorene quantum dots (PQDs) have emerged as a fascinating class of two-dimensional materials for potential applications in optoelectronics, catalysis, and sensing. In addition to size size- dependant tuning of their electronic properties, the possibility of heteroatom doping at room temperature and surface functionalization to improve poor stability make them especially useful for many optical applications. This lecture addresses various aspects of the structural distortion of black phosphorus (BP) to phosphorene quantum dots during this transformation using results obtained from transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Further,first-principles-based density functional theory, calculations on oxygenated and nonoxygenated PQDs augment the experimental observations that an optimum oxygen content maintains the structural integrity of PQDs, above which the structural robustness of PQDs is drastically diminished. Role of nitrogen doping on their optical and electocatalytic properties is also discussed...

References:

1. A single-step, electrochemical synthesis of nitrogen doped blue luminescence phosphorene quantum dots, Manila et al., Chem. Com.54 (2018)11733 2. Role of Structural Distortion in Stabilizing Electrosynthesized Blue-Emitting Phosphoren Quantum dots, Manila et al J. Phys. Chem. Lett. 10 (2019) 973-980.

Subrata Ghosh

School of Chemical Sciences Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India e-mail: [email protected]

Professor Ghosh obtained Ph. D. in 1978 under the supervision of Late Professor U. R. Ghatak at Indian Association for the Cultivation of Science (IACS), Calcutta. During his Ph. D. he joined the Department of organic Chemistry, IACS as Research Assistant in 1977. He worked as a postdoctoral fellow at Case Western Reserve University with Professor R. G. Salomon as the mentor during 1979- 1981 and 1984-1986 on study leave from IACS. He joined the Department of Organic Chemistry at IACS as Lecturer in1982 and began his independent research career. Subsequently he was promoted to Reader in 1987, Professor in 1994 and Senior Professor in 2005. . He also served IACS as Dean during 2009-2012. He was a visiting scientist at Liecester University for the period October- December, 1997 under INSA-Royal Society Exchange Program. He served as an Editorial Board Member in Journal of Chemical Sciences. He was a member in DST Management Advisory Committee for young Scientists, DST Program Advisory Committee (Organic Chemistry) and in Sectional Committee (Chemical Sciences) of Indian Academy of Sciences, Bangalore. He retired from service in April, 2014. Since then he is continuing his research as a J. C. Bose National Fellow. Research interest includes total synthesis of natural products, development of new synthetic methodologies, cycloaddition reactions, olefin metathesis, Chiron approach to asymmetric synthesis etc.

Silver Medal Lectures

Natural Products Synthesis – Some Fascinating Aspects

Subrata Ghosh

School of Chemical Sciences Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India

Natural products have long been recognized as an invaluable source for the discovery of numerous therapeutic agents. The structural diversity and complexity coupled with therapeutic potential, natural products have stimulated great deal of interest for development of synthetic routes. Bridged- and fused polycyclic systems with highly complex molecular structures are frequently encountered in a variety of natural products. Some of the compounds of contemporary interest include shinortriterpenoids such as schintrilactones 1, diterpene ingenol 2, artemisinin 3 and gracilioether F 4. These compounds are associated with a multitude of bio-activities beneficial to mankind. For example, schintrilactones exhibit anti-HIV activity while few derivatives of ingenol show anti-cancer activity. Compound 3 is an anti-malarial while 4 possesses antifungal properties. Synthesis of these complex molecular structures is a formidable task. Some fascinating aspects observed during our efforts1-5 towards the synthesis of these and related compounds will be presented.

References:

1. Malik, C. K.; Ghosh S. Org. Lett. 2007, 9, 2537-2540. 2. Malik, C. K.; Yadav, R. N.; Drew, M. G. B.; Ghosh, S. J. Org. Chem. 2009, 74, 1957-1963. 3. Maity, S.; Matcha, K.; Ghosh, S. J. Org. Chem. 2010, 75, 4192-4200. 4. Mondol, S.; Yadav, R. N.; Ghosh, S. Org. Lett. 2011, 13, 6078-6081. 5. Datta, R.; Ghosh, S. J. Org. Chem. 2017, 82, 7675-7682.

26th CRSI National Symposium in Chemistry

Bronze Medal Lectures

Ranjani Viswanatha

International Centre for Materials Science Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore 560064 Email: [email protected]

Ranjani Viswanatha is currently working as an associate professor at Jawaharlal Nehru Centre for Advanced Scientific Research. She did her Ph. D. at the Indian Institute of Science under the guidance of Prof. D. D. Sarma on the growth in solution and electronic structure of nanocrystals. Subsequent to her Ph.D. work, she has been worked as a postdoctoral fellow at Prof. Xiagong Peng‘s laboratory at the University of Arkansas and at the Los Alamos National Lab in Prof. Victor Klimov's group before joining JNCASR. Her work revolves around some interesting behavior of transition metal dopants in nanocrystals qualitatively different from the bulk. Her work has been published in leading journals and she has been awarded several national awards like Karnataka State C V Raman award, MRSI medal, DST Young Nanoscientist award, Sheikh Saqr Fellowship, founding member of Indian National Young Academy of Science, the INSA young scientist medal and chosen as a young associate of Indian Academy of Science, founder member of Indian National Young Academy of Science among many others. She is also a reviewer in many of the leading journals and has given several talks in leading conferences.

Bronze Medal Lectures

Mn emission: Energy transfer or Charge transfer

Ranjani Viswanatha

International Centre for Materials Science Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064

Quantum dots, wherein size-dependent properties are often observed, are of great scientific interest as they effectively act as a bridge between the bulk properties and the atomic or molecular properties. Doping transition metal ions in quantum dots provide great flexibility in controlling electronic and magnetic interactions via growth-controlled ―engineering‖ of wave functions giving rise to interesting properties, including lasing, giant magneto-optical properties. Manganese is one of the most extensively studied dopants in this category. This interest is primarily piqued by the interesting orange emission arising from the Mn d-d transition. While the practical observation and manifestations of this emission has led to several applications like photo-magnetism, the physics of its origin has continued to intrigue many researchers with its spin forbidden nature. Two main concepts that have been used to understand this emission is the energy transfer and charge transfer. Most of the literature in this field now believe it to be an energy transfer process. In this talk, I am going to discuss the typical signatures of energy and charge transfer and various recent experimental observations that cannot be explained using energy transfer.1,2 I also present some theoretical results demonstrating the viability of charge transfer.3

References:

1. R. Viswanatha; J. M. Pietryga; V. I. Klimov; S. A. Crooker, Phys. Rev. Lett. 2011, 107, 067402. 2. K. R. Pradeep; D. Acharya; P. Jain; K. Gahlot; A. Yadav; A. Cammelini; M. Zavelani-Rossi; G. Cerullo; C. Narayana; S. Narasimhan; R. Viswanatha; ACS Ene. Lett. (In Press). 3. K. Gahlot; K. R. Pradeep; A. Cammelini; G.Sirugu; G. Cerullo; M. Zavelani-Rossi; A. Singh; U.V. Waghmare; R. Viswanatha, ACS Ene. Lett. 2019, 4, 729-735.

Manmohan Kapur

Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, INDIA. E-mail: [email protected]

Personel webpage: https://sites.google.com/a/iiserb.ac.in/mk-group-iiserb/

Bronze Medal Lectures

Transition-metal-catalyzed Distal and Remote Functionalizations

Manmohan Kapur

Department of Chemistry, Indian Institute of Science Education and Research Bhopal Bhopal Bypass Road, Bhauri, Bhopal 462066, INDIA.

The site-selective functionalization of distal or remote positions with respect to a reactive functional group in an organic framework, has always been a synthetic challenge for chemists.1 Achieving this by the rational design of the substrate to be functionalized, comes with positional-selectivity challenges of its own. The C-H functionalization of organic molecules is now a quite well-developed field. The transition-metal mediated C-H functionalization of bonds in the immediate vicinity of Lewis- basic directing groups is one approach that has been widely-utilized for proximal bond functionalization. This directing-group approach has also been utilized for C-H functionalization of distal bonds using extended tethers. In another approach, using an extended -system conjugated to a heteroatom, distal C-H functionalizations can be achieved, often by Pd-catalysis. The remote functionalization of -conjugated systems via low-valent transition-metal catalysis has its own challenges, in terms of selectivity of the sp2 bond being functionalized. This talk shall focus on these aspects, Pd-catalyzed distal and remote functionalization of extended sp2-systems and our recent contributions to these areas. 2-3

References:

1. Vasseur, A.; Bruffaerts, J.; Marek, I. Nature Chemistry, 2016, 8, 209–219. 2. (a) Pawar, G. G.; Singh, G.; Tiwari, V. K.; Kapur, M. Adv. Synth. Catal. 2013, 355, 2185-2190; (b) Tiwari, V. K.; Pawar, G. G.; Das, R.; Adhikary, A.; Kapur, M. Org. Lett. 2013, 15, 3310- 3313. (c) Tiwari, V. K.; Pawar, G. G.; Jena, H. K.; Kapur, M. Chem. Commun. 2014, 50, 7322- 7325. (d) Tiwari, V. K.; Kamal, N.; Kapur, M. Org. Lett. 2017, 19, 262-265. (e) Kumar, P.; Kapur, M. Org. Lett. 2019, 21, 2134-2138. (f) Das, R.#; Khot, N. K.#; Deshpande, A. S.; Kapur, M. Chem. -Eur. J. 2019, 25, 0000 (doi.org/10.1002/chem.201904512) (#equal contribution). 3. Saini, G.; Mondal, A.; Kapur, M. Org. Lett. 2019, 21, 9071-9075.

Rajakumar Balla

Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India

Rajakumar Balla Born in a very remote village of the Srikakulam District of Andhra Pradesh to Sri Suryanarayana and Smt. Jayalakshmi in 1971. Obtained B. Sc from Sri Durgaprasad Sharaf college of arts and applied sciences, Sriram Nagar, Garividi of Vizianagaram District of Andhra Pradesh. Studied M. Sc in Chemistry in the School of Chemistry, Andhra University Visakhapatnam. Introduced to the field of gas phase physical chemistry by Prof. E. Arunan at the Department of Inorganic and Physical Chemistry of the Indian Institute of Science Bangalore and obtained Ph. D in 2002 under his supervision. Further, pursued research in the area of the atmospheric chemistry and physics as a post doctoral researcher under the leadership of the famous scientist Prof. Dr. A. R. Ravishankara at the National Oceanic and Atmospheric Administration (NOAA), Boulder, Colorado, U. S. A. Returned to India in 2006 and joined the Department of Chemistry at the Indian Institute of Technology Madras as an Assistant Professor and currently working as a Professor.

Bronze Medal Lectures

Measurement of absorption cross-sections and kinetics of radicals relevant to the Earth’s atmosphere using Cavity Ring Down Spectroscopy

B. Rajakumar

Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036

When a compound is released into the Earth‘s atmosphere, on one hand it undergoes photo dissociation when exposed to the light and on the other hand it reacts with very important oxidizing agents. Therefore, the loss of a compound depends on both photo-physical as well as photo-chemical processes, in the Earth‘s atmosphere. Photo induced radical chemistry plays a very important and vital role in the Earth‘s atmosphere in terms of Global Warming, Ozone loss and Climate change. As aliphatic as well as aromatic hydrocarbons takes the major stack in the chemical composition of the Earth‘s atmosphere, it is essential to understand the chemistry initiated by them in the presence of light. On these grounds, measurement of absorption cross-sections of important radicals such as propionyl and phenyl radicals were undertaken as a first step in the process of understanding their photo-chemical properties as well as kinetics with important molecules. Cavity Ring Down Spectroscopy (CRDS), which is essentially a supersensitive optical spectroscopic tool works on the principle of Fabry-Perrot cavity is used to measure the absorption cross-sections and kinetics with important molecules. The CRD spectrometer was built in our research lab at IIT Madras. The propionyl radical, CH3CH2CO, which is of importance in both atmospheric and combustion chemistry rapidly converted to propionyl peroxy radical via its reaction with O2 which, in turn leads to the 4 formation of peroxypropionylnitrate (PPN, CH3CH2C(O)O2NO2). PPN is an atmospheric reservoir for

NOX (NO+NO2). PPN concentrations of up to 4 ppb have been measured and reported in urban 5 areas . The visible absorption spectrum of the propionyl radical, CH3CH2CO was measured between 555 and 595 nm at 298 K using cross photolysis cavity ring-down spectroscopy. In addition to this, absorption cross-sections of yet another important radical, Phenyl radical was measured and they were used to measure the kinetics with methanol. The details of the experimentation and results will be discussed in the conference.

Reference:

1. Koushik Mondal, Revathy Kaipara and B. Rajakumar. J. Phys. Chem. A 2019, 123, 9682- 9692

Seergazhi Gopalan Srivatsan

Indian Institute of Science Education and Research (IISER), Pune, India 411008 Email: [email protected]

S. G. Srivatsan received his master‘s degree in Chemistry from Indian Institute of Technology, Madras in 1995 and Ph. D. in Bioorganic Chemistry from Indian Institute of Technology, Kanpur in 2003 under the supervision of Prof. Sandeep Verma. He was an Alexander von Humboldt postdoctoral fellow with Prof. Michael Famulok at University of Bonn, Germany, where he developed catalytic RNAs and pharmacophores that target protein-RNA complexes and their enzyme activity. Subsequently, he joined Prof. Yitzhak Tor group as a postdoctoral fellow in University of California, San Diego. He joined Indian Institute of Science Education and Research (IISER), Pune in November 2008. He is currently a Professor and Wellcome Trust-DBT India Alliance Senior Fellow. He recently received the CDRI AWARDS–2019 for Excellence in Drug Research and serves as an Editorial Advisory Board member of ACS Bioconjugate Chemistry. He is also nominated to receive the Chemical Research Society of India Bronze medal for 2020. His research interests lie in the area of nucleic acid chemistry and biophysics, particularly in the development of nucleoside probes for studying nucleic acid structure and function, functionalized nucleoside-based self-assemblies, and nucleic acid labeling and imaging tools. Webpage: http://www.iiserpune.ac.in/~srivatsan

Bronze Medal Lectures

Probing Mood (Structure) Swings of Non-Canonical Nucleic Acid Motifs

Seergazhi Gopalan Srivatsan

Indian Institute of Science Education and Research (IISER), Pune, India 411008

Numerous biophysical tools have provided efficient systems to study nucleic acids. However, our current understanding on how nucleic acid structure complements its function, particularly in cellular environment, is limited. This general limitation is largely due to the lack of probes that can be used in both cell-free and cellular assays, and in more than one biophysical technique. Hence, correlating the information obtained under equilibrium conditions, in solid state and in cells becomes very difficult using uniquely-labeled oligonucleotide sequences. In this context, moving away from the tradition approach of ―one label one technique‖ we adopted an innovative approach to investigate the nucleic acid structure and function in cell-free and cellular environments by using conformation-sensitive multifunctional nucleoside analog probes. Based on this strategy, we have developed nucleoside analogs equipped with two or more labels (eg., fluorophore, NMR isotope label and X-ray crystallography phasing atom), which serve as common probes for analyzing nucleic acid motifs simultaneously by using a combination of fluorescence, NMR and X-ray crystallography techniques.1-4 In this presentation, design and synthesis of multifunctional nucleoside probes, and their utility in investigating the structure and ligand binding properties of a therapeutically important non-canonical nucleic acid motif (G-quadruplex) in real time, in 3-dimension and in native cellular environment will be discussed.

References:

1. Nuthanakanti, I. Ahmed, S. Y. Khatik, K. Saikrishnan, S. G. Srivatsan, Nucleic Acids Res., 47, 6059 (2019). 2. S. Manna, D. Sarkar, S. G. Srivatsan, J. Am. Chem. Soc., 140, 12622 (2018). 3. A. Nuthanakanti, M. A. Boerneke, T. Hermann, S. G. Srivatsan, Angew. Chem. Int. Ed., 56, 2640 (2017). 4. A. A. Tanpure, S. G Srivatsan, Nucleic Acids Res., 43, e149 (2015).

Mahesh Hariharan

School of Chemistry, IISER-TVM E-mail: [email protected]

Dr. Mahesh Hariharan has completed his Ph.D from National Institute for Interdisciplinary Science and Technology, Trivandrum, Kerala under the supervision of Prof. Danaboyina Ramaiah in the year 2006. He did his postdoctoral research from Northwestern University, Illinois, USA under Prof. Frederick D. Lewis in the year 2007-2009. He has joined in IISER-TVM as an assistant professor in the year of 2009. He has been promoted to Associate professor in the year of 2014. He is also a visiting professor in University of Wuerzburg, Germany and Montana State University, Montana, USA. He is associated with Royal Society of Chemistry; American Chemical Society; Asian and Oceanian Photochemistry Association; Inter-American Photochemical Society; European Photochemistry Association; International Association of Advanced Materials; Chemical Society of Japan, Japanese Photochemistry Association, Chemical Research Society of India; Materials Research Society of India; Indian Society for Radiation and Photochemical Sciences, Photosciences Research Society of India; Kerala Academy of Sciences, India. He has published 57 publications in reputed international journals. He has completed two research grants from DST and DBT. Currently, he has two ongoing projects.

Bronze Medal Lectures

Ultrafast Excited State Dynamics of Twisted Aromatics

Mahesh Hariharan

School of Chemistry, IISER-TVM

Self-assembling of organic chromophoric systems into elegant supramolecular architectures with emergent properties has received prodigious attention in recent years.1 The notion of ‗emergence upon assembly‘ is evidenced in the unusual photoexcited state dynamics exhibited by chromophoric assemblies. In the first example, a naphthalene-naphthalimide donor-acceptor (D-A) dyad assembled into segregated D-A stacks in the crystalline state. The photo-induced charge separated state in the aggregate state lasts 10,000 times longer than the monomeric dyad. The femtosecond transient absorption spectra depicted the spectroscopic signature for naphthalene dimer radical cation indicating the migration of charges through the stacks.2 In the second example, we report the crystalline evidence for Greek cross‐dipole (α=90°) stacking of 1,7‐dibromoperylene‐3,4,9,10‐ tetracarboxylic tetrabutylester (PTE‐Br2) displaying null excitonic coupling and thereby monomeric optical behavior. Additionally, the semi‐classical Marcus theory of charge‐transfer rates predicted a 3 selective hole transport phenomenon in the orthogonally stacked PTE‐Br2. In the third example, we showcase a radial assembly of 1,8-dibromonaphthalene(2,6-diisopropylphenyl)imide (NIBr2) in 4 5 crystalline phase driven by hexabromine synthon. NIBr2 exhibits ultrafast intersystem crossing and solid-state room temperature phosphorescence. We believe the fundamental understanding of noncovalent interactions dictating the unorthodox assembly of chromophores6-7 and probing of emergent properties are paramount for the rational design and construction of robust functional materials.

Figure. Representative strategies adopted in our group to spatially organize organic chromophores for emergent properties.

References:

1. Cheriya, R. T.; Mallia, A. R.; Hariharan, M. Energy Environ. Sci. 2014, 7, 1661. 2. Mallia, A. R.; Salini, P. S.; Hariharan, M. J. Am. Chem. Soc. 2015, 137, 50, 15604. 3. Sebastian, E.; Philip, A. M.; Benny, A.; Hariharan, M. Angew. Chem., Int. Ed. 2018, 57, 15696. 4. Niyas, M. A.; Ramakrishnan, R.; Vijay, V.; Sebastian, E.; Hariharan, M. J. Am. Chem. Soc. 2019, 141, 4536. 5. Nagarajan, K.; Mallia, A. R.; Muraleedharan, K.; Hariharan, M. Chem. Sci. 2017, 8, 1776. 6. Ramakrishnan, R.; Niyas, M. A.; Lijina, M. P.; Hariharan, M. Acc. Chem. Res. 2019, 52, 3075-3086 7. Mohan, A; Sasikumar, D.; Bhat, V.; Hariharan, M. Angew. Chem., Int. Ed. 2020, 59, 2-9.

Ashwani K. Tiwari

Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246 Email: [email protected]

Ashwani K. Tiwari is a Professor of Theoretical Chemistry at the Indian Institute of Science Education and Research (IISER) Kolkata. His research interests involve the quantum dynamics of laser– molecule and molecule–metal surface interactions. He received his Ph.D. in theoretical chemistry working under the supervision of Prof. N. Sathyamurthy at the Indian Institute of Technology, Kanpur, in 2007. During the period May 2007–April 2008, he was a postdoctoral fellow with Prof. Niels E. Henriksen at the Technical University of Denmark. From May 2008 to April 2010, he was a postdoctoral fellow with Prof. Bret Jackson at the University of Massachusetts, Amherst. He joined IISER Kolkata as an Assistant Professor in the year 2010, became Associate Professor in 2015 and full Professor in 2019.

Bronze Medal Lectures

Effects of Mode-Mode Coupling on the Dissociation Dynamics of H2O and CH4 on Metal Surfaces

Ashwani K. Tiwari*

Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246 *

Dissociation of H2O on metal surfaces is rate-limiting step in many industrially important reactions. In a few recent experiments, it has been observed that dissociations of H2O on metal surfaces is mode- selective. In other words, this reaction is not statistical in nature and therefore, one cannot use transition state based theory to get insights of this reaction. Our quantum dynamical calculations show that mode-mode coupling along reaction path is the key factor in deciding the quantum of mode- selectivity in this reaction.

Fig1. Dissociation sticking probabilities as a function of incident energies for the vibrational ground state and several initial vibrationally excited states of H2O on Ni(111) surfaces at 300K.

References:

1. A. Mondal, H. Seenivasan, and A. K. Tiwari, J. Chem. Phys. 137, 094708 (2012) 2. P.M. Hundt, B. Jiang, M.E. van Reijzen, H. Guo, and R.D. Beck, Science 344, 504 (2014). 3. H. Seenivasan, B. Jackson and A. K. Tiwari J. Chem. Phys, 146, 074705 (2017). 4. D. Ray, S. Ghosh and A. K. Tiwari J. Phys. Chem. A, 122, 5698-5709 (2018) 5. S. Gosh, D. Ray, and A.K. Tiwari, J. Chem. Phys150, 114702 (2019). 6. D. Migliorini, F. Nattino, A. K. Tiwari and G-Jan. Kroes J. Chem. Phys., 149, 244706 (2018)

Ekambaram Balaraman

Department of Chemistry Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati-517507, India E-mail: [email protected]; [email protected]

Personel webpage: https://sites.google.com/view/balaramansresearchgroup/home

Bronze Medal Lectures

Non-noble metal catalysis: Applications in dehydrogenation and related reactions

Ekambaram Balaraman*

Department of Chemistry Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati – 517507, India.

Catalytic dehydrogenation is one of the most fundamental processes in synthetic chemistry and chemical biology. Recently, acceptorless dehydrogenative coupling (ADC) and hydrogen-atom (HA) transfer reactions of renewable chemical feedstocks with the liberation of molecular hydrogen/water open a new avenue in contemporary organic synthesis and have manifold practical applications in sustainable energy.[1] Despite significant advances achieved in noble-metal catalysis, the limited terrestrial abundance, and the high cost and high-degree price fluctuation of precious-metal catalysts and the supporting ligands have prompted chemists and chemical industrialists to search for new sustainable catalysts to facilitate practical applications. Thus, the replacement of noble metals with base metals for similar or better reactivity is one of the promising approaches in homogeneous catalysis. However, the search for an efficient catalytic system based on base-metal catalysts for sustainable chemical transformations is extremely rare.[2] We have successfully designed and prepared a new cheap-metal based catalysts (Mn, Fe, Co, Ni) and applied in various synthetic transformations.[3] Herein, some of our recent progress on acceptorless dehydrogenation and related reactions using cobalt, and nickel complexes will be discussed.

References:

1. (a) A. Nandakumar, S. P. Midya, V. G. Landge, E. Balaraman, Angew. Chem. Intl. Ed., 2015, 54, 11022 (Minireview). (b) E. Balaraman, A. Nandakumar, G. Jaiswal, M. K. Sahoo, Catal. Sci. Technol., 2017, 7, 3177. 2. (a) G. Jaiswal, V. G. Landge, D. Jegadeesan, E. Balaraman, Nature Commun., 2017, 8, 2147. (b) S. P. Midya, V. G. Landge, M. K. Sahoo, J. Rana, E. Balaraman, Chem Commun., 2018, 54, 90. (c) V. G. Landge, A. Mondal, V. Kumar, A. Nandakumar, E. Balaraman. Org. Biomol. Chem., 2018, 16, 8175. (d) A. Mondal, M. Subaramanian, A. Nandakumar, E. Balaraman. Org. Lett., 2018, 20, 3381. (e) J. Rana, R. Babu, M. Subaramanian and E. Balaraman. Org. Chem. Front., 2018, 5, 3250. (f) V. G. Landge, V. Yadav, M. Subaramanian, P. Dangarh, E. Balaraman. Chem. Commun., 2019, 55, 6130.

Gouriprasanna Roy

Department of Chemistry Indian Institute of Technology Tirupati (IIT Tirupati), Tirupati, AP – 517 506 E-mail: [email protected]

Education PhD, 2007 - Department of Inorganic and Physical Chemistry (IPC), Indian Institute of Science (IISc), Bangalore, India. Advisor: Prof. G. Mugesh MSc, 2002 - Chemistry, University of Calcutta, Kolkata, India. Professional Experience Jan 2020 – Associate Professor, Department of Chemistry, Indian Institute of Present Technology Tirupati (IIT-Tirupati), Tirupati, A.P – 517 506. July 2018 – Associate Professor, Department of Chemistry, Shiv Nadar University Jan2020 (SNU), Greater Noida, Gautam Budh Nagar, UP-201 314. November 2012 -JuneAssistant Professor, Department of Chemistry, SNU, Greater Noida, UP- 2018 201 314. November 2011 Research Associate, Department of Chemistry, The Scripps Research – Institute, San Diego, USA. September 2012 January 2008 – Post-doctoral Fellow in Chemical Biology program, Department of November 2011 Physiology and Pharmacology, Oregon Health and Science University June 2007 – (OHSU). Oregon, USA. December 2007 Research Associate, Department of Inorganic and Physical Chemistry, Indian Institute of Science (IISc), Bangalore, India.

Bronze Medal Lectures

Biomimetic Studies to understand the mechanism of Hg−C bond protonolysis by mercury-resistant Organomercurial Lyase MerB

Gouriprasanna Roy Department of Chemistry Indian Institute of Technology Tirupati (IIT Tirupati), Tirupati, AP – 517 506

+ Methyl mercury (MeHg ) is a ubiquitous environmental pollutant and a potent neurotoxin. It accumulates at high levels in food chains, mainly in fish and seafood, and therefore, consumption of these contaminated foods 1 + poses a significant risk to human health. On the other hand, exposure to ethyl mercury (EtHg ) is an another + serious concern in developing countries where EtHg -containing antimicrobial agent ―Thimerosal‖ is commonly 2 used as a preservative in multiuse vials of vaccines and in other medicines. In nature, however, several + microorganisms have been reported to detoxify organomercurials including MeHg by converting them to less toxic biologically inert species. For instance, bacterial organomercurial lyase (MerB) catalyzes the + protolytic cleavage of the otherwise inert Hg C bond of MeHg and produces methane (CH4) gas and ionic 2+ 2+ 0 mercury Hg , while a second enzyme mercuric ion reductase (MerA) reduces the product Hg to volatile Hg . + On the other hand, several sulfate reducing bacteria (SRB) convert highly toxic MeHg to less toxic 3 insoluble HgS(s) (metacinnabar) by producing H2S during metabolism. In fact, insoluble mercury selenide (HgSe) have been detected in various tissues of marine mammals and also detected in different organs + (kidney, liver, muscle, and brain) of humans exposed to MeHg . Inorganic HgSe is considered to be much less + toxic than the mobile, water-soluble MeHg species including MeHgCys and MeHgSG. In this talk, I will mainly focus on how small synthetic molecules can be used intelligently to detoxify toxic organomercurials in 4,5 various pathways, similar to those observed in nature.

References: 1. Clarkson, T. W.; L Magos Crit. Rev. Toxicol. 2006,36, 609–662. 2. Geier, D. A.; King, P. G.; Hooker, B. S.; Dórea, J. G.; Kern, J. K.; Sykes, L. K.; Geier, M. R. Chimica Acta 2015, 444, 212–220. 3. Omichinski, J. G. et al. J. Biol. Chem. 2009, 284, 938–944. 4. (a) Roy, G. et al. Angew. Chem., 2015, 127, 9455–9459; Angew. Chem. Int. Ed., 2015, 54, 9323– 9327; (b) Roy, G. et al. Chem. Eur. J, 2017, 23, 5696–5707; (c) Roy, G. et al. Inorg. Chem. 2017, 56, 12739–12750. (d) Roy, G. et al. Inorg. Chem. 2017, 56, 12102–12115. (e) International Patent filed (PCT): WO2017168451. 5. Roy, G. et al. Chem. Comm. 2020, xx, xxxx.

Santanu Kumar Pal

Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector-81, Sahibzada Ajit Singh Nagar, Knowledge City, Manauli 140306, India E-mail: [email protected]

Santanu Obtained his B. Sc. from Ramakrishna Mission Vidyamandira, Belur (2001) and M.Sc. from University of Calcutta (2003). After completing his doctoral studies in 2008 at Raman Research Institute, Bangalore, he worked as a postdoctoral fellow at University of Wisconsin-Madison, USA (2008-2010). In 2010, he returned to India to join Indian Institute of Science Education and Research, Mohali as an Assistant Professor and was promoted to Associate Professor in 2016. His research interest‘s primary revolve around Supramolecular Chemistry in particular, discotic liquid crystals in Organic electronic devices and Biological Sensing using soft and Active matters. He has published more than 100 publications in reputed peer reviewed international journals. Santanu is a recipient of the Indian National Science Academy (INSA) Medal for Young Scientists (2015), the National Academy of Sciences, India (NASI)-Young Scientist Platinum Jubilee Award (2015), DST-Young Scientist Award (2012) and DAE Young Achiever Award (2014) from BOARD OF RESEARCH IN NUCLEAR SCIENCES (BRNS), INDIA. He has been chosen to receive The CRSI Bronze Medal (2020) in recognition of his contributions to research in Chemistry from Chemical Research Society of India.

Bronze Medal Lectures

Highly Efficient Ambipolar Charge Transport in Semiconducting Discotic Liquid Crystals

Santanu Kumar Pal*

Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector-81, Sahibzada Ajit Singh Nagar, Knowledge City, Manauli 140306, India

The hunt for condign ambipolar charge transport materials remains a significant challenge over the past few years. To achieve such demand, intensive efforts are being made using organic semiconductors that carries high electrical performance as well as can be easily processed using different solution processing techniques. However, the crucial challenge is to find a subtle balance between the mobility and processability of these materials. For example, single crystals, known for high mobilities, suffer from inherent fragility and flexibility, which limit their usability in devices. Similarly, in polymeric systems, inadequate solubility, low purity, and structural and energetic disorder have curbed their charge transport properties. To overcome these challenges, recent research has focused on organic small molecules, which offer solution-processed, defect-free films along with high chemical purity. In this context, discotic liquid crystals (DLCs) comprising a central rigid aromatic core substituted with a mantle offer flexible alkyl chains, are currently in the spotlight of material scientists. This talk will unmask a unique ability of Heterocoronene1 based DLCs and others2 to serve as highly efficient ambipolar charge carrier transporting organic semiconductor when used in Space Charge Limited Current (SCLC) devices. These bipolar transport materials would be highly cost-effective due to incorporation of a single layer of organic materials in device architecture. Our results are comparable with the best amorphous as well as polycrystalline organic semiconductors reported till date.

References:

1. De, J.; Bala, I.; Gupta, S. P.; Pandey, U. K. Pal, S. K.* J. Am. Chem. Soc. 2019, 141, 18799- 18805. 2. Bala, I.; Yang, W. Y.; Gupta, S. P.; De, J.; Yadav, R. A. K.; Singh, D. P.; Dubey, D. K.; Jou, J. H.; Douali, R.; Pal, S. K.* J. Mater. Chem. C. 2019, 7, 5724-5738.

26th CRSI National Symposium in Chemistry

Invited Lectures

R. Vijayaraghavan

Professor Department of Chemistry, School of Advanced Science, VIT, Vellore, 632 014 Email: [email protected]

Rajagopalan Vijayaraghavan studied his Undergraduate and Master’s at University of Madras, Chennai and Doctor of Philosophy at Indian Institute of Science, Bangalore . He then pursued his post doctoral research at ISMRA- CRISMAT, Caen, France, ICMAB- Barcelona Spain, IIT Madras for about 7 years. He joined with VIT in 2002 and continued his area of research on Inorganic Solid State Materials related to Energy and Environment as well biomedical. He has been a visiting Scientist at Nagoya University Japan, Inorganic Chemistry Laboratory, Oxford University (Commonwealth fellow), UK and RMIT & University of Melbourne, Australia, JNCASR Bangalore. During his stay in UK as a Commonwealth Fellow, he was selected as a distinguished foreign fellow He has been awarded with Materials Research Society of India (MRSI) medal and Solid State chemistry medal. He is passionate about what he is doing. His hobbies are chess, music and tennis.

Invited Lectures

Development of Sensors & Prototype Set up for Fruit Ripening Applications

R. Vijayaraghavan

Department of Chemistry, School of Advanced Science, VIT, Vellore, 632 014

Fruits while ripening release ethylene, in general, through bio synthesis in ppm level. The amount of ethylene released is an indicator on the state of fruit ripening and hence the measurement of ethylene is of importance during the post-harvest of the fruits and also during transportation of the fruits, in order to avoid over ripenin. However, a concentration as low as 1 ppm of ethylene exposed in the fruit ripening environment is sufficient to promote the fruit ripening process. Artificial ripening agents (calcium carbide) trigger ripening process in apple, avocado, banana, mango, papaya, pineapple and guava. Therefore, the fruits can be sold before the predicted natural ripening time for making more profit. Artificially ripened fruits cause health hazards to consumers .There is a need to differentiate natural and artificial fruit ripening effectively on site for societal benefit in order to suppress the latter, Towards this objective, we have developed MWCNT based chemical sensor and IR absorption based physical sensor & Lab based proto types to detect and estimate ethylene. It is interesting to note that the rate of release of ethylene during artificial ripening is much faster& higher than the natural one. Our methods have better performance in terms of sensitivity. novelty of the sensor element and could differentiate the process effectively.

Ethylene release in natural and artificial fruit ripening by our MWCNT sensor

References:

1. J. Kathirvelan, R. Vijayaraghavan, J. Sensors, 2014, 39505-09, 2. J. Kathirvelan, R. Vijayaraghavan, Infrared. Phy. Tech., 2017, 85, 403-409. 3. J. Kathirvelan R. Vijayaraghavan Review Article, Sens. Rev. 2020 ( accepted).

Hongdoo Kim

Professor Department of Advanced Materials Engineering for Information & Electronics, Kyung Hee University, Yongin, Gyeonggido 17104, Korea Email: [email protected]

Hongdoo Kim was awarded his Ph.D degree in Physical Chemistry from Univ. of Wisconsin-Madison, Wisconsin, U.S.A in the year 1987. He did his post doc from the University Wisconsin-Madison and NIST, Gaithersberg, MD. Currently he is working as full Professor in Kyung Hee University. He has published 61 publications, 12 Korean Patents, 3 US Patents. Currently he is having 3 ongoing National Projects.

Invited Lectures

HYBRID PIEZOCAPACITIVE/PIEZOELECTRIC SENSOR BASED ON ELECTROSPUN NANOFIBER WEBS

Mohammad Shamim Reza1, Arun Anand Prabu2, Hongdoo Kim*1,2

1 Department of Advanced Materials Engineering for Information & Electronics, Kyung Hee University, Yongin, Gyeonggido 17104, Korea 2 Department of Chemistry, School of Advanced Science, VIT, Vellore 632014, Tamil Nadu, India

Recently, polymer-based flexible tactile/pressure sensors have attracted widespread interest among researchers and technologists working in soft robotics, wearable and/or health monitoring devices, etc. In our previous study, a piezo-capacitive sensor based on electrospun polyurethane (PU) nanofiber having very high amount of nano-sized open cells was used for monitoring both static and dynamic pressures [1]. In another study, electrospun polylactic acid (PLA) exhibited high shear- piezoelectricity due to its inherent helix orientation and preferential aligning of C=O functional groups under applied DC voltage [2]. In this study, we attempted coaxial electrospinning of PU-PLA under controlled conditions to obtain core-shell (PLA-PU) structured nanofiber web, and electrospinning of PU-PVDF blend solution to investigate their physico-mechanical and piezo-responsive behaviors. The piezocapacitive/piezoelectric hybrid sensors are capable of simultaneously measuring piezocapacitance as well as piezoelectricity by applying pressure using LCR meter, Dynamic tester and Piezo Film Amplifier. The piezoelectric signals are strongly dependent on the ratio of piezoelectric part and piezocapacive part under external pressure, whereas piezo capacitance under applied pressure linearly increases with decreasing thickness of the nanoweb due to the rubbery PU shell part [3,4]. Moreover, PU-PLA nanoweb based on stacking hybrid was also fabricated and investigated for their piezo-responsive characteristics.

Figure. Time vs voltage signal curves for (a) neat PLA and (b) PU-PLA (shell/core, 55/45 (w/w)). Single cycle load vs capacitance hysteresis curves for (c) neat PU, (d) neat PLA and (e) PU-PLA (shell/core, 55/45 (w/w)) nanoweb-based sensors under external pressure. References

1. M.S. Reza, K.R. Ayag, M.K. Yoo, K.J. Kim, H. Kim, Fiber. Polym., 20(2), 337-347 (2019). 2. S. J. Lee, A. A. Prabu, K. J. Kim, Mater. Lett., 148, 58-62 (2015). 3. R.T. Selvan, Y. J. Ahn, K. J. Kim, H. Kim, Fiber. Polym., 18, 1898-1905 (2017). 4. E. S. Guerra and E.V. Lima, Handbook of Polymer Synthesis, Characterization, and Processing, 53 (2013).

Annamalai Senthil Kumar

Nano and Bio-electrochemistry Research Laboratory, Department of Chemistry, School of Advanced Sciences and CO2 Research and Green Technology Centre, Vellore Institute of Technology University, Vellore-632 014, India

A. Senthil Kumar is a Senior Professor in Carbon dioxide Research and Green Technology Centre of Vellore Institute of Technology University, India. He obtained his Ph.D degree in department of Physical chemistry, University of Madras, India in 2000. He was a postdoctoral fellow in Prof. J.-M. Zen‘s laboratory, National Chung Hsing University, Taiwan for about 7 years (1998-2005) and as a Japan Society for the Promotion of Science (JSPS) fellow with Prof. Tanase, Nara Women‘s University, Japan for 2 years (2005-2007). He has published over 151 international peer-reviewed journals (on 29th Nov 17) and having the Scopus h-index value 29 (on 29th July' 17). His research interest includes interdisciplinary areas of material science, physical & analytical chemistry in particular of designing and application of nanostructured chemically modified electrodes, encapsulation of organic and pharmaceutical molecules within carbon nanotubes, electrocatalysis, nanoparticles and chemical & biosensors.

Invited Lectures Redox Active Organic Molecule Functionalized Carbon Nanomaterials for Elegant Electrochemical Immuno-sensing of Shrimp-Virus

Annamalai Senthil Kumar Nano and Bio-electrochemistry Research Laboratory, Department of Chemistry School of Advanced Sciences and CO2 Research and Green Technology Centre, Vellore Institute of Technology University, Vellore-632 014, India

White spot syndrome virus (WSSV), a new family of viruses named Nimaviridae, genus Whispovirus, is a highly lethal, contagious and the most serious viral pathogen to penaeid shrimp. It causes 100% mortality within 3–7 days of attack. Since the first outbreak in Taiwan in 19923, WSSV has been spreading worldwide and resulting in huge economic loss in the shrimp aquaculture industries. In India, the gross economic loss due the WSSV attack was estimated as 48717 metric-ton of shrimp, which is equivalent to USD 150 million and employment of 2.15 million man days. WSSV disseminates quickly under normal environmental condition and infects a wide host range of host which includes copepods, crab, lobster, cray-fish and prawn. Our group has developed a simple and selective electrochemical immunosensor based on methylene blue or hydroquinone derivative immobilized carbon nanomaterial modified electrodes for WSSV in raw infected shrimp tissue samples.1,2 Note that there are some conventional analytical techniques available for WSSV detection are based on polymerase chain reaction (PCR), DNA microarray, dot blot, western blot, enzyme linked immunosorbent assay (ELISA), affinity immunosensor, and antibody based microarray methods. Unfortunately, all these molecular techniques have their own limitations such as less sensitivity and high detection limit (~103 copies of its gene μ L−1), complicated offline preparation procedures, involvement of carcinogenic chemicals like ethidium bromide (in polymerase chain reaction (PCR)), requirement for well-equipped laboratories (for DNA assays), trained technicians and time consuming measurements (For ELISA 2–3 days‘ of time period required). This presentation covers preparation, characterization and shrimp-virus electrochemical immunosensor application.

References:

1. A.Natarajan, K.S.Shalini Devi, S.Raja and A.S. Kumar, Scientific Reports, 2017, 7:46169 2. M.Gandhi, D.Rajagopal, S.Parthasarathy, S.Raja, S.-T.Huang, A.Senthil Kumar, ACS Omega 2018, 3, 10823−10835.

Sellappan Senthilkumar

Associate Professor Department of Chemistry School of Advanced Sciences Vellore Institute of Technology (VIT) Vellore – 632014, INDIA.

S. Senthil Kumar was awarded his Ph.D. in Analytical Chemistry from University of Madras in the year of 2009. He did his post-doctoral research from Yonsei University, Seoul, South Korea in the year 2010-12 under the supervision of Prof. Dongil Lee. Currently he is working in VIT – Vellore as an Associate Professor. He is a fellow of the Academy of Sciences Chennai, since 2019. He has completed 3 funded projects like CSIR, SERB and DBT. She has published 35 reputed international journals including ACS Nano, Analytical Chemistry, Biosensors and Bioelectronics, Nanoscale and Scientific Reports.

Invited Lectures

Rationally Designed Ionic Liquids for Electrochemical Sensing

Sellappan Senthilkumar

Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology (VIT), Vellore-632014, India.

The rational design of materials and molecules with well-defined properties is a compelling need for realizing their industrial and technological applications. Ionic liquids have attracted a great deal of attention as environmentally benign media owing to the deck of properties extremely low vapour pressure, a wide liquid range, low flammability, high electrical conductivity, good solvent properties for a wide variety of compounds, high thermal stability, and a large electrochemical window that make it possible to use them in several applications including lower melting points, wide range of solubility, negligible vapour pressure, tunable miscibility and viscosity.1 These ILs comprising organic cations and inorganic anions offers plethora of combinations that can be tuned to achieve desired physicochemical properties for specific application. This tunability of ILs has rendered remarkable characteristics such as high ionic conductivity, non-flammability, biocompatibility and good electrochemical and thermal stability, which are desired for electrochemical applications. Accordingly, ILs have attracted worldwide recognition and opened the avenues for their application in biosensor, biomedical, biocatalysis and bioelectronics. In this talk, some of our recent attempts to design few IL molecules for the development of electrochemical sensors/biosensors will be presented. To begin with, we have synthesized IL molecules containing redox moieties and utilized them in both enzymatic and non-enzymatic biosensing.2 Further, we have synthesized functionalized ILs and employed these molecules as versatile platforms for the immobilization of biomolecules, followed by electrochemical biosensing. Our recent interest on tuning these ILs and exploring their applications in other areas of electrochemistry will also be discussed.

References:

1. Ghorbanizamani, F.; Timur, S., Anal. Chem. 2018, 90, 640-648. 2. Manoj, D.; Theyagarajan, K.; Saravanakumar, D.; Senthilkumar, S and Thenmozhi, K.; Biosens. Bioelectron. 2018, 103, 104–112.

S.K. ASHOK KUMAR

Associate Professor Department of Chemistry School of Advanced Sciences Vellore Institute of Technology Vellore-632014, Tamil Nadu, India E-mail: [email protected]

S. K. Ashok Kumar has awarded his PhD degree from Thapar University, Patiala, Punjab in the year 2006. His expertise is in Chemical Sensors (chromogenic, fluorogenic, potentiometric and voltammetric), Inorganic ion-exchange material (separation, ion sensing, and catalysis) and Nanocomposites and Porous carbon materials for water applications. He is a member of various professional Society like Life membership of chemical research society of India (LM 1277), Life membership of Indian Society for Electroanalytical Chemistry (ISEAC), Mumbai Dona Paulia, Goa and Life membership of Indian Science Congress, Kolkata. He has published more than 65 international journals, 1 review and 1 book chapter. He has completed 5 funded projects also.

Invited Lectures

New Thorium (IV) Selective Sensors

S.K. Ashok Kumar

Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore- 632014, Tamil Nadu

Thorium is an important metal for diverse applications such as manufacture of ceramics, carbon arc lamps, and catalyst in the chemical industry. It is also used as nuclear reactor fuels in the near future. Due to an extensive use of Th, contamination of air, water and soil components are likely. The UV- visible spectrophotometry, spectroflurometriy and potentiometric techniques are widely used due to its advantages such as cost-effectiveness, rapid detection, real-time monitoring, and ease of operation. Therefore, the sensing materials which are easy to synthesize and apply for a real-time monitoring of thorium in actual samples is the need of the hour. In this presentation, three different sensing materials such as N',N'-bis(-(2-hydroxynaphthalen-1-yl)methylene)-1,10-phenanthroline-2,9- dicarbohydrazide (S1), dibutyl (2-oxo-2-(quinolin-8-ylamino)ethyl) phosphinate (S2) and dibutyl (8- hydroxyquinolin-2-yl) methyl phosphonate (S3) developed as chromogenic, fluorogenic optode and potentiometric sensor for Th4+ ions. The lowest detection limit of Th (IV) by S1, S2 and S3 sensors were found to be 50 nM, 1.1 nM and 1.2 ppm respectively. All three sensors were successfully applied to estimate the Th4+ in real time samples such as monazite sand and gas mantles samples. The binding mechanism of sensing material with Th4+ ions was studied by 1H NMR, ESI-mass analysis and theoretical calculations.

S1 S2 S3

References:

1. Selva Kumar, R., Ashok Kumar, S. K., Vijayakrishna, K., Sivaramakrishna, A., Brahmmananda Rao, C. V.S., Sivaraman, N. and Sahoo, S. K. Inorganic Chemistry 2018, 57, 15270-15279. 2. Selva Kumar, R., Ashok Kumar, S. K., Vijayakrishna, K., Sivaramakrishna, A., Brahmmananda Rao, C.V.S., Sivaraman, N. and Sahoo, S. K. Analytical Methods 2018, 11, 1338-1345 3. Selva Kumar, R., and Ashok Kumar, S. K. Dalton Trans., 2019, 48, 12607-12614.

S. Sarveswari

Professor Department of Chemistry School of Advanced Sciences Vellore Institute of Technology Vellore-632014, Tamil Nadu, India

S. SARVESWARI is working as a Professor in the Department of Chemistry, School of Advanced Sciences, VIT-Vellore. He has completed the Doctoral degree from VIT-Vellore in the year of 2010. He has published more than 130 articles in various Scopus indexed International journals and published 3 monographs also. He has given 5 Ph.D degree and currently six students are pursuing their Ph.D under her supervision. She is serving as reviewer in more than 20 international journals and in couple of journals as editorial board member also.

Invited Lectures

Organic Small Molecules as Chemosensors

S. Sarveswari*

Department of chemistry, School of Advanced science, VIT-Vellore

Design and development of molecular probes for anion and cation recognition is an interesting topic of research till date. The organic small molecules found to serve as a chemo sensors. We are concentrating on cyanide, fluoride ion and mercury sensing. Mercury is one of the more toxic transition metal ions, which is a non-biodegradable environmental pollutant. It shows adverse effects on human health as well as living beings while consumed unknowingly. Generally mercury available in pollutants as oxidized form (Hg2+),element state (Hg0) and organic form methyl mercury (MeHg). Among this methylmercury can cause chronic diseases like central nervous system damages, brain, kidney, and liver damage. Similarly cyanide also associated with toxic effects. Absorption of cyanide, lead to various types of physiological disorders like convulsions, loss of consciousness and eventually death. Due to the serious health hazards associated with cyanide ion and mercury pollutants, we made an attempt to develop probes for the detection of them. Here in some simple organic molecules found confer this sensing property will be discussed.

Figure 1 Efficient sensing of pyrazole and diaminodicyano malononitrile derivatives

References:

1. Sarveswari, S; Jesin Beneto. A; Siva, A Sens. Actuators B Chem 2017, 245, 428-434. 2. Karuppusamy, P; Senthilvelan, J; Vijayakumar,V; Sarveswari, S Chemistry select 2020, 5, 49- 53.

Abstracts: Posters

P1: Synthesis, Characterisation and Nucleic acid Interactions of Phenanthroline Derivatives for Cytotoxicity Studies

Sourav De1, Selva Kumar R1, S K Ashok Kumar1*, Anbalagan Moorthy2

1Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, India 2Department of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, India

In this poster presentation, reporting design and synthesize of phenanthroline analogues for anticancer studies. Initially, the light absorbing and emission abilities of ligands and their binding interaction with CT-DNA and protein binding interaction were studied by using absorption and emission techniques respectively. It reveals that a strong absorption peak appeared around at 270 nm due to π-π* transitions of the phenanthroline moiety. The binding constant of ligands with DNA was found to be 104-105 M-1. The competitive displacement of ethidium bromide from DNA in the presence 4 -1 6 -1 of ligand study reveals that ligand exhibits an efficient binding affinity (KSV=10 M and Kapp=10 M ) indicating intercalation or groove binding of the ligands with CT-DNA which is further supported by viscosity studies. The gel electrophoresis analysis show that selected ligand (Phen-Hy) destroys plasmid DNA (10 kb) within 1.5 h of contact time due to intercalation mode. The MTT assay performed using two different cancer cell lines (HeLa and MDA-MB-231) and compared with normal HEK-293 cells. The obtained results reveals that Phen-Hy exhibits high potency and selectivity cytotoxicity profiles in both the cell lines.

Scheme 1: MTT cytotoxicity screening of phenanthroline ligand

References

1. Selvakumar, R.; Ashok Kumar, S. K.; Vijayakrishna, K.; Sivaramakrishna, A.; Brahmmananda Rao, C. V. S.; Sivaraman, N.; Sahoo, S. K.. Inorg. Chem. 2018, 57, 15270. 2. Siddiqui, S. A.; Potewar, T. M.; Lahoti, R. J.; Srinivasan, K. V.. Synthesis (Stuttg). 2006, 2006 (17), 2849–2854. 3. Siddiqui, S. A.; Narkhede, U. C.; Palimkar, S. S.; Daniel, T.; Lahoti, R. J.; Srinivasan, K. V. Tetrahedron 2005, 61, 3539–3546.

P2: Fluorescent Dipyrromethane Analogues as Potent Photoinduced Biosensors

Shiva Krishna Loke, Eswar Pagadala, Ravi Kumar Kottalanka*

Division of Chemistry, Department of Sciences and Humanities, VFSTR (Deemed to be University), Vadlamudi, Andhra Pradesh-522213, India

Recent times, fluorescence chemistry particularly, fluorescence imaging and indicators are essential tools in various fields of modern science and medicine, including clinical diagnostics, biotechnology, molecular biology and biochemistry, materials science, and analytical and environmental chemistry.1 Fluorescence materials have numerous applications such as information displays, memories, sensors, probes and photo-modulation.2 The fluorescence properties of chemical substrates indeed depend on the structure of their molecular assemblies. The simple structural and conformational changes play a major role in the precise analysis of biological functions and several biochemical reactions.3 However, certain molecular systems change their chemical structure and behaviour in response to external support such as chemical, electrical and light thereby modulating fluorescence properties. In particular, the photoinduced proton transfer (PPT) in dipyrromethane analogues such as photoenolization and phototautomerization are being special interest, since they were evolved as potent photoinduced biosensor capable of showing “fluorescence on” property at excited state via double proton transfer mechanism.4 In this context we synthesised three new dipyrromethane analogues i.e. [(Ph)(CH3)C{C4H2NH(CHO)}2] (DAA), [(Ph2)C{C4H2NH(CHO)}2] (DAB) and

[(Ph)(CH3)C(Ph3C-N=CH-C4H2NH)2] (DIDPM) in good yield (90%) via Vilsmeier-Haack and Schiff condensation method respectively. The systematic study of absorption, emission and lifetime of decay process by photoirradiation methods showed promising results. All the compounds were exhibiting large, Stokes shifted emissions at different wavelengths with good lifetime measurements in different solvents. Further, all the compounds were characterized by IR, 1H NMR, 13C NMR spectroscopy and DAA moiety was confirmed by single crystal X-ray diffraction analysis.

References:

1. N. Boens, V. Leen and W. Dehaen., Chem. Soc. Rev., 2012, 41, 1130–1172. 2. G. Mayer and A. Heckel, Angew. Chem.,Int. Ed., 2006, 45, 4900. 3. T. Kobayashi, T. Komatsu, M. Kamiya, C. Campos, M. Gonza´lez-Gaita´n, T. Terai, K. Hanaoka, T. Nagano and Y. Urano, J. Am. Chem. Soc., 2012, 134, 11153. 4. K. C. G. Sreedevi, A.P. Thomas, K. H. Aparna, R. Pradhan, M. L. P. Reddy, U. Lourderaj and A. Srinivasan., Chem. Commun., 2014, 50, 8667.

P3: Catalytic activity of the Gallium Metal Complexes Towards Ring-opening Polymerization of Cyclic Esters like ɛ-Caprolactone & Ethylene Brassylate

Eswar Pagadala, Shiva Krishna Loke , Ravi K. Kottalanka*

Department of Sciences and Humanities, Division of Chemistry, VFSTR (Deemed to be University), Guntur, Andhra Pradesh- 522 213, India.

The ring-opening polymerization (ROP) of cyclic esters like ɛ-Caprolactone & 1,4- Dioxacycloheptadecane-5,17-dione (ethylene brassylate) by discrete organic/inorganic initiators has been intensively investigated over the past 10 to 15 years1. Over the past five years, Ga (III) have attracted a growing interest towards ROP of cyclic esters, like ɛ-Caprolactone. Motivated by these results we successfully established highly potential Gallium metal complexes [(L1)2Ga-N(SiMe3)2](1)&

[(L1)2Ga (TBD)](2) (where L1=[Ph3CN=CH-C4H3NH] via one-pot slat metathesis route & ligand group exchange reactions under inert atmospheric conditions at ambient temperature. All these complexes were initially characterized by using spectroscopic and analytical techniques. The crystal structure of Gallium complex (1) was further confirmed by single crystal X-ray diffraction analysis. The ring- opening polymerization of ɛ-Caprolactone and ethylene brassylate was studied under various conditions and obtained polymers were characterized by using NMR analysis.

References:

1. Samuel Dagornea, Mickael Normand, Evgeny Kirillov, Jean-Francois Carpentier, Coordination Chemistry Reviews 2013, 257, 1869. 2. Pallabita Basu, Robi Sikdar, Tarun Kumar and Irishi N N Namboothiri. J. Euro Polymer. 2018, 108, 380.

P4: Structurally tuned Pd-Cu Systems as Efficient Catalysts for Ethanol Oxidation Reaction

P. C. Ashly1,2, Shreya Sarkar2,3, Sebastian C. Peter2,3*

1Department of Chemistry, St. Joseph’s College, 36, Lalbagh Road, Bangalore 560027, India 2New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India. 3School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.

The manipulation of the structural ordering in nanomaterial compounds are of great interest in tuning the surface properties with enhanced activity and selectivity towards various important catalytic processes. On another note, development of highly active and stable low cost Pt-free catalysts for ethanol electro-oxidation (EOR) in alkaline medium has drawn a lot of attention in recent years. Palladium based catalysts are on the forefront of this research. In this work, we have manipulated synthetic strategies for the formation of PdCu nanoparticles in various structural forms ranging from bimetallics, alloy and intermetallics, which in fact controlled the ordered-disordered arrangement of Pd and Cu atoms. The Pd-Cu catalysts with different chemical compositions were attempted by solvothermal method using NaBH4 as a reducing agent and were well characterized by XRD, XPS, ICP-OES, TEM and XAFS. The effect of different metal concentrations also utilized for the formation of heterostructures Cu/PdxCu1-x, PdxCu1-x/PdCu, Pd/PdxCu1-x and Pd/PdCu. The powder XRD and XAFS techniques were efficiently utilized to characterize these heterostructure models. The PdCu nanocatalyst with ordered structure (CsCl type) showed excellent catalytic activity compared to

PdxCu1-x alloy (Cu type) nanoparticles and heterostructures. The atomic ordering Pd and Cu in the PdCu intermetallic was the driving force for the enhancement in the catalytic activity with high mass activity (418.5 mA/mg Pd) compared to the other systems.

References:

1. Sarkar, S.; Jana,R.; Suchitra; Waghmare, U. V.; Kuppan, B.; Sampath, S.; Peter, S. C. Chem. Mater. 2015, 27, 7459. 2. Marakatti, V. S.; Sarma, S. Ch.; Joseph, B.; Banerjee, D.; Peter, S. C. ACS Appl. Mater. Interfaces. 2017, 9, 3602.

P5: Fluorescence Modulation on Imidazole-Tethered Anthracene Derivatives by Aromatic Acids

Munendra Pal Singh, Jubaraj B. Baruah*.

Chemistry Department. Indian Institute of Technology, Guwahati 781039, India.

Fluorescent molecules attached to chain containing multiple donor sites are conventionally used in molecular switches. Di-topic molecule that has two or more protonation sites as illustrated in Fig. 1a has scope to modulate emission properties by varieties of ways by stimulates. The example shown with an anthracene fluorophore will also be suitable for π- stacks among themselves or stacks with other π-systems adding extra feature to modulate emission properties. As a quest for such examples, we synthesized a di-topic compound 9-N-(3-imidazolylpropylamino) methylanthracene (HL). This compound has possibility to form salts at different proportions of weak acids such as nitro-phenols. We studied salts of nitro-phenols and carboxylic acids listed in the Fig. 1a. After differentiating the structures, we had studied their photo-physical properties in solid and solution states. An illustrative example where distinguishable ON-OFF Emissions feature is observed is shown in Figure 1b.

(a) (b) Figure 1: (a) A model receptor A to modulate fluorescence, the structures of HL and the partner acidic aromatic molecules and, (b) Emissions of HL on interactions with acidic aromatic molecules.

The fluorescence changes observed from solid-samples and in solution studies are correlated through analysis of data from quantum yields, life-time measurements.

Reference :

1. Singh, M. P.; Tarai, A.; Baruah, J. B. CrystEngComm. 2019, 21, 4898.

P6: Paper Based Self-assembled Tb3+ /Eu3+ Bis-lanthanide Ensemble: Probe for Differentiation of Structurally Similar Norfloxacin and Ofloxacin

Ananya Biswas, Uday Maitra*

Department of Organic Chemistry, Indian Institute of Science, Bengaluru

Tuning the ratio of the peaks of two metallic probes in a hetero-bi metallic ensemble is an effective way to read out the information about the chemical and environmental changes occurring in a system. This ratio-metric measurement modulates the ratio of two emission peaks and eliminates impacts of local probe concentration, sample environments, photo bleaching effects and power fluctuation of photon sources by a self-calibration method. Herein, we report the first example of a supramolecular self-assembled Tb3+/Eu3+ bis-lanthanide ensemble (Scheme 1) in which the energy transfer process from an antenna molecule (Norfloxacin or Ofloxacin ) to Tb3+ and Eu3+ takes place separately, along with a simultaneous Tb3+ to Eu3+ energy transfer process. The relative contributions of Tb3+ and Eu3+ in the composite time-resolved luminescence spectrum can be modulated by changing the sensitizer molecule. We have examined two structurally similar and frequently prescribed fluoroquinolone drugs, Norfloxacin and Ofloxacin. These drugs are otherwise difficult to distinguish by conventional methods (HPLC, UV or fluorescence) but can be differentiated by the designed Tb3+/Eu3+/cholate (4.5 mM/ 0.5 mM /15 mM) cocktail. The proposed bis-lanthanide cocktail in cholate (ch) gel matrix can be also useful for concurrent determination of the ratio of their concentrations in a mixture.

Scheme 1: Scheme of representation for the detection and differentiation of NFLX and OFLX

References:

1. Raz, S. R.; Bremer, M. G. E. G.; Haasnoot, W.; Norde, W. Anal. Chem. 2009, 81 (18), 7743. 2. Bhowmik, S.; Banerjee, S.; Maitra, U. Chem. Commun., 2010, 46, 8642. 3. Yao, J.; Zhao, Y. W.; Zhang, X. M. ACS Omega. 2018, 3 (5), 5754–5760

P7: Selective turn-on pyridoxal based chemosensor for visual and fluorescent detection of Zn(II) ion in DMF medium

K. A. Karthick, A. Tamilselvi*

PG & Research Department of Chemistry, Thiagarajar College, Madurai 625 009.

Zinc (Zn2+) is present in all forms of life and is the second most abundant transition metal in the human body after iron. Zn2+ is difficult to detect as it is spectrally silent.[1] In the present study, we have developed pyridoxal Schiff base ligand to selectively detect Zn2+ ions in the presence of various other metal ions. Pyridoxal phosphate, the active form of vitamin B6, is a co-enzyme in a variety of enzymatic reactions and its biological importance is well established. However, few reports on the development of chemosensors utilizing pyridoxal platforms.[2] Herein, we report synthesis of pyridoxal based Schiff base (HL), namely, 4-((3-(cyclohexylamino)propylimino)methyl)-5-(hydroxymethyl)-2- methylpyridin-3-ol and its selective recognition properties of Zn2+. It exhibited rapid response and unique selectivity of Zn2+ion in DMF medium.The ligand (HL) and its corresponding zinc complex have been synthesized and characterized by UV, FT-IR, NMR and ESI-MS technique. The optical and fluorescence properties of HL were investigated in DMF solvent. The binding stoichiometry of HL with Zn2+and binding constant calculation will also be discussed. The ligand may give insight into the design protocols required for the successful imaging of zinc ions.

HO N HO N N O N Zn(II) 2+ NH HO N Zn N

N O OH

Scheme 1. Sensing behavior of ligand (HL) towards Zn(II) ion.

References:

1. Nolan, E.M.; Lippard, S.J.; Acc. Chem. Res. 2009, 42, 193. 2. Thankaraj, A.; Ashok Kumar, S.K.; Suban, K.S.; Photochem. Photobiol. Sci. 2018, 17, 414.

P8: Synthesis of Carbazole Carboxylates and Angucycline-5-Aza Analogs via Hauser-Kraus Annulation-Ring Expansion-Ring Contraction Methods

Chenikkayala Sivasankara, Irishi N. N. Namboothiri*

Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India

The Hauser-Kraus annulation of sulfonylphthalide with N-protected 3-oleﬁnic oxindole carboxylates delivered the novel spiro-dihydronaphthoquinone-oxindoles.1 However, unprotected 3-olefinic oxindoles afforded carbazole carboxylates via oxazepine intermediates in a cascade manner in one pot. On the other hand, phenylethylidene oxindoles reacted with sulfonylphthalide to afford the angucycline-5-aza analogs. The cascade approaches follow Hauser-Kraus reaction-ring expansion- ring contraction methods to deliver the products in good to excellent yields.

Reference

1. Sivasankara, C.; Satham, L.; Namboothiri, I. N. N. J. Org. Chem. 2017, 82, 12939.

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P9: TBHP/Cu(OAc)2 catalyzed oxidation of 4,5-dihydro-1H-pyrazoles: A Facile approach for the preparation of 1H-pyrazoles

Kolla Sai Teja, Somanaboina Ramya, Bhimapaka China Raju*

Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.

Pyrazoles are an important heterocyclic compounds and play an prominent role in organic synthesis and medicinal chemistry.1 Celebrex, Viagra and Acomplia are important and commercially available pyrazole drug molecules. Further, pyrazole derivatives have possess various biological properties such as anti-tumor, anti-bacterial, anti-tubercular, anti-inflammatory, anti-diabetic, anti-depressant and anti-malarial activities. Due to the importance of these compounds, method development necessary for the preparation of pyrazoles. As a part of our ongoing research work on pyrazoles2-4 and synthesis of novel heterocyclic cmpounds, a simple and efficient oxidative method has been developed for the preparation of 1H-pyrazoles from 4,5-dihydro-1H-pyrazoles by using catalytic amount of

TBHP/Cu(OAc)2 as the catalyst (Scheme I). The method succesfully applied for the oxidation of dihydro pyrazole heterocyclic compounds to pyrazoles.

Scheme I

References:

1. Fustero, S.; Rosello, M. S.; Barrio, P.; Fuentes, A S. Chem Rev. 2011, 111, 6984. 2. Hariprasad, K. S.; Prasad, K. V.; Raju, B. C. RSC Adv. 2016, 6, 108654. 3. Dayakar, Ch.; Jyothi, D; Suman, P.; Raju, B. C. Synth Commun. 2015, 45, 1642. 4. Saidachary, G.; Prasad, K. V.; Divya, D.; Singh, A.; Ramesh, U.; Sridhar, B.; Raju, B. C. Eur J. Med Chem. 2014, 76, 460.

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P10: Stereoselective Total Synthesis of (-)-Diaportinol, (-)-Desmethyldiaportinol, (-)-Diaportinic acid and Peniisocoumarin

Aswathi Syam, Sunnappu Ranganayakulu, Rajendar Goreti *

School of Chemistry, IISER Thiruvananthapuram

We discuss about the total synthesis of (-)-Diaportinol (1), (-)-Desmethyldiaportinol (2), (-)- Diaportinic acid (3) and Peniisocoumarin (4). Diaportinol, Desmethyldiaportinol and Diaportinic acid were isolated from the cultures of Penicillium nalgiovense, which is ananamorph species of the genus of Penicillium with lipolytic and proteolytic activity. These molecules reported to possess potent cytotoxic activity. Peniisocoumarin was obtained from the fermentation of an endophytic fungus, Penicillium commune QQF-3. Peniisocoumarin exhibits cytotoxicity and enzyme inhibitory activities against α-glucosidase and Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB). For the synthesis of these four naturally obtained bioactive molecules, we began our synthesis by chiral pool strategy using commercially available D- malic acid.

Figure 1: Target molecules

References:

1. Cai, Runlin, et al. " Journal of natural products 81.6 (2018): 1376 2. Larsen, Thomas Ostenfeld, and Jens Breinholt. Journal of natural products 62.8 (1999): 1182. 3. Saeed, Aamer, and Muhammad Qasim. Natural product research 28.3 (2014): 185.

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P11: Tunable Phenothiazine derivative for specific fluorescent sensing of hypochlorite

Ummu habeeba A A, S anandan*

Department of Chemistry, National Institute of Technology Trichy

Rational development of probes for the sensing of hypochlorite anion (OCl-) in the biological system is a very significant topic. The presence of excess HOCl in the human body leads to permanent damages in the human internal system and sometimes leads to cancer as well. We have designed and synthesized phenothiazine based sensing probe TPT-3, which selectively detects the presence of OCl- anion at biological pH. The sensing probe molecule TPT-3 is a Schiff base molecule, with a phenothiazine donor fragment and dinitrophenylhydrazone as an acceptor fragment. Under fluorescence light, TPT-3 in DMF-phosphate buffer is not fluorescent and upon addition of NaOCl solution leads to intense green fluorescence at 488 nm, as given in figure 1. A gradual increase in fluorescent intensity is observed with an increasing amount of NaOCl. The emission of intense fluorescence in the presence of OCl- ion under UV light is expected to be due to the internal charge transfer (ICT). ICT mechanism is supported by the solvatochromic studies. In higher polar solvents TPT-3 exhibits red-shifted absorption peaks upon compared to relatively lower polar solvents. Further

theoretical data were provided to support the examination. 2

tpt- cho.csv tpt-3.+nocl.csv

tpt-3.csv

Absorbance (a.u.) Absorbance

0 300 400 500 600 700 Wavelength (nm)

Fig.1. Fluorescence spectra Fig.2. Fluorescence image of Fig.3. UV-Vis spectra of TPT-3 of TPT-3 with different TPT-3 with NaOCl anions

References:

1. Wu, D.; Chen, L.; Xu, Q.; Chen, X.; Yoon, J. . Acc. Chem. Res. 2019, 52 (8), 2158. 2. Cheng, X.; Jia, H.; Long, T.; Feng, J.; Qin, J.; Li, Z. A Chem. Commun. 2011, 47 (43), 11978. 3. Cheng, G.; Fan, J.; Sun, W.; Cao, J.; Hu, C. 2014, 1018.

103

P12: Tweaking the self-assembly of amyloid-like peptide fibres to hierarchical functional materials

Deepika Gupta,a Ashmeet Singh,a Ranjan Sasmal,b Jojo P. Joseph,a Sarit Agasti,b Asish Pala* aInstitute of Nano Science & Technology, Mohali, Punjab-160062 bJawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore 560064

Mimicking the out-of-equilibrium the self-assembly processes in nature is still a challenge for scientists, employing thermodynamically controlled bottom-up self-assembly. In the realm of bio- inspired material research, we take cue from amyloid beta sheet assembly and develop minimalistic peptide fragments based on amyloid core. Perfect control over length regimes of the self-assembled peptide nanofibers have been achieved through seeded living supramolecular polymerization. This, in turn, renders precise control of the supramolecular peptide fibers in different length regimes.1 Structural and temporal control to differentiate the pathway was exploited for photodimerizable peptide. It demonstrates the step-wise self-assembly to form nanoparticles, with eventual transformation into 1D nanofiber. Addition of host moiety with subsequent irradiation with UV light resulted to free-standing 2D nanosheets mediated by the host–guest interaction.2 Self-sorting is the ability of mixtures to recognize their identical counterpart over the other non-identical one and result in the formation of only selective and specific well-organized self-assembled structures rather that of all possible unspecific complex architectures. Peptides can undergo a range of non-covalent interactions and have the ability to recognize their own kind depending upon the side chain interactions and H bonding. Peptides fragments differing in chirality are designed and self-assembly pattern of the peptides with opposite chirality (L and D), are studied for molecular recognition. FRET technique is used to investigate self-sorting phenomenon.3 Orthogonal self-assembly was envisaged through seeded living polymerization through AFM imaging and ThT binding kinetics. Moreover, chirality driven self-sorted peptide fibers were visualized through super resolution microscopy.

Figure: Visualization of chirality driven self-sorted self-assembled nanofibers.

References:

1. Singh, A.; Joseph, J. P.; Gupta, D.; Sarkar, I. Pal, A.; Chem. Commun., 2018, 54, 10730. 2. Joseph, J. P.; Singh, A.; Gupta, D.; Miglani, C.; Pal, A. ACS Appl. Mater. Interfaces 2019, 11, 28213. 3. Gupta, D.; Sasmal, R.; Singh, A.; Joseph, J. P.; Agasti, S.; Pal, A. Under review.

104

P13: Enhanced Selectivity in Julia-Kocienski Reaction Using Quaternary Ammonium Salt

Sravya Surendran, Mintu Rehman, Nagendra.S, Rajendar Goreti*

School of Chemistry, IISER Thiruvananthapuram

A new methodology is designed to improve E-selectivity in Julia-Kocienski reaction using quaternary ammonium salt as an additive. We were indulged in the preparation of fragments necessary for the total synthesis of rickiols, which uses Julia-Kociensky reaction as one of the key steps to prepare E- selective olefin. The olefination of mannitol aldehyde by Julia-Kocienski reaction for E-olefin suffered with poor selectivity, this may attributed due to chelation effect of substrate. Systematic investigations to counter chelation effect by the use of highly non-coordinating counter cation leads to this new methodology. Use of quaternary ammonium salts enhanced the selectivity to achieve targeted E- isomer. Amongst different quaternary ammonium salts, tetrabutylammonium bromide (TBAB) worked most efficiently to provide highest selectivity

References:

1. Pospíšil, Jiří. Tetrahedron Letters 52.18 (2011): 2348. 2. Baudin, J. B., et al." Bulletin de la Société chimique de France 130.6 (1993): 856. 3. Blakemore, Paul R, Journal of the Chemical Society, Perkin Transactions 1 23 (2002): 2563.

105

P14: Effective removal of Hg(II) from aqueous solution using petal-like MoS2 nanosheets

P. Ragini, Sambandam Anandan*

Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Tiruchirappalli-620 015, India

Few-Layered MoS2 nanosheets were synthesized via a surfactant-assisted hydrothermal method and utilized them as an efficient adsorbent for the removal of mercury from aqueous solution. The synthesized MoS2 nanosheets showed petal-like morphology as confirmed by SEM and TEM analysis. Having high stability and negative zeta potential makes it suitable for the fast adsorption of mercury from aqueous media. The adsorption efficiency of the adsorbent was investigated as a function of pH, contact time and adsorbent dose. The kinetics of adsorption and reusability study of the adsorbent was also performed. A pseudo-second-order kinetics for mercury adsorption was observed. As prepared MoS2 nanosheets showed 87 % mercury removal efficiency whereas regenerated adsorbent showed 80 % removal efficiency. The maximum adsorption capacity of the adsorbent was found to be 289 mg g-1 at room temperature.

Schematic diagram of the synthesis process of MoS2 nanosheets and adsorption of mercury on its surface.

References:

1. F. Jia, Q. Wang, J. Wu, Y. Li and S. Song, ACS Sustain. Chem. Eng., 2017, 5, 7410. 2. F. Jia, X. Zhang and S. Song, Phys. Chem. Chem. Phys., 2017, 19, 3837. 3. A. Gupta, V. Arunachalam and S. Vasudevan, J. Phys. Chem. Lett., 2015, 6, 739.

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P15: Design, synthesis and evaluation of new 1,5-benzodiazepines as a versatile pharmacophoric unit for the treatment of Cancer and Tuberculosis

Sinthiya Gawandi a, b, Shrinivas Joshic, Fateh V Singhd, Vidya Desai a,b*. aDepartment of Chemistry, Dnyanprassarak Mandal’s College & Research Centre, Assagao, Bardez 403507, India. b Goa University, Taleigao, Panaji 403206, India. c Novel Drug Design and Discovery Laboratory, Department of Pharmaceutical Chemistry, S.E.T.’s College of Pharmacy, Sangolli Rayanna Nagar, Dharwad 580 002, Karnataka, India. dDepartment of Chemistry, Vellore Institute of Technology, Chennai Campus, Tamil Nadu, India. .

With the growing emergence for the development of novel drug targets as an antidotes for highly dreaded diseases like cancer and tuberculosis a series of differently substituted new 2-Methyl-2,4- diphenyl-2,3-dihydro-1H-benzo[1,5]diazepine derivatives of potential biological significance were synthesized by condensation of o-phenylenediamine with differently substituted acetophenones using catalytic amount of thiamine hydrochloride, a biocatalyst, under solvent free reaction conditions. The in-vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv strains have been evaluated for selected compounds. The results revealed that the compounds showed moderate anti tubercular activity against Mycobacterium tuberculosis H37Rv strains. In-vitro cytotoxicity studies have been examined against couple of cancer cell lines (HeLa and HEPG2) and normal human cell line

HEK-293. Compound 3x was found to be influential against both the cell lines with IC50 values of 0.067± 0.002 µM against HeLa and 0.087± 0.003 µM against HEPG2 cell line, having activity as compatible to the standard drug Methotrexate. It was also potent against Mycobacterium tuberculosis

H37Rv strains with IC50 value of 6.25 µg/mL. All the screened compounds were proved to be nontoxic with higher value of selectivity index.

R1 O N NH2 Biocatalyst + 2 R R2 NH2 2 N R1 solvent free H R1

27 derivatives of 1,5-benzodiazepines .

References:

1. Trenton, A.; Currier, G. Prim. Care Companion J. Clin. Psychiatry. 2001, 3(6), 236. 2. Mazimba, O.; Molefe, T. Int. J. Chem. Studies, 2015, 3, 46. 3. Chen, L.; Bao, S.; Yang, L.; Zhang, X.; Li, B.; Li, Y. Res. Chem. Intermed. 2017, 43, 3883. 4. Salve, P.; Mali, D. Int. J. Pharm. Bio. Sci. 2013, 4, 345.

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P16: Maximization of Photocatalytic and Photoelectrochemical Performance by Bi2WO6/TiO2- Ag Ternary Composite

Jothivenkatachaam K,1* Kavinkumar V,1 Sriramkumar M,1 Moscow S,1 Yen-Pei Fu2

1Material Research Laboratory, Department of Chemistry, UCE-BIT Campus, Anna University, Tiruchirappalli, Tamil Nadu 620024, India 2Department of Materials Science and Engineering, National Dong Hwa University, 97401 Taiwan

Utilization of free and green solar energy for the purification of polluted water and energy production

(H2 & O2 evolution) using semiconductor based metal oxide photocatalysis is a most hopeful 1 technique. Here, we have successfully synthesized ternary Bi2WO6/Ag/TiO2 photocatalyst via CTAB assisted hydrothermal and simple chemical reduction method. As expected, co-induction of TiO2 and

Ag NPs on the surface of Bi2WO6 nanoplate, which is observed by the TEM images. From the XRD patterns, the tetragonal for TiO2 and FCC for Ag phase peaks were gradually increased in the Bi2WO6 orthorhombic structure when increasing the concentration of precursor. Since, TiO2 as a conventional semiconductor with a unique properties of low cost, non-toxic and mechanical stability which also commercialized, however it couldn‟t active under solar light. Hence, visibly active bismuth (III) based materials extensively attracted for the photocatalytic pollutant degradation and water splitting.

Bi2WO6/TiO2-Ag composite attained highest performance compared with bare Bi2WO6 and TiO2 materials due to the reduction of electron/hole recombination and increasing the absorption capability by the SPR effect.2,3

Fig. P-XRD pattern (a) and UV-Vis DRS spectroscopy (b) of as-prepared materials

References:

1. Veerappan, K.; Dhayanantha, P. J.; Atul, V.; Kandasamy, J,; and Yen-Pei, F.; New J. Chem., 2019, 43, 9170. 2. Arjunan, N.; Henry, L. J.; Karuppannan, R.; Kandasamy, R.; Kulandaivel, J.; and Kandasamy, J.; Journal of Photochemistry & Photobiology, B: Biology, 2015, 153, 412. 3. Veerappan, K,; Atul, V,; Sriramkumar, M,; Sanath, K,; Kandasamy, J,; and Yen-Pei, F,; Dalton Trans., 2019, 48, 10235.

108

P17: All Solid State Rechargeable Proton Battery

Neethu C D, Muhammed Musthafa O T*

Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune

Electric energy is an inevitable factor in our day to day life. Starting from our basic to industrial needs requires electric energy. Due to industrial revolution energy conversion from non-renewable resources (fossil fuels) rose exponentially. Even in this 21st century, we rely mostly on non-renewable resources for large scale electricity production, which invariably emit greenhouse gases into the atmosphere at an alarming rate to be neglected1. This add-up to global pollution as well as rise in global mean temperatures. In this context, it was unambiguously decided to limit the global warming temperature to 1.5oC during the UN conferences on climate change held in Paris on December 2015 and the same voice was echoed in the subsequent years. To achieve this target we need to focus on electricity production from the renewable energy resources2, utilization of which is greatly limited by their characteristic fluctuations. This existing gap between availability and demand can be filled with potential zero emission technologies such as batteries, fuel cells, supercapacitors and solar cells. Recently, we have successfully demonstrated a rechargeable hydrogen battery based on the cleanest energy carrier molecule hydrogen; by utilizing proton coupled electron transfer in hydrogen storage molecule3. Working principle of this battery includes hydrogenation and dehydrogenation of hydrogen storage molecules during discharging and charging respectively. However, we utilised the gaseous hydrogen as the anode, which limits its practical usage. In order to overcome this we propose an all solid state rechargeable proton battery by utilizing the principle of intercalation/de-intercalation of protons in transition metal oxides and proton-coupled electron transfer in hydrogen storage molecules. Electrochemical, spectroscopic, and spectroelectrochemical analysis evidence the participation of protons during charge-discharge chemistry and extended cycling. In an era of anthropogenic global climate change and paramount pollution, a battery concept based on protons demonstrates distinct progress in the sustainable energy landscape.

References:

1. Bruce, P. G.; Freunberger, S. A.; Hardwick, L. J.; Tarascon, J.-M. Nat. Mater. 2011, 11, 19. 2. Chu, S.; Cui, Y.; Liu, N. Nat. Mater. 2016, 16, 16. 3. Neethu, C.D.; Thimmappa, R.; Manzoor Bhat, Z.; Devendrachari, M. C.; Kottaichamy, A. R.; Gautam, M.; Shafi, S. P.; Thotiyl, M. O. J. Phys. Chem. Lett. 2018, 9 (10), 2492.

109

P18: Injectable Silk Hydrogel for Sustained Insulin Delivery in Diabetic Rats

Biswanath Maity, Sourav Samanta, Shradhya Sarkar, Shadab Alam, Thimmaiah Govindaraju*

Bioorganic Chemistry Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre of Advanced Scientific Research (JNCASR), Jakkur P.O., Bengaluru – 560064, Karnataka, India

Diabetes is a chronic disease affecting over 400 million people worldwide. Inadequate production of insulin due to loss of beta cells or insulin resistance within the body imbalances the glucose homeostasis, subsequent increased of blood glucose level. The conventional treatment involves repeated subcutaneous insulin injections to maintain the physiological glucose homeostasis. However, continuous and multiple subcutaneous injections are associated with poor patient compliance and local amyloidosis of insulin, which can be overcome with sustained insulin delivery. In this context, we have designed and formulated an injectable silk fibroin hydrogel (iSFH) for sustain insulin delivery over a continuous time period under diabetic conditions. Interestingly, the subcutaneous injection of insulin encapsulated iSFH (insulin-iSFH) in diabetic T1DM Wister rat (induced by streptozotocin) released the insulin in a controlled way and restored physiological glucose homeostasis up to 4 days. The biocompatible and biodegradable nature makes iSFH a potential and active-drug delivery system for the sustained delivery of insulin.

References:

1. Zimmet, P.; Alberti, K. G.; Magliano, D. J.; Bennett, P. H. Nat. Rev. Endocrinol. 2016, 12, 616. 2. Manchineella, S.; Thrivikraman, G.; Khanum, K. K.; Ramamurthy, P. C.; Basu, B.; Govindaraju, T. Adv. Healthc. Mater. 2016, 5, 1222. 3. Datta, L. P.; Manchineella, S.; Govindaraju, T. Biomaterials, 2020, 230, 119633. 4. Manchineella, S.; Govindaraju, T. In stimuli-responsive drug delivery systems, Singh, A.; Amiji, M. M. Eds.; RSC publisher, 2018, 317. 5. Manchineella, S.; Thrivikraman, G.; Basu, B.; Govindaraju, T. ACS Appl. Mater. Interfaces 2016, 8, 22849.

110

P19: Facile Bile Salt-Induced Synthesis of Mesoporous MnO2 Nanoflowers: Applications in dye removal, oxidation and supercapacitors

Ajay Kumar, Dillip G.R., A.J. Bhattacharyya, Uday Maitra*

Department of Organic Chemistry, Indian Institute of Science, Banaglore, 560012

MnO2 is an important functional oxide with wide applications such as in the oxidation of benzylic and allylic alcohols, as an electrode material for supercapacitors, in the removal of dyes etc. In this chapter, we demonstrated a simple, bile-salt induced synthesis of mesoporous (MP) MnO2 at neutral pH from potassium permanganate. The physical properties of the synthesized MnO2 was found to be dependent on the reaction temperature. This porous material with high surface area was used for the adsorption of cationic organic dyes. Because of the exceptionally large surface area, we observed significantly higher dye adsorption, and higher yields in standard oxidation reactions compared to commercial samples of MnO2. Some of the results will be presented in this poster. R

Methylene blue HO R'

Oxidation of benzylic Dye adsorption alcohols

R O R' 18

References:

1. Kim, H.; Wathanaphanit, A.; Saito, N. ACS Sustainable Chem. Eng. 2017, 5, 5842. 2. Hu, X.; Shi, L.; Zhang, D.; Zhao, X.; Huang, L.; RSC Adv. 2016, 6, 14192. 3. Harfenist, M.; Bavley, A.; Lazier, W. A. J. Org. Chem., 1954, 19, 1608.

111

P20: A Facile Approach for the Regioselective Preparation of 3-Halo-2H-Chromenones, 3-(2- haloacetyl)-2H-Chromenones and Halogenated 2H-Chromenone Natural Products Promoted by Oxone and NaX

Vanammoole Lakshmireddy, Vaidya Jayathirtha Rao, Bhimapaka China Raju*

Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.

2H-Chromenones are bio-active natural products and privileged compounds.1 2H-Chromenones exhibit various biological and pharmaceutical properties. Regioselective halogenation is the fundamental and potential reaction for the preparation of halogenated compounds. As part of our ongoing research on Regioselective halogenation, we have reported acetanilides, benzanilides, sulphonamides and heterocyclic compounds with oxone and NaCl/NaBr.2-4 The present work describes the preparation of 3-halo-2H-chromenones, 4-substituted 3-halo-2H-chromenones and 3- (2-haloacetyl)-2H-chromenones (Scheme I) by the halogenations of 2H-chromenones with commercially available NaCl/NaBr and oxone. We also screened the various ammonium halides for the present reaction and found chloride and bromide were facilitated the halogenations reactions. Further, the method has been successfully applied for the preparation of pharmaceutically important halogenated 2H-chromenone natural products such as Marmesin, Lomatin, Columbianetin, and Decursinol. The present approach is simple and provides high yields of the target compounds.

Scheme I

References:

1. Cao, D. Liu, Z.; Verwilst, P.; Koo, S.; Jangjili, P.; Kim, J. S.; Lin, W. Chem. Rev. 2019, 119, 10403. 2. Bikshapathi, R.; Prathima, P. S.; Rao, V. J. Green Chem. 2017, 19, 4446. 3. Reddy, V. L.; Prathima, P. S.; Rao V. J.; Bikshapathi, R. New J. Chem. 2018, 42, 20152. 4. Reddy, V. L.; Veera, Y. N.; Reddy, T. J.; Rao V. J.; Raju, B. C. Asian J. Org. Chem. 2019, 8, 1380.

112

P21: Reductive Ring Opening of Aroyl and Nitro-Substituted and γ-Butyrolactone fused DonorAcceptor Cyclopropanes

S. Thangamalar, V. John Tamilarasan, K. Srinivasan*

School of Chemistry, Bharathidasan University, Tiruchirappalli-24.

Donor-acceptor (D-A) cyclopropanes (DACs) have received a great deal of attention in recent years owing to their enormous synthetic potential.1 The ring opening and formal cycloaddition reactions of D-A cyclopropanes constitute the basis for the majority of their synthetic applications. Our research group has developed an expedient procedure for the access of aroyl and nitro-Substituted D-A cyclopropanes as well as for γ-butyrolactone fused D-A cyclopropanes and is exploring their synthetic utility.2,3 In continuation of our efforts, we have found that these cyclopropanes undergo reductive ring opening upon catalytic hydrogenation or treatment with Zn/AcOH in alcoholic solvents to give ring opened products (Scheme 1). Accordingly, aroyl-substituted D-A cyclopropanes 1 when treated with Zn/AcOH in MeOH give aroyl-substituted arylethylmalonates 4, nitro-substituted D-A cyclopropanes 2 upon catalytic hydrogenation using H2/Pd/C in EtOH afforded arylethylmalonates 5 and γ- butyrolactone fused D-A cyclopropanes 3 upon treatment with Zn/AcOH in MeOH furnished 3,4,5- trisubstituted γ-butyrolactones 6. The products are not only versatile synthetic precursors for other compounds, but also difficult to prepare by other methods. In the poster, we will present the details of ring opening products obtained in the current studies and their synthetic applications.

Scheme 1

References:

1. Schneider, T. F.; Kaschel, J.; Werz, D. B. Angew. Chem., Int. Ed. 2014, 53, 5504. 2. Selvi, T.; Srinivasan, K. Isr. J. Chem. 2016, 56, 454. 3. (a) Tamilarasan, V. J.; Srinivasan, K. J. Org. Chem. 2019, 84, 8782. (b) Tamilarasan, V. J.; Srinivasan, K. Eur. J. Org. Chem. doi:10.1002/ejoc.201901639.

113

P22: OXALIC ACID CATALYSED OXIDATION OF PHENOXY ACETICACID BY QUINALDINIUM DICHROMATE-A KINETIC STUDY

T. Selvakumar, M. Venkatapathy, K. Anbarasu*

Department of Chemistry, Arignar Anna Govt. Arts College, Musiri – 621 211.

Oxidation of phenoxyaceticacid by quinaldinium dichromate (QnDC) in the presence of perchloric acid and oxalic acid has been studied in 50% (v/v) aqueous acetic acid medium. The reaction shows unit order dependence each with respect to oxidant and oxalic acid. The order with respect to substrate is fractional and hydrogen ion concentration is inverse fractional. The rate of oxidation increases with increase in the percentage of acetic acid and increase the ionic strength has negligible effect on the reaction rate. Number of electron transferred during the oxidation process has also determined. The thermodynamic and activation parameters have been calculated using Eyring‟s plot. From the kinetic observations, the reaction mechanism and rate law has been proposed.

Reference:

1. Degirmenbasi, N. and Ozgun, B 2004, „QuinaldiniumFluorochromate and Quinaldinium Dichromate: Two New and Efficient Reagent for the Oxidation of Alcohols‟, Monatshefte fur Chemie, vol. 135, no. 4, pp. 407-410.

2. Koelsch, C. F 1931, „The Identification of Phenols‟, Journal of American Chemical Society, vol. 53, no. 1, pp. 304-305.

114

P23: Direct Role of Methylmercury on alkylating DNA Lesion and its Remediation Strategy using Functional Mimic of Organomercurial Lyase MerB

Ranajit Das; Ramesh Karri; Gouriprasanna Roy*

Department of Chemistry, Shiv Nadar University, NH91, Dadri, Gautam Buddha Nagar, Uttar Pradesh–201314, India

Methylmercury (MeHg+) is a potent neurotoxin that bio-accumulates at high levels in food chains, and thus poses a significant health risk to human health. It is known to inhibit several important antioxidant enzymes and also reduce the concentration of endogenous thiols like cysteine and glutathione in tissues, and thereby increases the production of reactive oxygen species which lead to the oxidative damage of biomolecules including DNA and protein.2 The high potency of MeHg+ in producing DNA damage compared to inorganic mercury Hg2+ in tissues is often recognized due to its striking ability to easily cross the cellular membranes including the placental and blood-brain barriers. However, contrary to its recognized indirect role on oxidative DNA damage, in this poster for the first time we will show the direct effect of MeHg+ on alkylative DNA damage in the cellular system, in addition to the oxidative DNA damage, which may account for its high cytotoxicity of organomercurials compared to inorganic mercury.On the other hand, microbial methylation of inorganic mercury Hg2+ is the major source of MeHg+ in nature and therefore, the demethylation of MeHg+ is an extremely important process for maintaining the net MeHg+ levels in the environment. In nature, mercury-resistant bacteria having mer operon detoxify MeHg+ by producing a series of mer proteins including organomercurial 2+ 3 lyase MerB that catalyzes the protolytic Hg–C bond cleavage and produces Hg and CH4. In this poster, we will report a synthetic molecule which showed remarkable ability to protolytically cleave Hg–C bonds of a wide variety of R–Hg–X molecules, including MeHg-DNA adduct (R = alkyl or aryl; X = Cl, I, SPh or nucleoside) in the absence of exogenous thiols under mild conditions and thereby help to protect DNA from alkylative or oxidative damage caused by MeHg+.

References:

1. Clarkson, T. W.; Magos, L. Crit. Rev. Toxicol. 2006, 36, 609. 2. Pieper, I.; Wehe, C. A.; Bornhorst, J.; Ebert, F.; Leffers, L.; Holtkamp, M.; Höseler, P.; Weber, T.; Mangerich, A.; Bürkle, A.; Karst, U. Metallomics 2014, 6, 662. 3. Omichinski, J. G. Science 2007, 317, 205–206 Wahba, H. M.; Stevenson, M. J.; Mansour, A.; Sygusch, J.; Wilcox, D. E.; Omichinski, J. G. J. Am. Chem. Soc. 2017, 139, 910.

115

P24: A hydrazide based reversible probe for Al3+ and sequential detection of PPi, ATP and ADP in semi-aqueous medium

Sagarika Mishra, Sayed Muktar Hossain, Akhilesh Kumar Singh*

School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, 751007, India.

Development of fluorescence chemosensors targeting multiple analytes recognition has led to a huge surge of interest among researchers. Such systems are gaining wide attention due to their quick response and cost effectiveness. Aluminum is one of the metals widely used in cookware, paper industry, textile industry, water purification techniques and in the production of light alloy. However, accumulation of aluminum in body results in the deposition of aluminum in different cells and tissues leading to diseases like Al-related bone disease (ARBD), dementia, Alzheimer‟s disease, 2- etc. Similarly design of sensors for phosphate anions and derivatives such as HPO4 , pyrophosphates, adenosine triphosphate (ATP) and adenosine diphosphate (ADP) have dragged special interest due to the vital roles played by these species in biological processes. Among other detection techniques fluorescence spectroscopy stands apart, because of its simplicity, cost effectiveness, sharp recognition, rapid and real time analysis and visual detection. A hydrazide based

Schiff base ligand, H2L has been synthesized and characterized by all spectroscopic techniques. In 3+ this presentation selectivity and specificity of H2L (sensor 1) towards Al in semi aqueous medium

(DMF/H2O mixture) by exhibiting a drastic increase in the fluorescence intensity will be discussed. The L-Al3+ complex (sensor 2) generated in the solution acts as a sensor to sequentially detect pyrophosphate groups present in inorganic pyrophosphate, ATP and ADP among other anions by turning off the fluorescence. The results of emission studies, reversibile behavior, response to variation in pH, life time and quantum yield will be highlighted.

3+ 2- Fig. 1. Logic Gate for Al and P2O7 as chemical inputs and fluorescence emission as output.

References:

1. Wu, D.; Sedgwick, A. C.; Gunnlaugsson, T.; Akkaya, E. U.; Yoon, J.; James, T. D., Chem. Soc. Rev. 2017, 46 (23), 7105-7123. 2. Wang, B.; Xing, W.; Zhao, Y.; Deng, X Environ. Toxicol. Pha. 2010, 29 (3), 308-313. 3. Rai, A.; Singh, A. K.; Tripathi, K.; Sonkar, A. K.; Chauhan, B. S.; Srikrishna, S.; James, T. D.; Mishra, L Sensor Actuat B-Chem 2018, 266, 95-105.

116

P25: Operando Generated Intermetallic Ni3In as a Catalyst for the Selective Conversion of CO2 to Methanol

Arjun Cherevotan, Jithu Raj, Soumyabrata Roy, Sebastian C. Peter*

New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore- 560064.

Amplified emission of carbon dioxide (CO2) due to anthropogenic activities is identified as the main root of intensified global warming and climate change in recent years. The best way out suggested is to hydrogenate CO2 back to fuel and is also identified as a “single stone two bird” approach to settle 1, 2 both hiking energy demand and CO2 emissions. Thermocatalytic routes of hydrogenation is catalysed in industries by Cu/ZnO/Al2O3 (CZO) catalysts which utilizes high pressure of 50-100 bar and 230-300°C.3 In this work we have used a rationale way of designing the catalysts for the efficient conversion of CO2 to methanol. The well-known methanation catalyst nickel has been tuned with the introduction of inactive indium for this purpose. We have selected the most stable intermetallic Ni7In3 supported on SBA-15, which was synthesized via incipient wetness impregnation. The optimized reaction conditions in the thermochemical pathway favoured the in-situ transformation of Ni7In3 to

Ni3In (scheme), which favoured the conversion of CO2 to methanol instead of methane. This ordered arrangement of atoms with the isolation of the active site nickel and electronegativity difference between Ni and In are attributed to shift the mechanism towards methanol compared to methane in the case of Ni/SBA-15.

Scheme: In-situ transformation of Ni7In3 to Ni3In during the catalytic CO2 hydrogenation.

References:

1. Goeppert, A.; Czaun, M.; Jones, J. P.; Prakash, G. K. S.; Olah, G. A., Chem Soc Rev 2014, 43 (23), 7995. 2. Roy, S.; Cherevotan, A.; Peter, S. C., ACS Energy Letters 2018, 3 (8), 1938. 3. Kattel, S.; Liu, P.; Chen, J. G., Journal of the American Chemical Society 2017, 139 (29), 9739.

117

P26: Substituent effect on second order non-linear optical properties of Y-shaped ferrocene conjugated imidazole based D-π-A chromophores

Prabu Selvam, Nallasamy Palanisami*

Department of Chemistry, School of Advanced Sciences, Vellore Institute of technology, Vellore 632014, Tamil Nadu, India. )

The donor-π-acceptor based chromophores have second order non-linear optical (NLO) properties is an exciting discipline with important applications such as optical data storage, telecommunications, optical switch, electro-optic modulator and NLO bioimaging.1,2 The donor-π-acceptor based bis- ferrocenyl imidazole chromophores were synthesized and characterized by analytical and spectroscopic techniques such as FT-IR, 1H and 13C NMR, and ESI mass. The structure is further confirmed by single crystal X-ray diffraction studies. The solvatochromic studies reveals that nonpolar to polar solvents enhance the redshift for all the chromophores. The redox wave in electrochemical studies of the chromophores evidenced the electron transfer ability of the bis- ferrocenyl imidazole chromophores. The second-order nonlinear optical (NLO) properties were determined by the Electric Field Induced Second Harmonic Generation (EFISHG) technique working in CHCl3 solution with an incident wavelength of 1907 nm. The µβ1907 values of bis-ferrocenyl imidazole chromophores and will be presented. Figure: NLO-active Y-shaped chromophores.

References:

1. Prabu, S.; David, E.; Viswanathan, T.; Thirumoorty, K.; Panda, T.; Dragonetti, C.; Colombo, A.; Marinotto, D.; Righetto, S.; Roberto, D.; Palanisami, N. Dalton Trans. 2020, DOI:10.1039/C9DT03637G. 2. Prabu, S.; David, E.; Viswanathan, T.; Jinisha, J. S. A.; Malik, R.; Maiyelvaganan, K. R.; Prakash, M.; Palanisami, N. J. Mol. Struct., 2020 (1202), 127302.

118

P27: Stress Induced Electronic Structure Modulation of Mn-incorporated Ni2P Leading to Enhanced Activity for Water-Splitting

Shreya Sarkar, Lakshay Dheer, C. P. Vinod, Ranjit Thapa, Umesh V. Waghmare, Sebastian C. Peter

New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, Bangalore- 560064

The cornerstone of the emerging hydrogen economy is hydrogen production by water electrolysis with concomitant oxygen generation. Although transition metal phosphides belong to a premier class of water splitting electrocatalysts, their performance is not comparable to noble metals. Including a third element to them can facilitate tuning of the crystalline and electronic structure and hence, improve the electrocatalytic properties. In this work, Mn doped Ni2P with varying ratios of Mn and Ni has been explored as excellent catalysts for efficient water splitting. A complete cell made of the best catalyst -2 Ni1.5Mn0.5P electrodes exhibits a low voltage of 1.7 V at a current density of 10 mAcm as a result of low onset potentials for HER (65 mV) and OER (1.45V). The high performance of Ni1.5Mn0.5P can be accredited to enhanced electrical conductivity, induction of tensile stress, enhanced electrochemical surface area, increased electric dipole due to Mn incorporation. Density functional theory (DFT) demonstrates the intricately low hydrogen adsorption energy value for Ni1.5Mn0.5P accounting for its highest HER activity whereas, for OER high affinity for oxygen and the presence of M-O species on pristine and Mn-substituted Ni2P portrays the enhanced OER activity upon Mn substitution.

References:

1. Sarkar, S.; Dheer, L.; Vinod, C. P.; Thapa, R.; Waghmare, U. V.; Peter, S. C., 2020, (Manuscript under review in ACS Applied Energy Materials).

119

P28: Ferrocene/ Non-Ferrocene Conjugated X-shaped Borasiloxanes for Luminescence and Non-Linear Optical properties

Viswanathan Thamodharan, Nallasamy Palanisami*

Department of Chemistry, School of Advanced Sciences, Vellore Institute of technology, Vellore - 632014, Tamil Nadu, India.

Materials with second-order nonlinear optical (NLO) properties are of great interest since they can be used for various important applications such as optical communication, optical data processing and storage, and electro-optical devices. In this aspect, the donor-acceptor ferrocene/non ferrocene conjugated X-shaped borasiloxanes were synthesized and characterized by various spectroscopic techniques such as FT-IR, NMR, and HRMS. The charge transfer ability of both the borasiloxanes were tested using solvatochromic studies and low fluoresence to enhanced fluoresence intensity was achived by Aggregation-induced emission (AIE) studies through the principle of restriction of intramolecular rotations (RIR) using THF: H2O mixture. The second-order nonlinear optical (NLO) properties were determined by the Electric Field Induced Second Harmonic Generation (EFISHG) technique working in DMF solution with an incident wavelength of 1907nm. The X-shaped ferrocene −48 conjugated borasiloxane shows enhanced NLO µβ1907 -435 × 10 esu. Further, these experimental results were supported by density functional theory (DFT) at B3LYP/6-31+G** level of theory and will be presented.

Figure 1. Chemical structure of X-shaped ferrocenyl/non-ferrocenyl borasiloxanes.

References:

1. Gopalakrishnan, M. Viswanathan, T. David, E. Thirumoorthy, K. Bhuvanesh, N. Palanisami, N. New J. Chem. 2019, 43, 10948-10958. 2. Prabu, S. David, E. Viswanathan, T. Thirumoorthy, K. Panda, P. Dragonetti, C. Colombo, A. Marinotto, D. Stefania Righetto, S. Roberto, D. Palanisami, N. Dalton Trans.,2020. (Accepted).

120

P29: Y-shaped thiophene conjugated quinoxaline derivatives for photophysical and biological applications

Ayilam Viswanathan Rajalakshmi, Nallasamy Palanisami*

Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore.

Thiophene derivatives have attracted wide attention of researchers as it has various applications such as fluorescent1, metal ion sensors, anti-bacterial, solar cell and opto-electronic devices. Due to their ease of synthesis and they are chemically stable, thiophene is one of the most studied heterocycles2. In this aspect, we have synthesized Y- shaped thiophene conjugated quinoxaline derivatives 1-7 and were characterized using analytical and spectroscopic techniques. All these derivatives exhibited excellent fluorescence in solid as well as in solution state. Among them, the nitro substituted derivative showed good aggregation induced emission (AIE)3 due to the formation of nano-aggregates which was further characterized using DLS and SEM. These derivatives can also be used as potential candidates for DNA-binding applications as well as for cancer cell-line studies and will be presented.

The synthetic route of thiophene conjugated quinoxaline derivatives

References:

1. Kaur, G., Kaur, N., Sensors and Actuators B: Chemical, 2018, 265, 134-141. 2. Stensrud, K.F., Zanotti, K.J., Waggoner., A.S., Armitage., B.A., Photochemistry and photobiology, 2019, 95, 406-410. 3. Rajalakshmi, A. V., Palanisami, N., Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 117812.doi: 10.1016/j.saa.2019.117812 (In Press).

121

P30: Pincer-Nickel Catalysed N-Alkylation and Dehydrogenative Coupling Reactions

Vinay Arora,†a Moumita Dutta,†a Kanu Das,a Babulal Das,a Hemant Kumar Srivastava,*a Akshai Kumar *a,b

aDepartment of Chemistry, Indian Institute of Technology Guwahati, Guwahati – 781039, Assam, India. bCenter for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati –781039, Assam, India.

Nitrogen containing organic compounds are versatile intermediates that find immense synthetic value as precursors to pharmaceuticals, agrochemicals, dyes and fine chemicals.1 Recent years have witnessed a surge in the studies on direct N-Alkylation of amines using alcohols as the alkylating agents. This is mainly attributed to its environmental friendly approach where water is the sole by- product.2 However, these studies have been mainly limited to 4d and 5d transition metals.3 Herein, we report catalytic N-alkylation using Ni(II) NNN pincer complex with very high turnover (ca.34000 TONs).4 The reaction has been probed experimentally and theoretically to obtain a clear mechanistic understanding. The studies have been extended to dehydrogenative coupling that results in formation of benziimidazoles with high turnover (ca.2000 TONs).

References:

1. Lawrence, S. A., Amines: synthesis, properties and applications. Cambridge University Press: 2004. 2. Dobereiner, G. E.; Crabtree, R. H., Dehydrogenation as a Substrate-Activating Strategy in Homogeneous Transition-Metal Catalysis. Chemical Reviews 2010, 110 (2), 681. 3. Maji, M.; Chakrabarti, K.; Paul, B.; Roy, B. C.; Kundu, S. Adv. Synth. Catal. 2018, 360 (4), 722. 4. Arora.V.; Dutta, M.; Das, K.; Das, B.; Srivastava. K. H.,Kumar, A, Manuscript submitted.

122

P31: Palladium-catalyzed triflic acid-promoted regioselective hydroarylation of propiolic acid with aryl boronic acids: An expedient access to α-aryl acrylic acids

Sayyad Basha Kolimi, Rengarajan Balamurugan*

School of Chemistry, University of Hyderabad, Hyderabad-500046, India.

Transition-metal (TM)-catalyzed hydroarylation reactions of alkynes have received much attention, because they enable the net conversion of alkyne C≡C triple bonds into synthetically useful C=C double bonds in a highly regio- and stereoselective manner1 In this line, a novel palladium-catalyzed method has been developed for the synthesis of α-aryl acrylic acids from propiolic acid and aryl boronic acids (Scheme 1). The α-aryl acrylic acids and their derivatives are important structural moieties that widely exist in biologically active natural products and medicines. They also serve as key precursors for a series of non-steroidal anti-inflammatory drugs (NSAIDs), such as naprosyn, pirprofen, and fenoprofen.2

Scheme 1. Triflic acid-promoted palladium catalyzed regioselective hydroarylation of propiolic acid with aryl boronic acids.

References:

1. (a) Hayashi, T.; Inoue, K.; Taniguchi, N.; Ogasawara, M. J. Am. Chem. Soc. 2001, 123, 9918. (b) Nevado, C.; Echavarren, A. M. Synthesis 2005, 2, 167. (c) Hanna, L. E.; Konev, M. O.; Jarvo, E. R. Eur. J. Org. Chem. 2019, 184. (d) Manikandan, R.; Jeganmohan, M. Org. Biomol. Chem. 2015, 13, 10420. (e) Song, S.; Yu, J. T.; Jiang. Y.; Jiang, C. J. Org. Chem. 2015, 80, 2855. (f) Fu, M. C.; Rui, S.; Cheng, W. M.; Fu, Y. ACS catal. 2016, 6, 2501. 2. (a) Windsor, M. A.; Hermanson, D. J.; Kingsley, P. J.; Xu, S.; Crews, B. C.; Ho, W.; Keenan, C. M.; Banerjee, S.; Sharkey, K. A.; Marnett, L. J. ACS Med. Chem. Lett. 2012, 3, 759. (b) Zhu, S.F.; Yu Y.B.; Li, S.; Wang, L.X.; Zhou, Q.L. Angew. Chem. Int. Ed. 2012, 51, 8872.

123

P32: Microbiologial and Spectral Studies of Anil and Benzimidazolium Fluorochromate

A. Samidurai K. Anbarasu*

Department of Chemistry, Arignar Anna Govt. Arts College, Musiri – 621 211.

The aromatic and heterocyclic ring systems are playing a very important role in pharmaceutical drug synthesis. The present study was aimed to synthesis and evaluates the pharmacological latent of heterocyclic compound such as chromium (VI) compound. Microbiological potential of the prepared compounds anil and benzimidazolium fluorochromate were evaluated by disc diffusion method. Based on the results, the prepared compounds anil and benzimidazolium fluorochromate were significant potential against the selected organisms. The spectral characterization also revealed that the prepared compounds have aromatic and heterocyclic ring system.

References:

1. Sivamurugan, V., Rajkumar, G.A., Arabindoo, B., Murugesan, V. Indian Journal of Chemistry (B), vol. 44(1), pp. 144-147, (2015). 2. Bounar Rabah, Takia Lograda, Messaoud Ramdani Pierre Chalard a Gilles Feguiredo, Global Journal of Research Medicinal Plants & Indigenous Medicine, vol. 2, No. 2, pp. 73-78, 2013.

124

P33: An Unprecedented Blueshifted Naphthalimide AIEEgen for Ultrasensitive Detection of 4- Nitroaniline in Water via “Receptor-Free” IFE Mechanism

Mst Nasima Khatun,[a] Arvin Sain Tanwar,[a] Niranjan Meher,[a] Parameswar Krishnan Iyer*[a],[b]

aDepartment of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India bCentre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India

The development of a new naphthalene appended to a simple naphthalimide derivative (NMI) with aggregation-induced enhanced emission (AIEE) property for the sensitive detection of 4-nitroaniline (4-NA) in aqueous media is presented here. The newly designed naphthalimide AIEE gen has an exceptional blue-shifted condensed state emission, that is devoid of any receptor, yet accomplished ultrasensitive detection of 4-NA, one of the broad-spectrum pesticide that belong to the class III toxic chemical, at parts per billion level (LOD/36 ppb, Ksv = 4.1× 104 M−1) in water with excellent selectivity even in the presence of potentially competing aliphatic and aromatic amines. The reported probe is the first of its kind, demonstrating major advantages of receptor-free inner filter effect (IFE) mechanism for the sensitive detection of 4-NA using an AIEE genic probe. Excellent sensitivity for 4- NA is also achieved on paper-based test-strip for low-cost on-site detection.

References:

1. Khatun, M.N; Tanwar, A.S; Meher, N; Iyer, P.K. Chem. Asian J. 2019, 14, 4725.

125

P34: Rational control of hole injection and hole transport for high performance perovskite light emitting diodes.

Ramesh Babu Yathirajula1, M.Adil.Afroz2 , Ritesh Kant Gupta1, Parameswar.K.Iyer1,2,*

Centre for Nanotechnology1, and Department of Chemistry2 , Indian Institute of Technology Guwahati, Assam-781039.

Optoelectronic devices have been the most promising candidates in today‟s emerging technology. Since the milestone study of light-emitting diodes (LEDs), enormous efforts following the pioneering work have been focused on the improvement of devices in terms of their efficiency, stability and color tunability, making them ideal for the future display and ambient lighting. Therein, LEDs have drawn particular attention owing to their favorable merits of high efficiency, low cost, easy flexibility, large area, high resolution, and low energy consumption in the full-color display and solid-state lighting applications. We went for Nano Scale fabrication. Perovskite LEDs with a structure of FTO/NPD/PEROVSKITE Active layer/TPBi/LiF/Al . We achieved the brightness of 24,343 cd/m2 , EL Spectra at 533nm and CIE coordinates(0.22,0.74).The above device parameters for the champion device. Perovskite Solution made with (1.1:1) ratio of MABr and PbBr2. NPD acting as a Hole transporting layer & TPBi acting as a Electron transporting Layer. We compared different hole transporting layers like PVK, PEDOT: PSS and TCTA.

References:

1. B. Zhang, C. Qin, J. Ding, L. Chen, Z. Xie, Y. Cheng, and L. Wang, Adv. Funct. Mater. 20, 2951 (2010) 2. H. B. Wu, J. H. Zou, F. Liu, L. Wang, A. Mikhailovsky, G. C. Bazan, W. Yang, Y. Cao, Adv. Mater. 20, 696 (2008) 3. J. H. Zou, H. Wu, C. S. Lam, C. D. Wang, J. Zhu, C. M. Zhong, S. J. Hu, C. L. Ho, G. J. Zhou, H. B. Wu, W. C. H. Choy, J. B. Peng, Y. Cao, W. Y. Wong, Adv. Mater. 23, 2976 (2011) 4. B. H. Zhang, L. H. Liu, G. P. Tan, B. Yao, C. L. Ho, S. M. Wang, J. Q. Ding, Z. Y. Xie, W. Y. Wong, L. X. Wang, J. Mater. Chem. C, 1, 4933 (2013) 5. Z. Xiao, R. A. Kerner, L. Zhao, N. L. Tran, K. Lee1, and B. P. Rand, Nature Photonics, 11,108 (2017)

126

P35: Enhancing the Power Conversion Efficiency of organic solar cell by Incorporating Cost Effective 2,5-Difluorobenzene Units into the Polymer Backbone via Random Copolymerization

Maimur Hossain1; Parameswar K Iyer1,2*

1Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India 2Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India

Two new random terpolymers m1PTB7-Th and m2PTB7-Th have been designed and synthesized by incorporating a significantly low cost 2,5-Difluorobenzene in donor polymer for the application in organic photovoltaics (OPVs). Replacing 5 and 10 mol% of extremely expensive 3-fluorothieno[3,4- b]thiophene-2-carboxylate monomer in the well-known PTB7-Th by a > 100-times lower cost 2,5-

Difluorobenzene the new terpolymers m1PTB7-Th and m2PTB7-Th shows deeper HOMO energy level and comparable LUMO energy level because of this, there is a significant increase in Voc which helps to achieve higher power conversion efficiency (PCE) of 8.78% (Voc=0.850 V ) with m1PTB7-Th compare to 7.90% for PTB7-Th (Voc=0.780 V) and the 4.0% (Voc= 0.890 V) for m2PTB7-Th in bulk heterojunction photovoltaic device with the structure of ITO/PEDOT:PSS/Donor:PC71BM (1:1.5, w/w)/Ca/Al by using 3% of 1,8-diiodooctane (DIO) as solvent additive in the active layer.1 By using this low cost monomer incorporation in random copolymerization high performance polymer with improved Voc can be achieved.

Reference:

1. J. Gao, W. Wang, S. Zhang, S. Xiao, C. Zhan, M. Yang, X. Lu and W. You, J. Mater. Chem. A, 2018, 6, 179

127

P36: Suppression of Aggregation Caused Quenching in Pyrene by Introducing Different Rotor Groups: Photo-physical Studies and Hydrazine Sensing

1 1,2 Laxmi Raman Adil and Parameswar K. Iyer* .

1Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India 2Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India

Luminescent compounds have attracted considerable attention since the discovery of the ﬂuorescence (1565) by Nicolás Monardes.1 Although fluorescent compound developed over centuries, however still it is considered a dynamic research area. Fluorescent materials have broad applications viz. metal ion sensing, biosensing, cell imaging, organic light-emitting diodes (OLED).2-3 Generally, all the traditional fluorescence materials have intense emission in dilute solution or less concentration but low or no emission in higher concentration due to robust intermolecular interactions. This behavior of fluorophore termed as aggregation-caused quenching (ACQ). In contrary to established ACQ, some new material aggregates have constructive effects in fluorescence this phenomenon is termed as aggregation-induced emission (AIE).4 Hydrazine extensively used as a chemical reagent for various synthesis experiments and in rocket fuel as well. Hydrazine is listed as a carcinogen agent and it is highly toxic that caused serious threats to human and marine life system. Hence detection of hydrazine has attracted immense attention. We designed and synthesized three pyrene based derivatives PP, PBA,PBM, PBT,PBBT and PBI . We studied their photo-physical properties and we performed selectively sensing of hydrazine in water system with higher sensitivity and selectivity.

Figure 1: Pictorial repre. of the formation of pyrene derivative aggregates in an aqueous medium..

References:

1. Valeur, B.; Berberan-Santos, M. N. J. Chem. Educ. 2011, 88, 731−738. 2. Gopikrishna, P.; Das, D.; Adil, L. R.; Iyer, P. K. J. Phys. Chem. C, 2017, 121, 18137−18143. 3. Tanwar, A, S.; Adil, L. R.; Afroz, M. A.; Iye, P. K. ACS Sens. 2018, 3, 1451−1461. 4. Adil, L. R.; Gopikrishna, P.; Iyer, P. K. ACS Appl. Mater. Interfaces, 2018, 10, 27260−27268.

128

P37: Low-cost Mixed Halide Perovskite Thin Film Transistor: Role of Active Layer Morphology and Leakage Current through Dielectric

Anwesha Choudhury1, Parameswar Krishnan Iyer1,2*

1Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India 2Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India

Organic-inorganic perovskite has gained popularity in recent times because of its high carrier mobility[1], easy and low cost processing for various as active material for Field Effect Transistor(FET). Selection of the Gate Insulator (Dielectric) plays an important role in controlling the leakage current through gate insulator of FETs. In this paper we have demonstrated the variation of the growth and nucleation of perovskite thin film on various dielectric layers. Thereafter we report the fabrication and characterization of perovskite FET. We propose that growth of the perovskite depends on the dielectric layer on which it is coated. MACl and PbI2 based perovskite forms a stable film and the nucleation depends on the aging of the precursor solution. Hence by controlling of the perovskite film morphology, a high performing device can be obtained. Hence a low cost and well performing TFT is reported.

Cu Cu Source Drain

Perovskite Active Layer

Polymer Dielectric Layer PMMA 1%(Dielectric 3) Polymer Dielectric Layer PVA_3% (Dielectric 2)

Anodised Al2O3 (Dielectric 1) Aluminium Gate Contact Glass Substrate

Figure1: Perovskite TFT structure. (Schematic view of the transistor with Cu source drain)

129

P38: Effective Catalytic Activity of Mononuclear Copper(II) Complexes: Dimeric Association and Positive Redox Potential Pave the Way to Analogous the Function of Copper Oxidases

Balakrishnan Sasikrishnan, Mariappan Murali*

Coordination and Bioinorganic Chemistry Research Laboratory, Department of Chemistry, National College (Autonomous), Tiruchirappalli 620 001 Tamil Nadu

Copper containing metalloenzymes are very efficient natural catalysts involved in a great variety of reactions. In particular, ascorbate oxidase (AO) catalyzes ascorbic acid to dehydroascorbate. It belongs to the functional trinuclear copper cluster and the type-2 active site of copper(II) consists of two histidine molecules and a water molecule. Amine oxidase (AmO) is one of the type-2 copper oxidases occurs as homodimers and the geometry of the copper(II) active site is square pyramidal surrounded by three imidazole and two water molecules, which form a N3O2 chromophore with two labile O-donor sites. AmO catalyzes amine to aldehyde in a reaction RCH2NH2  RCHO + NH3, which is an important deamination reaction, involves two electron enzymatic processes. A type-3 copper enzyme, such as catechol oxidase (CO) consists of mainly dinuclear copper, each coordinated by three imidazoles from the histidine residues and the dicopper center is bridged by the oxy form of -2:2 peroxo moiety in its active site. It oxidizes catechol to o-quinone in the presence of dioxygen. Though numerous dinuclear copper(II) complexes successfully mimic the enzyme, both structurally and functionally, a great number of mononuclear copper(II) complexes too are known to show copper oxidase activity. The mixed ligand mononuclear copper(II) complexes of the type [Cu(L1)(L2)] where L1 and L2 together give a square-pyramidal (4+1) coordination geometry with labile binding site(s) are important to investigate their oxygen transfer process with ascorbic acid and benzylamine oxidation. However, a non-planar geometry around copper(II) is necessary for mononuclear complexes to be active for catechol oxidation. Thus, we have synthesized two green coloured mononuclear copper(II) complexes of the type [Cu(L1/L2)(phen)](ClO4) where the Schiff base is obtained from the condensation of salycilaldehyde and N,N-dimethylethylenediamine (HL1) (1) or 2-(2- aminoethyl)pyridine H(L2) (2) and phen is 1,10-phenanthroline. Single crystal X-ray analysis of 1 and 2 exhibits the distorted square pyramidal geometry and shows self-assembled dimeric association. They exhibit d-d and charge transfer transitions and reversible and positive CuII/CuI redox couple. Frozen DMF solution spectra show hyperfine structure while MeOH and MeCN display broad isotropic resonance, which indicates the presence of dimeric association in solution. The complexes are catalytically more effective in the oxidation of ascorbic acid to dehydroascorbic acid (100:1), amine to -1 aldehyde (100%) and 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone (Kcat; 1, 2148; 2, 1722 h ) using dioxygen, which models the functional activity of copper oxidases. References:

1. Sathya, V.; Murali, M. Inorg. Chem. Commun., 2018, 92, 55.

2. Sathya, V.; Murali, M. Inorg. Chim. Acta, 2019, 496, 1190.

130

P39: Selective Cytotoxic Activities of Ruthenium(II) Complexes on MCF-7 and HeLa Cancer Cell Lines

Balasubramaniam Selvakumaran, Mariappan Murali*

Coordination and Bioinorganic Chemistry Research Laboratory, Department of Chemistry, National College (Autonomous), Tiruchirappalli 620 001 Tamil Nadu

Although cisplatin has an excellent results in the treatment of some types of cancer, its efficacy is limited due to high toxicity and treatment resistance development. In this context is necessary the development of new and more effective anti-cancer agents, such as complexes based on ruthenium, which represent a more effective and less toxic alternative for treatment. Some theories suggest that ruthenium complexes are more specific and less toxic due to the advantages that represent their various oxidation states, as well as their resemblance to elements such as iron, and the union to biomolecules of transport as transferrin. The selectivity of drugs is very important in cancer treatment because if this is low the consequences of treatment are reflected in serious side effects because they affect both tumor cells and non-tumor cells. Therefore, novel ruthenium(II) complexes of the type

[Ru(bpy)2(en(1)/dmen(2)/deen(3))](PF6)2 (bpy, 2,2‟-bipyridine; en, ethylenediamine; dmen, N,N- dimethylethylenediamine; deen, N,N-diethylethylenediamine) were synthesized. In 1 and 2, two bpy (1 and 2) and en (1) or dmen (2) engaged in bidentate coordination to Ru(II) center, in the expected distorted octahedral fashion. The 1H NMR spectral studies on the complexes throw light on the nature of metal-ligand bonding and the conformations of the chelate rings. The electronic and emission spectral and electrochemical characterization has been accomplished. All the complexes have been explored for anticancer activity to MCF-7 and HeLa cells. Notably, complexes 2 (MCF-7: IC50, 28; SI,

> 8.7 and HeLa: IC50, 36; SI, > 6.8) and 3 (MCF-7: IC50, 42; SI, > 5.9 and HeLa: IC50, 31; SI, > 8.0) exhibit selective cytotoxicity to both the cancer cells while 1 (MCF-7: IC50, 209; SI, > 1.2 and HeLa:

IC50, 192; SI, > 1.3) is highly inactive. The complexes 2 and 3 were non-toxic to MDBK (normal cells) signifying target-specific nature of antitumor activity. Increased ROS concentration, as probed by DCFDA assay for complex 2, in the MCF-7 cancer cells was responsible for apoptotic cell death. Interestingly, complex 2 induces severe intracellular organelles such as cell membrane, actin cytoskeletal and mitochondria. FACS analysis showed G1 phase cell-cycle arrest in MCF-7 cells when treated with complex 2. The results of 2 and 3 displayed evidence of higher antiproliferative activity in tumor cells with an important index of selectivity when compare with normal cells. Hence, these two ruthenium(II) complexes would be a potential agent for the treatment of breast and cervical cancers. References

1. Pieter, B. C. A.; Sadler, P. J. Curr. Opin. Chem. Biol., 2008, 12, 197-206. 2. Allardyce, C. S.; Dyson, P. J. Platinum Metals Rev., 2001, 45, 62-69 3. Badisa, R. B.; Darling-Reed, S. F.; Joseph, P.; Cooperwood, J. S.; Latinwo, L. M.; Goodman, C. B. Anticancer Res., 2009, 29, 2993-2996.

131

P40: ε-Lactones and ε-Lactams via [4+3]-Annulation and 3,4-Dihydrocyclopenta[b]indoles via Decarboxylative Cyclization Using Indole Carboxylic Acids/Amides and Propargyl Alcohols

Shubham Debnath, Karuppu Selvaraj, K. C. Kumara Swamy*

aSchool of Chemistry, University of Hyderabad, Hyderabad-500046, Telangana, India

Indole fused five or seven membered rings (cyclopentene or ε-lactone and ε-lactam) are often found as structural motifs in many natural products and synthetic drugs.1 In recent years, there is a growing interest in the biological activities of ε-lactams/ε-lactones. The 3,4-dihydrocyclopenta[b]indole skeleton, which can be considered as indeno[2,1-b]indole,2 is important because it has been mapped in a route to cyanobacterial alkaloid. On the other hand, decarboxylative cyclization has emerged as a powerful tool for the synthesis of acyclic/polycyclic, natural/un-natural compounds.3 In continuation of work on the chemistry of propargylic systems,4 we herein demonstrate one-pot, metal-free decarboxylative cyclization of indole 2- or 3-carboxylic acids with propargyl alcohols for the synthesis of highly substituted ε-lactones, ε-lactams and 3,4-dihydrocyclopenta[b]indoles. The interesting part of this work is that unexpected carboxamide migration took place to the indole-2-position during the reaction of indole-3-carboxamide and propargyl alcohols.

References:

1. Selvaraj, K.; Debnath, S.; Kumara Swamy, K. C. Org. Lett. 2019, 21, 5447. 2. Zhang, L.; Zhu, Y.; Yin, G.; Lu, P.; Wang, Y. J. Org. Chem. 2012, 77, 9510. 3. Weaver, J. D.; Recio, A.; Grenning, A. J.; Tunge, J. A. Chem. Re ,2011, 111, 1846. 4. Selvaraj, K.; Kumara Swamy, K. C. J. Org. Chem. 2018, 83, 15043.

132

P41: Regioselective Synthesis of Pyrrolopyridine Derivatives under Mild Conditions

Manisha Choyal, Akanksha Agarwal and Neelima Gupta*

Centre of Advanced Study, Department of Chemistry, University of Rajasthan, Jaipur-302004, India

Pyrrolopyridine nucleus is constituent of many important naturally occurring bioactive alkaloids. Efforts have been made to synthesize pyrrolopyridines having variety of substitution patterns with potential importance in both synthetic and medicinal chemistry. 1,3-Dipolar cycloaddition reaction of pyridinium ylides is a widely applied method for the synthesis of Indolizine derivatives. Under present investigation, libraries of unsymmetrically substituted indolizine derivatives under milder conditions without using any oxidizing agent have been synthesized. Interesting observations pertaining to various compositions of regioisomers have been made. Auto-aromatisation of the cycloadduct under milder conditions has been achieved. The reaction mechanism has been investigated by computational calculations at DFT (B3LYP/6-31+g**) level to examine observed regioselectivity using unsymmetrical dienophile. The experimental yield of the products is sufficient and spectroscopic techniques - 1H-NMR, 13C-NMR and HRMS have been used for characterization of products. Biomolecular interactions of selected representatives have been identified using Docking studies.

133

P42: Impact of stereo-electronic properties of a molecule on CEST efficiency

Subhayan Chakraborty and Arindam Ghosh*

School of Chemical Sciences, National Institute of Science Education and research, Bhubaneswar

Chemical exchange saturation transfer (CEST) NMR is widely used for a number of applications including identification of low population states in proteins1 and study of ligand-binding2. Very recently CEST has found a new application in the form of proton density tuning for MRI imaging. CEST contrast agents are exogenous or endogenous compounds that contain exchangeable protons, which are selectively saturated and after transfer of this saturation to solvent water, the depletion of the water signal intensity is used for contrast during the imaging process. Over the past few decades this new generation of contrast agents has evolved as a good competitor of the widely used Gd (III) contrast reagents. CEST contrast agents are broadly divided in two categories, Dia-CEST (without metal ion) 3 agents and para-CEST (with metal ion) 4 agents. In either category, to achieve a good CEST contrast tuning the stereo-electronic properties and plausibility of intramolecular hydrogen bond within the molecule becomes extremely important, as it governs the chemical environment of the exchangeable moiety which in turn influences the MTR asymmetry. Moreover, in case of para-CEST contrast agents, the type of free base used for forming the metal complex as well as the induced magnetic properties at the metal center in solution plays important role in making an effective CEST based contrast agent. Apart from the chemical properties of the reagent, determining and calibrating saturation pulse parameters like pulse-power, pulse-shape, saturation duration, saturation offset, recycle delay are also important as mistune of any one of these can potentially have dramatic effect on the success of the experiment even with a very fine contrast agent. In this presentation we demonstrate the effect of these important parameters on the CEST contrast capability of few recently proposed4 and widely known CEST contrast agents.

References:

1. Vallurupalli et al. Journal of American chemical society, 2012, 134, 19, 8148 2. Binbay et al. Universal journal of public health 5(6) 320, 2017 3. Sangeeta ray Banerjee et al. Chemistry A European journal, 2018, 24, 7235 4. Rabindra N. Pradhan, Subhayan Chakraborty, Pratibha Bharti, Janesh Kumar, Arindam Ghosh,* and Akhilesh K. Singh* Dalton trans, 2019,48, 8899.

134

PP43: Synthesis, Reactivity and Emission Properties of Copper, Zinc and Cadmium Formylbenzoate Complexes

Jitendra Nath, Arup Tarai, Jubaraj B. Baruah*.

Chemistry Department.Indian Institute of Technology, Guwahati 781039, India.

To probe the changes in aggregation induced emission and chemo-sensitivity of low-nuclearity metal complexes caused by different pollutants on 1,10-phenanthroline containing formylbenzoate complexes of zinc, copper and cadmium, several low nuclearity complexes were synthesized and characterized. These complexes were designed so as to understand the possible effect of emission through a pull-push mechanism as illustrated in figure 1a or by chemical reactivity of the aldhehyde group on the ligand. The d10- zinc and cadmium complexes were weakly fluorescent and their emissions changed upon interactions nitro-anilines to use them for sensing purposes. The quenching caused by 4-nitroaniline by the zinc complex is shown in the Figure 1b. The photo-luminescence was studied by study on the photo-luminescence decay profiles and also by dynamic light scattering experiments. We also explored the reactivities of copper(II) formylbenzoate complexes towards hydroxyl-amine and established structure of an unusual complex formed by C-H activation of aldehyde and also have characterised an inclusion complex of bis(1,10- phenanthroline)(chloro)copper(II)chloride encapsulating ((hydroxyimino)methyl) benzoic acid in the hydrogen-bonded chloride-hydrate assembly formed by self-assembling. The presentation will include the synthetic, characterisation of those complexes and elucidation of the emission properties of those complexes.

(a) (b) Fig. 1: (a) Electronic push−pull effect in a portion of a metal complex. (b) Fluorescence quenching of bis-phenanthroline zinc formylbenzoate complex by different amounts of 4-nitroaniline

Reference:

1. Nath, J.; Tarai, A.; Baruah, J. B. ACS Omega 2019, 4, 18444 −18455.

135

PP44: Visible-Light-Induced Oxidative Cleavage of C-C Triple Bond via Hydroamination: Direct Synthesis of Oxamates from Amines and Activated Alkynes

Narenderreddy Katta, and Duddu S. Sharada*

Department of Chemistry.Indian Institute of Technology- Hyderabad

The direct oxidative cleavage of activated alkynes via hydroamination has been described using organic photocatalyst under visible-light irradiation at room temperature. In this reaction, the single electron oxidation of an in situ formed enamines undergo radical coupling with oxidant which finally delivers the oxamates. The key features of this photocatalytic reaction are the mild reaction conditions, metal-free organic dye as a photocatalyst, TBHP plays a dual role as “O” source and for the regeneration of photocatalyst.

References:

1. Katta, N.; Ojha, M.; Murugan, A.; Sagar, A.; Sharada, D. S 10.26434/chemrxiv.7322402 2. Sagar, A.; Katta, N.; Ajoy, C.; Sharada, D. S Eur. J. Org. Chem. 2019, 7, 1542. 3. Babu, V.N.; Murugan, A.; Katta, N.; Sharada, D. S. J. Org. Chem. 2019, 84,6631. 4. Murugan, A.; Babu, V.N.; Sabari, N.; Sharada, D. S. J. Org. Chem. 2019, 84,7796.

136

P45: Use of Dimeric Excited States of the Donors in D4-A Systems for Accessing White light Emission, Persistent Room Temperature Phosphorescence and Invisible Security Ink

Harsh Bhatia, Debdas Ray*

Department of Chemistry, Shiv Nadar University

Pure organic white light emitters with persistent room temperature phosphorescence (RTP) feature have unique advantages and various potential applications. However, the studies of single- component organic white light emitters with persistent RTP and visible light excitation (VLE)- dependent efficient RTP features remain a challenging area of research in photophysics. Herein, we synthesized three terephthalonitriles derivatives in which 2,3,5,6-positions are covalently attached to 2-ﬂuoro-phenoxy (TOF), 2-chloro-phenoxy (TOC), and 2-methoxy-phenoxy groups (TOM)1 to give twisted geometries. We observed that powder samples of both TOC and TOM show white light emission with CIE coordinates of (0.32, 0.38) and (0.26, 0.33), respectively, while TOM gives VLE- dependent efficient RTP under ambient conditions. In addition, both TOC and TOF exhibit a dim afterglow feature. Spectroscopic studies reveal that emission of these chromophores originates via radiative decay of monomeric excited states (singlet, triplet), dimer-like excited states (DLES) (singlet, triplet), and aggregated triplet states. Detailed spectroscopic and X-ray analyses reveal the signature of DLES that is formed via conformational reorganization of the phenoxy donors in the excited states. Single-crystal X-ray diffraction analysis shows that the multiple lp(O)···π(C≡N)/C≡C, Cl/F···π, and hydrogen-bonding interactions in the X-ray structures play a signiﬁcant role in facilitating intersystem crossing2, stabilizing multiple triplet states, and suppressing non-radiative decay, thereby triggering dim afterglow under ambient conditions. We found that TOC and TOF exhibit persistent RTP with lifetimes of 139 and 736 ms, respectively, when embedded in polyvinyl alcohol matrix. Given the persistent RTP feature, invisible security ink application is developed.

Figure: Fluorescence and Phosphorescence emission from a single molecule in powder form at room temperature using monomer, dimer and aggregates for white light emission.

References:

1. Bhatia, H.; Ray, D.; J. Phys. Chem. C 2019, 123, 22104-22113. 2. El-Syed, M. A.; J. Chem. Phys. 1963, 38, 2834-2838.

137

P46: Optical Detection and Separation of Heavy Metal Ions Using Chitosan based Hydrogels

Megha Sara Jacob, R Liju, E Rajkumar*

Department of Chemistry, Madras Christian College, Chennai, 600059

The continuous growing trend of industrialization and globalization has set heavy metals among the prominent sources that augment environmental pollution. The concern regarding the remediation of the natural ecosystem has drawn a great multitude of scientists towards the detection and separation of heavy metals. The present work is based on designing and synthesizing a polymeric hydrogel for the absorption and separation of heavy metals in solutions. Chitosan, the second most abundant biopolymer, was crosslinked via a suitable crosslinker to enhance its structural stability and properties. The obtained gels were characterized via IR spectroscopy and its surface morphology studied by using SEM technique. Hydrogels containing carbon dots exhibited enhanced absorption of heavy metals through complex formation. The absorbed metal ions gave rise to characteristic colours that can be observed through naked eye thereby providing qualitative results. The interesting results are discussed during the presentation.

Reference:

1. Neelam Gogoi.; Mayuri Barooah.; Gitanjali Majumdar.; Devasish Chowdhury. ACS Appl. Mater. Interfaces 2015, 7, 5, 3058-3067.

2. Matthew D. Cathell.; JanahC.Szewczyk.; Frances A. Bui.; Carrie A. Weber.; Jessica D .Wolever.; Jennifer Kang.; Caroline L. Schauer. Biomacromolecules 2008, 9, 289- 295.

138

P47: Tuning thiaza[5]helicenes for better optoelectronic properties - A DFT and TDDFT study

R.Lipin and Rajadurai Vijay Solomon*

Department of Chemistry, Madras Christian College, Chennai, 600059

For the past 100 years helicenes are found to be useful in many fields due to its fascinating chiral, physical, electronic and optical properties. Substituents in the bay area, also called the fjord region of helicenes are known to increase the enantiomerization barrier and torsion angle in the structure. A recent study shows that substituting at the bay region also influence the spectroscopic properties in addition to the solid state structure. In the present study, Thiaza[5]helicenes derivatives have been designed and screened for better optoelectronic properties using DFT and TDDFT calculations. The main focus of this work is to understand and analyse the structure-property relationship of these derivatives and to offer insights to design new Thiaza[5]helicene candidates for optoelectronic applications.

Figure: Structure of bay-substituted thiaza[5]helicene

References:

1. Marc Gingras. Chem. Soc. Rev., 2013, 42, 1051. 2. Ravat, P.; Hinkelmann, R.; Steinebrunner, D.; Prescimone, A.; Bodoky, I.; Jurí ek, M. Org. Lett. 2017, 19, 3707. 3. Mathias Daniels.; Flip de Jong.; Tom Vandermeeren.; Luc Van Meervelt.; Mark Van der Auweraer.; Wim Dehaen. J. Org. Chem. 2019, 84, 21, 13528. 4. R. Vijay Solomon.; P. Veerapandian.; S. Angeline Vedha.; P. Venuvanalingam. J. Phys. Chem. A 2012, 116, 4667.

139

P48: Enzyme mimicking activity of triggered MCM-41 incorporating Co(II) Schiff base complex

Manikandan Palaniappan, Selvi Arumugam, Rubiga Muthusami, Rajavel Rangappan*

Department of chemistry, Periyar University, Salem-11 (

Co(II)–Schiff base complex was achieved by the condensation of acenaphthylene-1,2-dione, S- methylbenzyldithiocarbazate and 3-aminopropyl triethoxy Silane (3-APTES) with cobalt acetate. The mesoporous material MCM-41 was incorporated using synthesized Co(II)–Schiff base complex for enzyme catalytic efficiency. The catalyst was characterized by various techniques such as elemental analysis, SEM, TEM, LA-XRD, FTIR, N2 adsorption–desorption, TG-DTA, solid state UV–vis and XPS. LA-XRD and adsorption–desorption analysis confirms incorporation of Co(II)–Schiff base complex with MCM-41. In another hand, the result of spectral studies exposed the mesoporous material comprising the complex inside. Co(II) Schiff base complex functionalized on MCM-41 was utilized as an efficient redox catalyst for 2-aminophenol synthase.

Figure: 1 Proposed structure of 2-aminophenol redox reaction mesoporous supported Co(II) Schiff base complex .

References:

1. C.Favero.;M.B.Closs.;G.B.Galland.;R.Stieler.;E.Rossetto.; K. Bernardo-Gusmão. Journal of Catalysis 2019, 377, 63. 2. Rubiga.M.; Malathy.M.; K. Irena.; Anbarasu G.; Chozhanathmisra.M and Rajavel.R.. New J. Chem., 2018, 42,18608.

140

P49: Turn-On Terbium Luminescence Method for Formaldehyde and Hydrogen Peroxide Sensing

Arnab Dutta, Dipankar Bhowmik and Uday Maitra*

Department of Organic Chemistry, Indian Institute of Science, Bengaluru

Formaldehyde (HCHO) and hydrogen peroxide (H2O2) are two biologically relevant small molecules that are, endogenously, generated and maintained at an optimum concentration via several biological processes. Excessive concentration of HCHO and H2O2 are implicated in various diseases such as cancer, asthma and neurodegenerative diseases.1,2 Therefore, efficient detection of these molecules is extremely important. Lanthanides (Ln3+) are well known for their sharp line like emission and long excited state lifetime. However, their luminescence intensity is weak which can be attributed to the lower value of molar extinction coefficient. From our group it has been shown that luminescence intensity of Ln3+ can be increased substantially by doping a sensitizer molecule in the lanthanide cholate (LnCh) hydrogel.3 Recently we have found that some functionalized aromatic compounds (Ar- FG2 and Ar-FG4) sensitize terbium (Tb3+) in TbCh hydrogel. We have developed a “turn-on” luminescence method using this system to detect HCHO and H2O2. In this method, we strategically modified the sensitizer molecules to make pro-sensitizers, Ar-FG1 and ArFG3, which do not sensitize 3+ Tb (Scheme 1). Upon reaction with the analytes, HCHO and H2O2, they produce Ar-FG2 and Ar- FG4, respectively, resulting in a “turn-on” luminescence response. This method is found to be very selective and sensitive, enables detection of analyte in nanomolar range. The detection method was further simplified by using a low-cost, user-friendly paper-based approach.

3+ Scheme 1: Scheme of representation for the detection of HCHO and H2O2 using Tb luminescence as the output signal.

References:

1. Swenberg, J. A.; Moeller, B. C.; Lu, K.; Rager, J. E.; Fry, R.; Starr, T. B. Toxicol Pathol., 2013, 41, 181. 2. Lisanti, M. P.; Martinez-Outschoorn, U. E.; Lin, Z.; Pavlides, S.; Whitaker-Menezes, D.; Pestell, R. G.; Howell, A.; Sotgia, F. Cell Cycle, 2011, 10, 2440. 3. Bhowmik, S.; Banerjee, S.; Maitra, U. Chem. Commun., 2010, 46, 8642.

141

P50: Conformation dependent selectivity of calix[4]crown-6 ether toward metal ions

Loveleen Kaur Gulati, Gurleen Kaur Gulati, Arvind Kumar, Arun Kumar and Satish Kumar*

Department of Chemistry, St. Stephen’s College, University Enclave, Delhi-110007.

Last couple of decades have seen an increased interest in the ionophoric properties of calix[4]arenes. 1 The calix[4]arene architectures are known to exist in four different conformers called cone, 1,2- alternate, 1,3-alternate and partial cone.1 The change in conformer causes a change in the cavity size, which in turn produces a binding preference for a particular cationic species. A reaction between two 1,3-alternate OH groups and polyether moiety produces a new ionophore known as calix[4]crown ether, with better selectivity and limits the number of conformers of calix[4]arene architecture to three (cone, 1,3-alternate and partial cone). 2 Calix[4]crown-6 ethers possess superior ionophoric properties compared to crown ether and calix[4]arene.2 However, selectivity is still dependent on the conformers of calix[4]arene skeleton.3, 4 Hence, it is important to investigate the conformational dependence of ionophoric properties of calix[4]crown-6 ether. The computational methods can be an important tool to understand and investigate the conformational properties of calix[4]crown ether along with its complex with metal ions. Therefore, calix[4]crown-6 ether was chosen for this study and MPW1PW91 functional was used to investigate the conformations of the ether and its complex with metal ions. The study revealed the factors affecting the stability of different conformers of calix[4]crown-6 ether along with their selectivity towards different metal ions. H-bonds were found to play a crucial role in the determination of stability of different conformers, while the crown ether ring size of the conformer seemed to influence the selectivity towards a particular metal ion.

References:

1. Chawla, H. M.; Pant, N.; Kumar, S.; Kumar, N.; Black David St, C., Calixarene-based materials for chemical sensors. In Chemical Sensors Fundamentals of Sensing Materials, Korochenkov, G. S., Ed. Momentum Press New York: 2010; Vol. 3, p 300. 2. Chawla, H. M.; Hundal, G.; Kumar, S.; Singh, P., J. Incl. Phenom. Macrocycl. Chem. 2012, 72 (3), 323-330. 3. Chawla, H. M.; Sahu, S. N.; Shrivastava, R.; Kumar, S., Tetrahedron Lett. 2012, 53 (17), 2244-2247. 4. Greene, A. F.; Breland, D. K.; Kumar, S.; Fujiwara, T.; Webster, C. E., Abstracts of Papers, 239th ACS National Meeting, San Francisco, CA, United States, March 21-25, 2010 2010, INOR-227.

142

P51: Synthesis and evaluation of Spiropyran-polymer conjugate

Gurleen Kaur Gulati, Loveleen Kaur Gulati, Arvind Kumar, Sojkumar dominic and Satish Kumar*

Department of Chemistry, St. Stephen’s College, University Enclave, Delhi-110007.

Last several decades have seen an intensive effort towards the development of light responsive polymeric materials for application as sensors (for pH, temperature, ionic species), drug delivery vehicles, photochromic lenses and storage devices.1, 2 The application of spiropyran derivatives in such materials improves fatigue resistance, reversibility and reusability.2 Spiropyran represents a family of photochromic molecules, which display excellent colorability and light responsive behavior along with excellent fatigue resistance. Spiropyran derivatives are known to display two interconvertible isomeric forms. One isomeric form of the spiropyran is colorless and nonpolar (spiro), while the other form is polar and colored (merocyanine or MC). The two forms can be converted reversibly to each other through application of light, heat or change in temperature. In addition, aggregates of merocyanine form have also been reported to be induced by ionic species, which lead to a change in color of fluorescence. The properties of spiropyran derivatives can be exploited further through conjugation with biodegradable polymers to yield photo-switchable polymeric systems with interesting properties, e.g., reversible nanomaterials.3, 4 Therefore, a substituted spiropyran molecule was conjugated with a poly(L-lactide) through ring opening polymerization. The polarity difference between the SP and MC forms was used to disrupt or produce aggregated structures. Owing to its non-planarity, the SP form supports disruption of aggregated structure, while planar merocyanine form supports the formation of aggregated structures. The photo-responsive polymers can thus be used for the recognition of ionic species, which may be released through application of light. The results of synthesis and properties of the product will be discussed.

References:

1. Mutoh, K.; Kobayashi, Y.; Abe, J., Dyes Pigm. 2017, 137, 307. 2. Sahoo, P. R.; Prakash, K.; Kumar, S., Coord. Chem. Rev. 2018, 357, 18. 3. McConnell, A. J.; Wood, C. S.; Neelakandan, P. P.; Nitschke, J. R., Chem. Rev. 2015, 115 (15), 7729. 4. Hu, J.; Zhang, G.; Ge, Z.; Liu, S., Prog. Polym. Sci. 2014, 39 (6), 1096.

143

P52: A portable and sensitive photochromic probe for Mercuric ions in water

Arvind Kumar, Ishana Kathuria, Sojkumar Dominic, Arun Kumar, and Satish Kumar*

Department of Chemistry, St. Stephen’s College, University Enclave, Delhi-110007.

The release of toxic metal ion in our environment is leading to contamination of water bodies, which are extensively utilized by the human population to sustain lives.1, 2 Mercuric ion is among the most toxic metal ion pollutant that affects the health of the human population and aquatic life.3 The accumulation of mercuric ion in the marine life further aggravate the toxicity problem due to the formation of methylmercury.4 The exposure to excessive concentration of mercuric ion leads to disease such as Minamata disease.1 Therefore, there is a need to monitor the concentration of mercuric ion in water. In this context, a benzothiazolium salt was synthesized having two oxygen atoms ortho to each to bind toxic metal ions. The crystal structure of the dye displayed an extensive network of H-bond. The structure was established through 1H, 13C-NMR, HR-MS techniques. The probe detected the presence of mercuric ions in water by producing visible color change (pink to colorless). The mercuric ion dis-aggregated the H-bond network of the receptor through coordination with oxygen atoms present in the molecule. Test strips loaded with receptor were developed which could be used for field applications for mercuric ions monitoring in water. Density functional theory calculations were also performed to further investigate the mechanism of the complex formation, which indicated that one molecule of the probe binds one molecule of mercuric ion and supported Job‟s plot data. The TD-DFT studies further suggested the disappearance of color by indicating an increase in the HOMO-LUMO gap in the complex compared to the HOMO-LUMO gap in the benzothiazolium dye based probe.

References:

1. Spiegel, S. J., Lancet 2017, 390 (10091), 226-227. 2. Kumar, A.; Sahoo, P. R.; Arora, P.; Kumar, S., J. Photochem. Photobiol. A 2019, 384, 112061. 3. Sahoo, P. R.; Prakash, K.; Kumar, S., Coord. Chem. Rev. 2018, 357, 18-49. 4. Okpala, C. O. R.; Sardo, G.; Vitale, S.; Bono, G.; Arukwe, A., Crit. Rev. Food Sci. Nutr. 2018, 58 (12), 1986-2001.

144

P53: Homoleptic zinc-catalyzed hydroboration of aldehydes and ketones in presence of HBpin.

Gobbilla Sai Kumar, Adimulam Harinath, Rajrani Kawaria and Tarun K Panda*

Department of Chemistry, Indian Institute of Technology, Hyderabad Kandi-502285, Sangareddy, Telangana, India.

In recent decade, hydroboration of aldehyde or ketones in presence of catalyst has been keen interest for the synthesis of organic molecules.1 Boronate ester compounds are preferred over other organometallic reagents owing to their nontoxicity and stability.2 Hence, a wide range of metal catalysts have been used in the hydroboration of various unsaturated moieties, including alkenes, alkynes, imines, nitriles, and carbonyl compounds.3,4 Here, we report the reaction between N-phenyl- O-phenyl-enediamine and pyrrole-2-carboxyaldehyde to afford the N-phenyl-O-phenyl- enediiminepyrolyl ligand {L-H2} in quantitative yield. A one-pot reaction between {L-H2} and diethylzinc (ZnEt2) in a 2:1 ratio afforded the homoleptic zinc metal complex [{L-H}2Zn] (1). The solid- state structures of ligand {L-H2} and zinc complex 1 were confirmed using X-ray crystallography. Further, complex 1 was used for chemoselective hydroboration of aldehydes and ketones in the presence of pinacolborane (HBpin) at ambient temperature to produce the corresponding boronate esters in high yield.

Figure 1: Schematic representation for hydroboration of aldehyde or ketones in presence of homoleptic zinc metal complex 1.

References:

1. Lennox, A. J.; Lloyd-Jones, G. C. Chem. Soc. Rev. 2014, 43, 412. 2. Carroll, A. -M.; O'Sullivan, T. P.; Guiry, P. J.; Adv. Synth. Catal. 2005, 347, 609. 3. (a) Wen, H.; Liu, G.; Huang, Z. Coord. Chem. Rev. 2019, 386, 138; b) Zhang, L.; Peng, D.; Leng, X.; Huang, Z. Angew. Chem. Int. Ed. 2013, 52, 3676. 4. a) Harinath, A.; Bhattacharjee, J.; Gorantla, K. R.; Mallik, B. S.; Panda, T. K. Eur. J. Org. Chem. 2018, 24, 3180.; b) Harinath, A.; Bhattacharjee, J.; Nayek, H. P.; Panda, T. K. Dalton trans. 2018, 47, 12613. c) Harinath, A.; Banerjee, I.; Bhattacharjee, J.; Panda, T. K. New J. Chem. 2019, 43, 10531.

145

P54: Efficient and Chemoselective Hydroboration of Organic Nitriles by TiIV Catalyst Supported by Unsymmetrical Acenaphthenequinonediimine Ligand

Indrani Banerjee, Srinivas Anga, Kulsum Bano, and Tarun K. Panda*

Department of Chemistry, Indian Institute of Technology, Hyderabad Kandi-502285, Sangareddy, Telangana, India.

Recent trends in synthetic chemistry demonstrate the growth in use of synthetic methods in multicomponent reactions and catalysis using earth-abundant metals. Titanium being the second- most abundant and non-toxic metal on earth has been used as a preeminent catalyst in widespread applications.1 In recent years, synthetic chemists find organoboron compounds advantageous as they are easy to handle and are atom efficient. Over the past few years, numerous methods have been reported on the hydroboration of nitriles using transition metals and alkaline metals.2 We recently reported a number of Ti(IV) amido complexes and found that these complexes indeed support various catalytic reactions under ambient conditions.3 Herein, we discussed the synthesis, characterization, and utilization of a titanium (IV) complex (1) supported by a monoanionic ligand as a pre-catalyst for the hydroboration of nitriles to afford diboryl amines.4 Complex 1 exhibited high conversion, superior selectivity, and broad functional group tolerance during hydroboration of nitriles with both HBpin and HBcat under mild conditions.

Figure 1. Ti(IV) catalysed hydroboration of organic nitriles.

References:

1. (a) Odom, A. L.; McDaniel, T. J. Acc. Chem. Res. 2015, 48, 2822. (b) Yun, J.; Buchwald, S. L. J. Am. Chem. Soc. 1999, 121, 5640. 2. (a) Kaithal, A.; Chatterjee, B.; Gunanathan, C. J. Org. Chem. 2016, 81, 11153. (b) Weetman, C.; Anker, M. D.; Arrowsmith, M.; Hill, M. S.; Kociok-Köhn, G.; Liptrota, D. J.; Mahon, M. F. Chem. Sci. 2016, 7, 628. 3. (a) Bhattacharjee, J.; Das, S.; Kottalanka, R. K.; Panda. T. K. Dalton Trans, 2016, 45, 17824. (b) Naktode, K.; Das, S.; Bhattacharjee, J.; Nayek, H. P.; Panda, T. K. Inorg. Chem. 2016, 55, 1142 4. Banerjee, I.; Anga, S.; Bano, K.; Panda. T. K. J. Organomet. Chem. 2019, 902, 120958.

146

P55: Ruthenium catalyzed N-alkylation of amines with alcohols via barrowing hydrogen methodology

Sekar Gayathri, Periasamy Viswanathamurthi

Department of Chemistry, Periyar University, Salem - 636011

The catalytic construction of C−N bonds via borrowing hydrogen methodology [1], have recently received much attention since nitrogen functionalities occur in various compounds of synthetic and pharmaceutical significance as well as in important biologically active molecules. In contrast with other transition-metal-catalyzed methodologies, e.g., amination of organohalides (Buchwald-Hartwig amination), reductive amination of carbonyl compounds, hydroamination and hydroaminomethylation of carbon-carbon unsaturated compounds, etc., the N-alkylation of amines with alcohols, produced water as the sole by-product, may serve as a relatively green and environmentally benign alternative. Moreover the use of alcohols as the alkylating agent is direct and simple as the alcohols are readily available, highly stable, low in toxicity, easily stored and handled, low in cost, and relatively high in atom efficiency. Several ruthenium complexes containing phosphine ligands have been employed in the N-alkylation of amines with alcohols in good yields and selectivity [2]. However, they are not trouble free as most of the methods reported have some difficulties like the requirement of high temperature, pressure and prolonged reaction times up to a few days. The drawbacks to the reported catalysts necessitate the synthesis of new catalysts. Hence, new ruthenium catalysts have been designed, synthesized and characterized by analytical and spectroscopic (IR, UV-Vis, 1H & 13C NMR, ESI-Mass and single crystal X-ray crystallography) techniques. The catalytic property of the new complexes was screened for N-alkylation of amines with alcohols under optimized conditions. The role of co-ligands in determining the catalytic activity for N-alkylation was also investigated.

References:

1. R. Ramachandran, G. Prakash, S. Selvamurugan, P. Viswanathamurthi, J. G. Malecki, V. Ramkumar. Dalton Trans. 43 (2014) 7889. 2. R. Ramachandran, G. Prakash, S. Selvamurugan, P. Viswanathamurthi, J. G. Malecki, W. Linert, A. Gusev, RSC Adv. 5 (2015) 11405.

147

P56: Microwave-Assisted the Suzuki-Miyaura Cross Coupling Reaction Using Ni-Complex Functionalized MCM-41 as an Efficient and Reusable Heterogeneous Catalyst

M. Bharathi, S. Indira, G. Vinoth and K. Shanmuga Bharathi*

Department of Chemistry, Periyar University, Salem - 636011

A new Ni-Schiff-Base Complex-bipy on MCM-41 was prepared. The prepared compound has been extensively characterized by FT-IR, UV-DRS, Small angle-XRD, SEM-EDX, BET, ICP-OES and TEM analysis. Suzuki-Miyaura cross-coupling reaction for the Synthesis of biaryl derivatives was carried out under microwave irradiation using Ni-Complex-bipy-MCM-41 as an efficient catalyst. Microwave energy was employed to obtain the desired products in excellent yields (~95 %). Notably, Catalyst was recovered by simple filtration method and reused up to four cycles without any significant loss in the yield. Moreover, the yields of the products are much increased while using Ni-MCM-41 complex as catalyst instead of using pure MCM-41 and Ni-Complex.

References:

1. Dhara, K; Sarkar, K; Srimani, D; Kumar Saha, S; Chattopadhyay, P; Bhaumik, A. Dalton Trans. 2010, 39, 6395. 2. Vinoth, G; Indira, S; Bharathi, M; Nandhakumar, A; Sathishkumar, K; Shanmuga Bharathi, K. J.Coord. Chem. 2019, 71, 3934.

148

P57: A bisphenol based fluorescence chemosensor for the sequential detection of Zn2+ and PPi ions and its bioluminescence imaging

Rajasekaran Dhivya, Perisamy Viswanathamurthi*

Department of Chemistry, Periyar University, Salem - 636011

The design and development of chemosensors have expanded substantially in last few decades. Synthesis of new chemosensors for detection of transition metals including heavy metal ions have been of great interest for chemists, in recent years as they play important roles in the areas of chemical, biological and environmental systems.1 Fluorescent sensor technology has attracted considerable attention as a type of facile and efficient detection method for sensing biological and chemical species because of their simplicity, versatility, high selectivity and sensitivity. Based on the above-mentioned premise, herein we report the synthesis of bisphenol based Schiff base chemosensor (L). The new fluorescent chemosensor (L) exhibits sequential detection of Zn2+ and pyrophosphate (PPi) anion in mixed buffer solution at physiological pH.2 The probe exhibits turn-on fluorescence response with the addition of Zn2+ ions even as low as 1 nM. Further, addition of pyrophosphate anion led to quenching of fluorescence activity of L-Zn2+ ensemble. In addition, the sensitive fluorescence probe (L) has been utilized as a powerful tracker for zinc and pyrophosphate ion in biological systems.

References:

1. Song, T; Cao, Y; Zhao. G; Pu, L. Inorg. Chem. 2017, 56, 4395. 2. Wang, J; Lin, W; Li, W Chem. Eur. J. 2012, 18, 13629.

149

P58: Single luminescent chemosensor for the discriminative detection of mercury ion in environment and its application on live cell imaging

Venkatachalam Kavitha, Periasamy Viswanathamurthi*

Department of Chemistry, Periyar University, Salem - 636011

Mercury (II) is one of the environmentally most important cations whose toxicity has long been recognized as a permeating environmental problem, because marine aquatic organisms convert inorganic mercury Hg2+ into neurotoxic methyl mercury which bioaccumulates to the human body and in other organisms through propagation in the food chain. This bioaccumulated mercury in living organisms leads to adverse impacts on nervous systems, brain, kidney and many cognitive diseases like minamata disease and alzheimer‟s disease to human body. Hence, selective recognition of such harmful metal ions at its submicromolar level for biological, environmental, ecological, and medicinal purposes is extremely beneficial as well as essential. Several conventional techniques such as electrochemical method, spectroscopy, chromatography etc ., have been used but all this methods are lacking from practical consequences.1 Therefore, the recent researches were focusing on chemical sensor technique to detect the mercury ion because of its advantages like sensitivity, selectivity, real time, rapid response, non-invasive and non-destructive properties.2 Based on all, in this work a novel bisphenol A based probe having fascinating spectral properties have been designed and synthesized for the selective detection of mercury ion in environment and biological systems even in nanomolar level concentration. The probe is also utilized to detect mercury ion in realistic samples.

References:

1. Chen, Y; Wang, X; Yang, X. F; Zhong, Y; Li, Z; Li, Z. Sens. Actuator B- Chem. 2015, 206, 268. 2. Cheng, C. C; Chen, Z. S; Wu, C. Y; Lin, C. C; Yang, C. R; Yen, Y. P. Sens. Actuators B- Chem. 2009, 142, 280.

150

P59: Synthesis, characterisation and antibacterial activity of 1,2,3 triazoles.

Anis Ahmed Sheikh1, Syed Ummul Khair Asema1, Shaukat Patel Karimkha2, Sayyad Sultan Kasim1*

1Department of Chemistry, Maulana Azad College of Arts, Science & Commerce, Aurangabad. 431001. MS. India. 2Adarsh Senior College, Omerga, 413606 District Osmanabad. MS. India.

1,2,3 triazoles are important nitrogen heterocyclic compounds having diverse biological applications in medicinal chemistry. In spite of their vital applications in medicinal field these compounds are also more advantageous in agriculture and organic synthesis. The simple synthesis of these compounds through “Click reaction” and good yield attracts the much attention of researchers towards these fruitful compounds. In this research work we have synthesised the 1,4 disubstituted 1,2,3 triazoles derivatives through click reaction and characterised by 1HNMR, Mass and IR data. These synthesized compounds were evaluated for antibacterial activity against Bacillus substillus, Escherichia coli and Staphylococcus aureus. The results obtained are tabulated. The antibacterial results revealed that majority of compounds exhibits good activity against the selected strains. The substituent on triazole nucleus also plays an important role in antibacterial activity.

N O 3 N N R3 R N 3 O R Click Reaction 4

R4 R5 R1 R2 R5 R2 R1

10 Examples Synthesis of 1,4 disubstituted 1,2,3 triazoles

References:

1. Kolb, H.C., Finn, M.G., Sharpless, K.B. Angew. Chem. Int. Ed. 2004, 40. 2. Celik, F., Unver, Y., Barut, B., Ozel, A., Sancak, K. Medicinal Chemistry. 2018, 3. 230. 3. Alvarez, B.J.,Vaquero, J.J., Barluenga, J. Modern heterocyclic Chemistry, 2011, 2. Wiley, Weinheim, 989. 4. Kamal, A., Shankaraiah, N., Devaiah, V. Bioorg. Med. Chem. Lett. 2008. 18, 1468.

151

P60: Cu(I)-Catalyzed Ligand-free Tandem One Pot or Sequential Annulation via Knoevenagel Intermediate: An Entry into Multifunctional Naphthalenes, Phenanthrenes and Quinolines

Adula Kalyani, Rajnikanth Sunke and K. C. Kumara Swamy*

School of Chemistry, University of Hyderabad, Hyderabad 500 046, Telangana, India.

Polysubstituted carbocycles/ heterocycles have widespread applications in pharmaceutical and agrochemical fields.1-2 Copper catalyzed coupling reactions are well-known, but their application for the synthesis of polysubstituted carbocycles/ heterocycles is rather limited.3-4 We have developed a simple and efficient methodology for the construction of multifunctional naphthalenes, phenanthrenes and quinolines through o-bromoaromatic aldehydes and nitriles/esters containing an active methylene group via Knoevenagel condensation, C-arylation and decarboxylation followed by aromatization/ cyclization via copper-catalysis, all in one pot.5 The prepared phenanthrenes compounds are fluorescence active.

References:

1. Xu, X.; Shang, R.; Cai, Z.; Zhao, X. Phys. Chem. Chem. Phys. 2009, 11, 8560. 2. Koppanathi, N.; Kumara Swamy, K. C. Org. Biomol. Chem. 2016, 14, 5079. 3. (a) Ma, D.; Cai, Q. Acc. Chem. Res. 2008, 41, 1450. (b) K. Kunz, U. Scholz, D. Ganzer, Synlett, 2003, 2428. 4. Panda, N.; Mothkuri, R.; Pal, A.; Paital, A. R. Adv. Synth. Catal. 2013, 255, 2809. 5. Sunke, R. Kalyani, A. Kumara Swamy K. C. J. Org. Chem. 2020, 0000 (Just accepted).

152

P61: APPLICATIONS OF LUMINESCENT LANTHANIDE HYDROGELS IN AMINE VAPOR SENSING

Dipankar Bhowmik, Mitasree Maity and Uday Maitra*

Department of Organic Chemistry, Indian Institute of Science, Bengaluru

“Luminescent” lanthanides have intrinsically low molar absorption coefficients, but this problem can be addressed by complexing the lanthanide ions with suitable chelating ligands which improve the luminescence properties drastically.1 A simpler way to sensitize lanthanides which avoids laborious synthetic steps has been developed in our group. This involved the doping of 2,3- dihydroxynaphthalene (DHN) in terbium cholate, and pyrene in europium cholate hydrogels which resulted in significantly enhanced luminescence.2,3 Our recent studies revealed that several biphenyl derivatives could also sensitize Tb(III) in terbium cholate hydrogels. We have used such as system for developing a luminescence turn-off response for detecting hazardous amine vapors.4 When terbium cholate gel doped with a biphenyl derivative was exposed to various amine vapors, luminescence quenching was observed. Interestingly, the quenching was selective to amine and nitro compounds only.2 Appreciable quenching was observed even at low ppm levels of the analytes. We have simplified this detection method by using a low-cost, user-friendly paper based approach for easy detection of the analytes.

Scheme: Sensitization of Tb(III) and Eu (III) luminescence in the presence of micro-molar concentration of sensitizer.

References:

1. Bünzli, J.C.; Piguet, C. Chem. Soc. Rev. 2005, 34, 1048. 2. Kandanelli, R.; Sarkar, A.; Maitra, U. Dalton Trans. 2013, 42, 15381. 3. Banerjee, S.; Kandanelli, R.; Bhowmik, S.; Maitra, U. Soft Matter. 2011, 7, 8207. 4. Shen, X.; Yan, B. J. Mater. Chem. C. 2015, 3, 7038.

153

P62: Low cost paper based sensors for (bio) analyte sensing using terbium photoluminescence

Shruthi Sakthivel, Tumpa Gorai and Uday Maitra*

Department of Organic Chemistry, Indian Institute of Science, Bengaluru

Efficient methods for the rapid detection of (bio) analytes are in great demand. In this direction, paper based sensors have attracted attention for their low cost, biocompatibility, biodegradability and easy availability.1 In the recent years, lanthanide ions have been extensively used as probes in various detection systems due to their long excited lifetimes and sharp almost line like emission. However, they have low emission intensities due to their intrinsic low molar absorptivities.2 Our group has addressed this problem by simply doping an appropriate organic molecule in a lanthanide cholate gel matrix, which improved their luminescence property drastically. For instance, doping micromolar concentration of 2,3-dihydroxy naphthalene (DHN) in terbium cholate (TbCh) hydrogel resulted in enhanced luminescence.3 Recently, we discovered that gallic acid and its esters could also sensitize Tb (III) similarly in TbCh gel. We have used such sensitized luminescence in developing a simple strategy involving a luminescence turn-on response for the rapid detection of gallate derived antioxidants in green tea extracts and a biologically important enzyme - β-glucuronidase (scheme A). TbCh gel coated paper discs4 showed linear luminescence response with the increasing addition of gallate derived moieties. Therefore, these gel coated paper discs were used for the detection of total gallated polyphenol content in various green tea samples with good selectivity and sensitivity. On the other hand, DHN was suitably modified with a sugar unit such that the free sensitizer was released upon the action of β-glucuronidase resulting in enhanced green emission. This enzyme detection method showed good selectivity in the presence of other enzymes and detection limits in nanomolar range. Overall, this method serves as an efficient tool for the easy detection of analytes in various natural and biological samples without interferences from autofluorescence of the samples.

Scheme A: TbCh gel coated paper discs for analyte sensing.

References:

1. Yetisen, A. K.; Akram, M. S.; Lowe, C. R. Lab on a Chip. 2013, 13, 2210. 2. Bünzli, J. C. G. Chem. Rev. 2010, 110, 2729. 3. Banerjee, S.; Kandanelli, R.; Bhowmik, S.; Maitra, U. Soft Matter 2011, 7, 8207. 4. Gorai, T.; Maitra, U. ACS Sensors 2016, 1, 934.

154

P63: Biogenic ZnO NPs: TL emission and direct sunlight assisted selective photodegradation of cationic dyes

Anupama R Prasad, Shamsheera K O, Julia Garvasis and Abraham Joseph*

Department of Chemistry, University of Calicut, Calicut University P O, Kerala, India

Nano Zinc Oxide (ZnO NPs) is a popular photocatalyst and versatile semiconducting material for energy, environmental and biomedical applications [1-3]. Herein, we have developed ZnO nanoparticles via Abelmoschus esculentus (okra) mucilage assisted green strategy without employing additional solvents or stabilizers. The nanoaprticles obtained with good crystallinity and purity with average size of 70 nm with variable morphology. The optical band gap was determined to be 3.12 eV. Thermoluminescence (TL) emission was monitored with variable dosage of gamma radiation. The photodegradation of the material was investigated under direct sunlight and UV light irradiation with a set of organic dyes. A selective degradation of cationic dyes Methylene Blue (MB) and Rhodamine B (RhB) has been observed due to the negative surface charge of ZnO catalyst (-38.37 eV). The dyes were completely removed from their aqueous solutions within 35-40 minutes under direct sunlight and the catalyst was more active under the sunlight than UV light irradiation. The scavenger effects were immensely perceptible for molecular oxygen>electrons> holes. The catalyst was recovered and reused for four consecutive cycles retaining remarkable degradation efficiency.

Fig 1.

References:

1. Anupama, R. P.; P. Rugmini, A.; Joseph, A. Matter. Res. Bull. 2018, 102, 116-121. 2. Anupama, R. P.; Sabeel, M. B.; Linda, W.; Joseph, A. Int. J. Biol. Maromol. 2019, 139, 712 - 718. 3. Bala, N.;Saha, S.;Chakraborty, M.; Maiti,M.;Das, S.; Basu, R.;Nandy, P. RSC Adv. 2015, 5, 4993–5003.

155

P64: Structural elaboration of 1H-indole-2,3-dione and its evaluation as potent agrochemicals

Komalpreet Kaur, Lovepreet Kaur, Samita and Divya Utreja

Department of Chemistry, Punjab Agricultural University, Ludhiana, Punjab-141004

1H-Indole-2,3-dione or isatin and its derivatives are the prominent N-heterocyclic bioisosteres due to their intrinsic versatility they poised them as true cornerstones in pharmaceutical and agricultural industry. They are the perfect tail for design and development of promising plant growth regulators, herbicides, fungicides, antibacterial agents etc. Regioselective elaboration of isatin at N-1 and C-3 poisitions were carried out using phase transfer catalyst- Tetrabutyl ammonium hydrogen sulfate (TBAHS) and Grignard reagents respectively. The synthesized compounds were characterized using various spectral techniques. Isatin and its derivatives were evaluated as antinemic, antimicrobial and antioxidant agents. The biological screening of compounds identified them as true drugs with remarkable activity and selectivity. Further, the compounds were subjected to structure activity relationship studies through various in silico studies. Therefore, studies have been carried out for synthesis and designing of new drugs in pharmaceutical and agricultural industry.

References:

1. Singh, G. S.; Desta, Z. Y. Isatins as privileged molecules in design and synthesis of Spiro- fused cyclic frameworks. Chem. Rev., 2012, 112, 6104. 2. Moradi, R.; Ziarani, G.M.; Lashgiri, N. Recent applications of isatin in the synthesis of organic compounds. Arkivoc, 2017, 1, 148.

156

P65: Fe/Fe3O4@Covalent Organic Framework as Lightweight Nanomagnets

Kaleeswaran D,a Rinku Kushwaha,a, b Sattwick Haldar,a, b Debanjan Chakraborty,a, b Dinesh Mullangi,a, bAditya Borah,c Ramaswamy Murugavelc and Ramanathan Vaidhyanathana, b a Department of Chemistry, Indian Institute of Science Education and Research, Pune, 411008 India. bCentre for Energy Science, Indian Institute of Science Education and Research, Pune, 411008 India c Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076 India.

Two dimensional (2D) Covalent Organic Frameworks (COFs) are made of light atoms such as C, N, O, B and H with significant void/framework ratio, this makes them excellent low-density supports for various metal nanoparticles. 1 Their ordered one dimensional (1D) pores offer high surface area favoring uniform dispersion of the magnetic nanoparticles like Fe3O4 and Co/Co(OH)2 without conceding their intrinsic property.2 The organic nature of such composite facilitate their amalgamation with bulk materials such as paper/textile to enable lightweight nanomagnetic materials which carry potential in several defense and next-generation aviation applications.

References:

1. (a) Kaleeswaran, D.; Antony, R.; Sharma, A.; Malani, A.; Murugavel, R., ChemPlusChem 2017, 82, 1253; (b) Chakraborty, D.; Nandi, S.; Mullangi, D.; Haldar, S.; Vinod, C. P.; Vaidhyanathan, R., ACS Appl. Mater. Interfaces 2019, 11, 15670; (c) Chakraborty, D.; Nandi, S.; Illathvalappil, R.; Mullangi, D.; Maity, R.; Singh, S. K.; Haldar, S.; Vinod, C. P.; Kurungot, S.; Vaidhyanathan, R., ACS Omega 2019, 4, 13465. 2. (a) Li, Y.; Yang, C.-X.; Yan, X.-P., Chem. Commun. 2017, 53, 2511; (b) Mullangi, D.; Chakraborty, D.; Pradeep, A.; Koshti, V.; Vinod, C. P.; Panja, S.; Nair, S.; Vaidhyanathan, R., Small 2018, 14, 180.

157

P66: The Halogen Bond: An Efficient Tool for Electron Catalyzed C-I and C-S Bond Formation at Room Temperature

Anuradha Nandy, G. Sekar*

Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India

Halogen bond (XB) refers to the attractive noncovalent interactions between terminal halogen atoms in compounds of the type R-X (X = Cl, Br, I; R = electron withdrawing group) and Lewis bases (LB).1 Recently, we have developed new XB donor catalysts for several transition metal-free organic reactions where halogen-bonded halogen(I) species act as key intermediates with unusual reactivity and selectivity.2 For the first time, the halogen-bond has been employed as an efficient tool to enable an electron-catalyzed regioselective iodination of hetero-aryls under mild reaction conditions.3 The halogen bond between hetero-aryl substrates (electron-donor) and iodine (electron-acceptor) lowers the activation energy of the electron-transfer (ET) from the former to the latter.4 Taking this methodology a step further, a one pot synthesis of heteroaryl thioethers has been carried out under visible light condition.5 The formation of halogen bond and the regioselectivity of the reaction have been demonstrated with several control experiments, spectroscopic analysis and quantum chemical calculations.

Scheme 1. XB-assisted visible light driven C-S bond formation of various heteroarenes at room temperature.

References:

1. a) Desiraju, G. R.; Ho, P. S.; Kloo, L.; Legon, A. C.; Marquardt, R.; Metrangolo, P.; Politzer, P.; Resnati, G.; Rissanen, K. Pure Appl. Chem. 2013, 85, 1711. 2. a) Kazi, I.; Guha, S.; Sekar, G. Org. Lett. 2017, 19, 1244. b) Guha, S.; Kazi, I.; Mukherjee, P.; Sekar, G. Chem. Commun. 2017, 53, 10942. c) Guha, S.; Kazi, I.; Nandy, A.; Sekar, G. Eur. J. Org. Chem. 2017, 5497. 3. Kazi, I.; Guha, S.; Sekar, G. J. Org. Chem. 2019, 84, 6642. 4. Rosokha, S. V.; Vinakos, M. K. Phys.Chem.Chem.Phys. 2014, 16, 1809. 5. Nandy, A.; Kazi, I; Guha, S.; Sekar, G. (Manuscript submitted).

158

P67: Chemoenzymatic Approach gives New Insight into Rugulosin Biosynthesis

Nirmal Saha, Syed Masood Husain*.

Molecular Synthesis and Drug Discovery Unit, Centre of Biomedical Research SGPGIMS Campus, Raebareli Road, Lucknow 226014 (India)

Modified bisanthraquinone, (–)-rugulosin (1) isolated first from P. Islandicum Sopp[2] is a complex dimeric natural product with diverse biological activities.[1] Early studies using feeding experiments has established emodin (2) as a biosynthetic precursor for (–)-rugulosin biosynthesis along with several proposed intermediates. In recent years, we have developed a chemoenzymatic, biomimetic strategy to synthesize (–)-rugulosin (1) in three steps starting from emodin (1). This has also resulted in the isolation and characterization of many putative biosynthetic intermediates such as 3,4- dihydroemodin (3), (–)-flavoskyrin (4) and a dimeric intermediate 5 which gives further insight into the biosynthesis of (–)-rugulosin (1). For the first time, the 3,4-dihydroemodin (3) is obtained by the oxidation of a reduced emodin hydroquinones synthesized by the reduction of emodin (2) catalyzed by an NADPH dependent anthrol reductasefrom Talaromyces islandicus (ARti) in the presence of [3] Na2S2O4. In addition, we have synthesized intermediate 5 using (–)-flavoskyrin (4) obtained through dimerization of 3,4-dihydroemodin (3). Finally, the conversion of 4 into (–)-rugulosin (1) via putative biosynthetic intermediates supports its role in the newly proposed biosynthetic pathway. The study presented here will provide vital clues for the biosynthesis of related bisanthraquinones isolated from fungi in future.

References:

1. Nakamura, S.; Nii, F.; Shimizu, M.; Watanab, I. Japan. J. Microbiol. 1971,15, 113-120. 2. Seo, S.; Ogihara, Y.; Sankawa, U.; Shibata, S. Tetrahedron Lett. 1972, 13, 735-736. 3. Singh, S. K.; Mondal, A.; Saha, N.; Husain, S.M. Green Chem., 2019,21, 6594-6599.

159

P68: Novel Iron Chelators for the Treatment of Alzheimer‟s Disease

P. Duraippandi†#, Zhixuan Wu†, Nady Braidy§, Nor Hawani Salikin&, Suhelen Egan&, Michael L. H. Huang†, and Des R. Richardson†*

†Department of Pathology, The University of Sydney, Sydney, New South Wales, 2006, Australia. §School of Psychiatry, University of New South Wales, Sydney, 2031, Australia. &Centre for Marine Science and Innovation, University of New South Wales, Sydney, 2031, Australia. #Department of Chemistry, Central University of Karnataka, Gulbarga-585367, India.

Alzheimer‟s disease (AD) is a multi-factorial condition that leads to cognitive decline and represents a major global health challenge in ageing populations.1 The lack of effective AD therapeutics led us to develop multi-functional nicotinoyl hydrazones2 to target multiple pathological AD hallmarks. The most active analogue among 20 is 6-methoxysalicylaldehyde nicotinoyl hydrazone (SNH6) which demonstrated: (1) low cytotoxicity; (2) potent iron (Fe)-chelation efficacy; (3) significant inhibition of copper-mediated Aβ aggregation; (4) oxidative stress alleviation; (5) effective donation of NAD+ to NAD-dependent metabolic processes (PARP and sirtuin activity) and enhanced cellular NAD+ /NADH ratios, as well as significantly increased median C. elegans lifespan (1.46-fold of the control); (6) partially decreased BACE1 expression, resulting in significantly lower soluble amyloid precursor protein-β (sAPPβ) and Aβ 1-40 levels; and (7) favourable blood-brain barrier-permeation properties (Scheme 1). Structure-activity relationships demonstrated the ability of our nicotinoyl hydrazones to increase NAD+ was dependent on the electron-withdrawing or -donating substituents on the aldehyde- or ketone-derived moiety. Aldehyde-derived hydrazones containing the ONO-donor set and electron- donating groups were required for NAD+-donation and low cytotoxicity. This study highlighted the potential of nicotinoyl hydrazones, particularly SNH6, to act as multi-functional therapeutics and delivery vehicles for NAD+-precursors for AD treatment.

High Fe ROS chelation efficacy

Lifespan BACE1 Aβ

SNH6

Cu-mediated Aβ NAD+/NADH aggregation

Scheme 1: Multifunctional activity of SNH6 to Alzheimer‟s disease.

References:

1. LaFerla, F. M.; Oddo S. Trends Mol. Med. 2005, 11, 170. 2. Kalinowski, D.S.; Richardson D. R. Pharmacol. Rev. 2005, 57, 547.

160

P69: Cu-Catalyzed One-pot Synthesis of Thiochromeno-quinolinone and Thiochromeno- thiochromenone via Double Hetero Michael Addition Using In-situ Generated Nucleophiles

N.Sundaravelu and G.Sekar*

Department of chemistry, Indian Institute of Technology Madras, Chennai, Tamilnadu-600036, India

4-Quinolone has been well recognized as a privileged scaffold prevalent in a vast array of natural products and biologically active compounds.1 Although the aforementioned methods provided effective synthetic routes to a wide variety of 4-quinolones, 2 the use of expensive catalysts or pre- functionalized starting materials, which often require multi-steps preparation and waste halogen by- products have limited their applications to some extent. As part of our ongoing research towards Cu- catalyzed in-situ generation of thiol using xanthate as sulfur surrogate,3 a copper catalyzed one-pot synthesis of thiochromeno[4,3-b]quinolin-7-one via double hetero Michael addition using in-situ generated sulfur followed by aza nucleophiles has been reported.4 Further, this method was extended for the synthesis of thiochromeno[4,3-b]thiochromen-7-one via intermolecular followed by intramolecular sulfa-Michael addition. This reaction proceeds through thiolate formation/intermolecular sulfa-Michael addition/ aldol condensation/reduction of nitro group via PCET pathway/aza-Michael addition/further this will be oxidized by in-situ generated iodine from waste by product KI. Experimental studies proved that the nitro group reduction takes place via PCET and in-situ generated iodine plays a key role in the oxidation step.

Scheme: Cu-catalyzed one-pot synthesis of thiochromeno-quinolinone and thiochromeno- thiochromenone via double hetero Michael addition

References:

1. Huse, H.; Whiteley, M. Chem. Rev. 2011, 111, 152. 2. Ma, Y.; Zhu, Y.; Zhang, D.; Meng, Y.; Tang, T.; Wang, K.; Ma, J.; Wang, J.; Sun, P. Green Chem. 2019, 21, 478. 3. Sundaravelu, N.; Sekar, G. Org. Lett. 2019, 21, 6648. 4. Sundaravelu, N.; Sekar, G (manuscript under preparation)

161

P70: Remodelling of Aβ Aggregation by CDP Peptidomimetics Inhibitors

Mouli Konar, Debasis Ghosh, Sourav Samanta and Thimmaiah Govindaraju*

Bioorganic Chemistry Laboratory, New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru 560064, Karnataka, India

Alzheimer's disease (AD) is a major neurodegenerative disorder for which currently there are no diagnosis or treatment. Accumulation of amyloid plagues in the brain and their multifaceted toxicity is considered as pathological hallmarks of AD. Amyloid-β (Aβ) peptides undergo aggregation mainly thr structure supported by hydrophobic interactions of the core recognition region HQKLVFFAED (Aβ14-23).

Disruption of the hydrogen bonding interactions within the β-sheet structure (Aβ42 fibrils) is one the potential routes to inhibit their formation and growth. In this context, we sought to design a new class of peptidomimetics having multiple donor-accepter sites. Our preliminary work showed that cyclic dipeptide (CDP)-based unnatural amino acid (kd) with multiple hydrogen bond donors and acceptors indeed capable of modulating the aggregation process Aβ14-23 albeit over a prolonged period of incubation. Subsequently, kd was incorporated into Aβ14-23 at predetermined positions and the derived

CDP-peptidomimetics were found to effectively modulated the fibrillation process of Aβ14-23 when monitored at two pH (2 and 7.4) conditions. A detailed biophysical study indicated that the conformational transition (between random coil to β-sheet via α-helix) of Aβ14-23 is restricted to α-helical conformation at pH 7.4 in the CDP-peptidomimetics which control the growth of nucleated intermediates to inhibit the toxic aggregation species. These result encouraged us to investigate the effect of CDP-peptidomimetics on the aggregation propensity of Aβ42 peptide and it has been found that the CDP-peptidomimetics act as good inhibitors of Aβ42 fibrillation under physiological conditions. Further, in cellulo results were found to be in good agreement with the in vitro studies. Overall, these results hold significant promise towards the advancement of our understanding of the AD pathology and development of potential therapeutics.

References:

1. Rajasekhar, K.; Chakrabarti, M.; Govindaraju, T. Chem. Commun. 2015, 51, 13434. 2. Knowles, T. P. J.; Vendruscolo, M.; Dobson, C. M. Nature Rev. Mol. Cell Biol. 2014, 15, 384.. 3. Madhu, C.; Voshavar, C.; Rajasekhar, K.; Govindaraju, T. Org. Biomol. Chem. 2017, 15, 3170. 4. Manchineella, S.; Govindaraju, T. Chempluschem. 2017, 82, 88. 5. Rajasekhar, K.; Madhu, C.; Govindaraju, T. ACS Chem. Neurosci. 2016, 7, 1300. 6. Rajasekhar, K.; Narayanaswamy, N.; Mishra, P.; Suresh, S. N.; Manjithaya, R.; Govindaraju, T. ChemPlusChem. 2014, 79, 25. 7. S. Samanta, K. Rajasekhar, V. Babagond, T. Govindaraju, ACS Chem. Neurosci. 2019, 10, 3611.

162

P71: Open Chain Pyrrole Based Ligands and Their Coordination Complexes

Sabari Panchavarnam, Kishor G. Thorat and Mangalampalli Ravikanth*

Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.

Among the fluorescent dyes, the boron-dipyrromethene (BODIPY) dyes are popular because the BODIPY dyes have remarkable characteristics such as high absorption coefficients, high fluorescence yields, long excited state lifetime, good solubility in organic solvents with excellent photo stability 1. The presence of additional pyrrole ring at the α-position of BODIPY are called α-pyrrolyl BODIPY which shows better photophysical and electrochemical properties compared to BODIPYs 2. The α- pyrrolyl dipyrrins can be prepared by demasking BF2 group of α-pyrrolyl BODIPYs. The α-pyrrolyl dipyrrins containing three pyrrole „‟N”s can act as good ligands to form interesting metal complexes. Interestingly, the reports on metal complexes of pyrrolyl dipyrrins are very few because of lack of proper synthetic approaches to obtain pyrrolyl dipyrrin ligands 3. In this poster, we present our successful synthesis of helical bis Cu(II) complex (I) of open chain hexapyrrolic ligand under simple reaction conditions (manuscript under preparation). In addition, we also present the synthesis and properties of a series of BR2 complexes of α-pyrrolyl dipyrrin (II) which were synthesized from BF2 complex of α-pyrrolyl dipyrrin (α -pyrrolyl BODIPY) by treating it with various alkyl- and aryl magnesium halides under mild Grignard reaction conditions4. Furthermore, we also present out recent resulst on meso- pyrrolyl BODIPY-Schiff base conjugate (III) as a specific colorimetric optical sensor for Cu(II) ion (manuscript under preparation).

(I) (II) (III)

R= CH3, C2H5, C4H9 , Phenyl, p-tolyl, p-anisyl.

References:

1. Rao, M. R.; Tiwari, M. D.; Bellare, J.; Ravikanth, M. J. Org. Chem. 2011, 76, 7263. 2. Kaur, T.; Lakshmi, V.; Ravikanth, M. RSC Adv. 2013, 3, 2736. 3. Sharma, R.; Ravikanth, M. Eur. J. Inorg. Chem. 2017, 829. 4. Sabari, P.; Kishor, G. T.; Ravikanth, M. Tetrahedron. 2019, 75, 3371.

163

P72: THE MICRO MACRO PARADOX IN INDUCED FIELD CALCULATIONS AND THE ROLE OF HR SOLID-STATE NMR

S.Aravamudhan

Department of Chemistry.North Eastern Hill University

A magnetized specimen can be divided into regions referred to as „discrete‟ and „continuum‟ regions in the context of accounting for the induced field [1] at a specified point. For calculations of contributions to induced fields it becomes necessary to consider the magnetic moments of microscopic or semi micro quantities within the specimen which manifest as the macroscopic magnetization of the material. The magnetic moments can be envisaged to result from a corresponding charge circulation and consider the magnetic moments as arising from magnetic susceptibility that is experimentally measured or theoretically calculated. These magnetic moments in turn induce magnetic fields at any specified point. The procedure for electrical charge polarizations is applicable in this case of induced magnetic fields and the familiar treatment of local fields is due to Lorentz. For these calculations becomes necessary to consider a fictitious spherical cavity within the material around the specified point which is considered as a discrete region. With all the careful considerations there seems to be an average field within a cavity (where the material has been removed) and to simplify the matter the cubic symmetry is invoked to assume the induced field zero within the carved out spherical region. These considerations give rise to an apparent possibility of including twice some way the carved out spherical region around the site and making amends at the end of the calculations, when the field is non-uniform [2]. This complication has led to publications [3,4] which try to explain this paradox. A clarification from the HR PMR results on a single crystal specimen provides much more clarity on this apparent paradoxical situation pointed out earlier.

References:

1. Magnetized Materials: Contributions inside Lorentz Ellipsoids. S. Aravamudhan, Indian Journal of Physics,. 2005, Volume 79 (9), 985. 2. http://nehuacin.tripod.com/id3.html (4th Alpine Conference on SSNMR,2004) 3. Local Field Effects and Effective-medium Theory, D.E. Aspnes, American Journal of Physics, 1982, 50(8), 704. 4. Local Fields in Solids: microscopic aspects of dielectrics, S.E Schnatterly and C. Torio, Reviews of Modern Physics, 1992, 64, 619.

164

P73: Polyampholyte as a modulator of amyloid aggregation and lithium ion carrier

Lakshmi Priya Datta, Sourav Samanta and Thimmaiah Govindaraju*

Bioorganic Chemistry Laboratory,New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P. O., Bengaluru-560064, Karnataka, India.

Misfolding and aggregation of peptides and proteins is one of the pathological hallmarks of Alzheimer‟s disease (AD). The etiopathogenesis of AD involve the accumulation of insoluble amyloid- β (Aβ) plaques in the brain, which disrupt the neuronal network and communication, cause neuronal death and severe cognitive impairment. Modulation of Aβ aggregation by exogenous therapeutically active substances is considered as effective strategy to contain the AD progression. Zwitterionic polymers and polyampholytes are considered as artificial protein mimic systems which are capable of inhibiting the protein aggregation. In our macromolecule-based aggregation-inhibition strategy, tryptophan-methacrylic acid (PTMA) based polyampholyte (block co-polymer with cationic and anionic segments) is synthesized through reversible addition fragmentation chain transfer (RAFT) polymerization technique. PTMA is found to effectively modulate the Aβ aggregation and rescue neuronal cells (SHSY5Y cells) from Aβ-induced neurotoxicity as compared to the cationic and anionic individual homopolymeric segments. Lithium has been reported to exhibit therapeutic role in chronic neurological diseases including AD. PTMA sequester lithium ion and release in response to stimuli and can be used as a carrier of lithium for the targeted delivery. These studies have demonstrated that the dual action PTMA has the potential to be developed into therapeutic candidate for AD.

References:

1. Rajasekhar, K., Chakrabarti, M., Govindaraju, T. Chem. Commun., 2015, 51, 13434. 2. Prince, M., Bryce, R., Albanese, E., Wimo, A., Ribeiro, W., Ferri, C. P. Alzheimer's Dement. 2013, 9, 63. 3. Rajasekhar, K., and Govindaraju, T. RSC Adv. 2018, 8, 23780. 4. Sun, H., Liu, J., Li, S., Zhou, Li., J. Wang, L. Liu, F. Lv, Q. Gu, B. Hu, Y. Ma, Wang, S. Angew. Chem. Int. Ed. 2019, 58, 5988. 5. Samanta, S., Rajasekhar, K., Govindaraju, T. ACS Chem. Neurosci. 2019, 10, 3611. 6. Samanta, S., Govindaraju, T. ACS Chem. Neurosci. 2019, 10, 4847.

165

P74: Detection Of Host-Guest Supramolecular Inclusion Complexation of Oxime Functionalized Ionic Liquids and Cyclodextrins

Subhashree Jayesh Pandya, Kallol K Ghosh*

School of Study in Chemistry, Pt. Ravishankar Shukla University, Raipur 492010 (C.G.)

Host-guest complexation between oxime functionalized ionic liquids (ILs) (S)-2- ((hydroxyimino)methyl)-1-(2-((1-(octylamino)-1-oxo-3-phenylpropan-2-yl)amino)-2-oxoethyl)pyridin-1- ium bromide (2-PyPheC8), (S)-3-((hydroxyimino)methyl)-1-(2-((1-(octylamino)-1-oxo-3-phenylpropan- 2-yl)amino)-2-oxoethyl)pyridin-1-ium bromide (3-PyPheC8) and (S)-4-((hydroxyimino)methyl)-1-(2-((1- (octylamino)-1-oxo-3-phenylpropan-2-yl)amino)-2-oxoethyl)pyridin-1-ium bromide (4-PyPheC8) and cyclodextrins (α and β CDs) has been studied. The formation of inclusion complexes (ICs) were confirmed by UV–Vis and FT-IR which revealed formation of 1:1 stoichiometry. The binding constant of ICs complex was determined by Job's plot method. Thermodynamic parameters like enthalpy (ΔH), entropy (ΔS) and Gibb‟s free energy (ΔG) were also calculated. The results have also been validated by 1H NMR, COSY and NOESY methods. The H-bonding, electrostatic force and hydrophobic interactions involved in the formation of complexations. The application related to the antidepressant drugs and inclusion complexes have also been studied.

References:

1. Banjare, M. K.; Behera, K.; Satnami, M. L.; Pandey S.; Ghosh, K. K.; Chem. Phys. Lett. 2017, 689, 30. 2. Gao, Y.; Zhao, X.; Dong, B.; Zheng, L.; Li N.; Zhang, S. J. Phys. Chem. B 2006, 110, 8576. 3. Yu, G.; Hua B.; Han C. Org. Lett. 2014, 16, 2486.

166

P75: Charge transfer dynamics and stability enhancement in inorganic halide Perovskite solar cells

Samita Mishra, Arijit K. De*, Debrina Jana*

Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali Sector 81, Mohali, Punjab 140306, India.

Hybrid perovskite solar cell technology has attracted incredible interest owing to its both high conversion efficiency and low processing cost. This emerging technology achieved lab-scale device efficiency more than 22% by improving the quality of interfaces, carrier transport layers and perovskite films and substantial steps are being made towards commercialization. Increasing the stability of the perovskite to make it suitable for long time usage in ambient atmosphere along with understanding the charge transport property in the device is the most relevant challenging step to be undertaken.

α-CsPbI3 perovskite, the black cubic phase has already been established as a good photovoltaic active material. This is not stable at room temperature and even if it is prepared and get stabilized at high temperature, it readily degrades to non-perovskite yellow colour orthorhombic phase. Herein, we will describe the synthetic protocol of α-CsPbI3 perovskite nanocrystals inside a mesoporous alumina thin film. The active phase of CsPbI3 remains intact after taking the film at room temperature and ambient condition and the stability persists for a month. PVP used in CsPbI3 precursor solution preparation helps to synthesize and stabilize the cubic phase at room temperature by lowering the surface tension. After formation of CsPbI3, electron and hole transport layers were used to separate the charges to avoid charge recombination and femtosecond broadband transient absorption spectroscopy was utilized to investigate the charge transfer kinetics of as synthesized mesostructured perovskite. The spectral data confirms the efficient charge transfer occurs from CsPbI3 to charge conducting layers.

References:

1. Li, B.; Zhang, Y.; Fu, L.; Yu, T.; Zhou, S.; Zhang, L. and Yin L. Nat. Commun. 2018, 9, 1076. 2. Lee, M. M.; Teuscher, J.; Takurou, T. M.; Murakami, N. and Snaith, H. J. Science 2012, 338, 643. 3. Takhellambam, D.; Meena, T. R. and Jana, D., Chem. Commun. 2019, 55, 4785. 4. Mondal, N. and Samanta A. Nanoscale 2017, 9, 1878. 5. Manser, J. S. and Kamat,, P. V. Nature Photonics 2014, 8, 737.

167

P76: Unravelling the role of water in ultrafast excitation energy transfer within nano- architectures of chlorophyll a

Yogita Silori, Sakshi Chawla and Arijit K. De*

Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140 306, India.

The mechanism of excitation energy transfer (EET) in natural light harvesting systems which includes absorption of light energy by antenna chromophores followed by the exchange of energy among various chromophores with near-unit efficiency and finally funneling of energy towards the reaction center where it is trapped leading to a charge separation, has attracted high interest [1,2]. The architectural principle of chromophore-protein complexes is too complicated to be replicated in artificial light-harvesting devices. However, numerous interesting works are done in designing supramolecular architectures that mimic the organization of various chromophores within the photosynthetic antenna complex of green sulfur bacteria, called chlorosome [3]. Chlorophyll a is the highest utilized photosynthetic pigment due to its efficient absorption of red light and its redox properties. Interaction between chlorophyll molecules (and also with its local environment) gives rise to formation of various architectures like polymer (cylindrical reverse micelle), aggregates (T-shaped oligomers which form micelles), etc. by varying the ratio of acetonitrile (ACN) and water [4]. We studied ultrafast excited state dynamics of these architectures using femtosecond pump-probe spectroscopy to unravel the structure-function relationship mediated via water molecules. All the architectures show a broad excited state absorption (ESA) band in the region of 490-650 nm which show no significant change in spectral traces with increasing probe delay, in ACN. However, in the other two cases (mixtures of ACN/water), the ESA band shows a blue shift as well as spectral narrowing with the pump-probe delay; this clearly indicates presence of vibrational cooling which takes place due to faster thermal diffusivity in presence of water. Quite interestingly, the vibrational cooling is followed by stimulated emission with almost no red shifts in spectra, suggestive the absence of significant polar solvation dynamics.

References:

1. R.E. Blankenship, Molecular Mechanisms of photosynthesis, Blackwell Science Ltd., USA, 2002. 2. R. E. Blankenship and K. Matsuura, in Advances in Photosynthesis and Respiration, ed. B. R. Green and W. W. Parson, Springer, Arizona, 2003, vol. 13, ch.6, pp. 195-217. 3. T. S. Balaban, Acc. Chem. Res., 2005, 38, 612–623. 4. A. Agostiano, P. Cosma, M. Trotta, L. Monsù-Scolaro and N. Micali. J. Phys. Chem. B, 2002, 106, 1282012829.

168

P77: Color Tuning of Mixed Lanthanide Triggered by pH

Manaranjan Sahu, Ajay Kumar, and Uday Maitra*

Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012

In this poster, we will present the pH-dependent sensitization of Tb(III) using methyl salicylate (MS). Methyl salicylate was found to be a specific sensitizer for Tb(III) but not for Eu(III). Subsequently, doping of Eu(III) in a mixture of Tb(III) and MS resulted in color change from green to orange depending upon the pH of the solutions. Photophysical studies confirmed energy transfer from Tb(III) to Eu(III) in the lanthanide mixed Tb(III)/Eu(III)-MS system.

Day light

Tb(III)/Eu(III) pH 6 pH 7 pH 8 pH 9 9:1

UV light

References:

1. Bhowmik; S.; Maitra, U. Chem. Commun. 2012, 48, 4624-4626. 2. Banerjee, S.; Kandanelli, R.; Bhowmik, S.; Maitra, Soft Matter 2011, 7, 8207-8215. 3. Brittain, H. G. Inorg. Chem. 1979, 18, 1740-1745.

169

P78: CATALYST FREE SYNTHESIS OF 3,1-BENZOXATHIIN-4-ONES/1,3-BENZODIOXIN-4-ONES

M. Malarvizhi and S. Muthusamy*

School of Chemistry, Bharathidasan University,Tiruchirappalli-620024, Tamilnadu

Heterocycles form the largest of classical divisions of organic chemistry and are of immense importance biologically and industrially. One striking structural feature inherent to heterocycles,1 which continues to be exploited to great advantage by the drug industry, lies in their ability to manifest substituents around a core scaffold in defined three dimensional representations. Between them, sulfur and oxygen containing heterocyclic compounds have maintained the interest of researchers through decades of historical development of organic synthesis.2 Resulting from the derivation of homocyclic hydrocarbons from the substitution of the ring carbon atom by sulfur heteroatom, their relevance comes from the significant changes in cyclic molecular structure engraved by differences in electronic configuration, unshared pair of electrons and ultimately the electronegativity between heteroatoms and carbon.3 From the literature, we observed that 3,1-benzoxathiin-4-ones4 / 1,3- benzodioxin-4-ones were commonly synthesized by the inter- and intramolecular metal catalyzed cyclizations of alkynes and thiosalicylic acids / salicylic acids. To the best of our knowledge, there is no report available for the synthesis of these systems using propargyl alcohols. We herein demonstrate the reaction of thiosalicylic acid / salicylic acid and propargylic alcohols 1 for the synthesis of 3,1-benzoxathiin-4-ones / 1,3-benzodioxin-4-ones 2 and 3 without using any catalyst. The details of this reaction will be discussed.

Scheme: Synthesis of 3,1-benzoxathiin-4-ones 2 / 1,3-benzodioxin-4-ones 3

References:

1. Dua, R.; Shrivastava, S.; Sonwane, S. K.; Srivastava, S.K. Advan. Biol. Res. 2011, 5, 120. 2. Valverde, M. G.; Torroba, T. Molecules 2005, 10, 318. 3. Marcos, C. F.; Polo, C.; Rakitin, O. A.; Rees, C. W.; Torroba, T. Angew. Chem. Int. Ed. Engl. 1997, 36, 281. 4. (a) Sonehara, T.; Murakami, S.; Yamazaki, S.; Kawatsura, M. Org. Lett. 2017, 19, 4299; (b) Nishina, Y.; Miyata, J. Synthesis 2012, 44, 2607.

170

P79: Facile Synthesis of Fused Sipro Pyrrolidine-oxindole Derivatives via 1,3-Dipolar Cycloaddition of Isatins, α-Amino acids and Heterobicyclic Alkenes

Subramani Kumaran and Kanniyappan Parthasarathy*

Department of Organic Chemistry, University of Madras, Chennai (600025), India

1,3-Dipolar cycloaddition reaction have emerged as highly useful methods for assembling of complex heterocyclic molecules from simple starting materials.1 Particularly, azomethine ylide is a favourable key intermediate to build pyrrolidines, sipro pyrrolidines, 3-spiropyrrolidine oxindoles and pyrrolizidines in a single step with multiple stereocenters.2 Spiropyrrolidine oxindole skeletons are found in a wide range of naturally occurring compounds that shows various unique biological activities.3 We developed a facile synthesis of various fused spiro-pyrrolidine-oxindoles from isatins, amino acids with heterobicyclic alkenes via 1,3-dipolar cycloaddition. For the first time, we used heterobicyclic alkenes as a dipolarophile in 1,3-dipolar cycloaddition of the azomethine ylide generated via decarboxylation. Triflic acid mediated aromatization of cycloaddition products has been demonstrated. A possible mechanism is proposed that the formation of iminium carboxlate intermediate (I), azomethine ylide intermediate (II) via decarboxylation,4 subsequent 1,3-dipolar cycloaddition with oxabenzonorbornadiene to give cycloaddition product.

References:

1. (a) Kanemasa, S. Synlett, 2002, 1371. (b) Gothelf, K. V.; Jorgensen, K. A. Chem. Rev. 1998, 98, 863. 2. (a) Najera, C.; Sansano, J. M. Angew. Chem. Int. Ed. 2005, 44, 6272. (b) Wang, Y.-M.; Zhang, H.-H.; Li, C.; Fan, T.; Shi, F. Chem. Commun. 2016, 52, 1804. 3. Jiang, T.; Kuhen, K. L.; Wolff, K.; Yin, H.; Bieza, K.; Caldwell, J.; Bursulaya, B.; Wu, T. Y.; He, Y. Bioorg. Med. Chem. Lett. 2006, 16, 2105. 4. Bharitkar, Y. P.; Das, M.; Kumari, N.; Kumari, M. P.; Hazra, A.; Bhayye, S. S.; Natarajan, R.; Shah, S.; Chatterjee, S.; Mondal, N. B. Org. Lett. 2015, 17, 4440.

171

P80: Nickel-Catalyzed Synthesis of Substituted Indolo[2,1-a]isoquinolines via Cyclization of 2- (2-bromophenyl)-1H-indoles with Alkynes

Sampath Thavaselvan and Kanniyappan Parthasarathy*

Department of Organic Chemistry, University of madras, Chennai-25 (India)

The nitrogen containing heterocycle such as indole occupies a remarkable role in wide variety of natural products, drug molecules1 and high performance electronic devices.2 Transition-metal catalyzed constructions of various polyaromatic hydrogens (PAHs) by using aryl halides with alkynes have been developed through C-H bond activation.3,4 So far, to the best of our knowledge the formation of C-C and C-N bond formation by using Ni-catalyzed cyclization were less explored in literature. However, the transition metals such as Rh, Pd- catalyzed annulations were well known. Based on the literature survey, we developed a reaction of 2-(2-bromophenyl)-1H-indoles with internal alkynes in the presence of Ni(II)-catalyst/PPh3/Zn to afford the annulated products with good yield. The mechanism believed to proceed an oxidative addition of aryl halides with Ni(0), coordinative insertion of alkynes to give nickel intermediate (I) followed by reductive elimination sequence.

References:

1. (a) Gribble, G. W. In Comprehensive Heterocyclic Chemistry II; Katrizsky, A. R., Rees, C. W., Scriven, E. S. V., Eds.; Pergamon Press: New York, 1996, 2, 207. (b) Le Quesne, P. W.; Dong, Y.; Blythe, T. A. Alkaloids: Chem. Biol. Perspect. 1999, 13, 237. 2. (a) Wang, C.; Dong, H.; Hu, W.; Liu, Y.; Zhu, D. Chem. Rev. 2012, 112, 2208. (b) Dong, H.; Fu, X.; Liu, J.; Wang, Z.; Hu, W. Adv. Mater. 2013, 25, 6158. 3. (a) Shi, Z.; Ding, S.; Cui, Y.; Jiao, N. Angew. Chem., Int. Ed. 2009, 48, 7895. (b) Morimoto, K.; Hirano, K.; Satoh, T.; Miura, M. Org. Lett, 2010, 12, 2068. 4. Wan, D.; Li, X.; Jiang, R.; Feng, B.; Lan, J.; Wang, R.; You, J.; Org. Lett, 2016, 18, 2876.

172

P81: Design and Development of sustainable poly (benzoxazine-co-maleimide) materials for autonomous self-healing applications

S.Sriharshitha,S.Devaraju* and K.Krishnadevi*

Division of Chemistry, Department of Science and Humanities Vignan’s Foundation for Science, Technology and Research (VFSTR), Guntur, India

In this work, an attempt has been made to develop bio-based eco-friendlypoly(benzoxazine-co- maleimide) [EPBz-MA] materialforautonomous self-healing applicationsusing eugenol based benzoxazine (EBz-AEE) and maleic anhydride (MA). EBz-AEE is synthesized using eugenol, aminoethoxyethanol (AEE) and paraformaldehyde through Mannich reaction. Later, EBz-AEE is copolymerized with anhydride precursor(maleic anhydride). The structure of the EBz-AEE is confirmed using Fourier transform infrared (FT-IR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The thermal properties of theEPBz-MA arecheckedusing differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) analysis. Further,the self-healing behavior of the bio-based EPBz-MAis checked with applyingmild external pressure. The developed EPBz-MA shows good and repeated self-healing abilitydue to supra-molecular action and inter and intra hydrogen bonding interactions between carboxylic acid and phenolic hydroxyl groups in the network structure.Thus, the developed cost effective and environment friendly self-healing EPBz-MAmatrices will be useful for further expanding the uses of benzoxazines in various high performance applications including coating, automobile, printed circuit board, and etc. with longer self-life.

O O N OH O H3CO O O AEE +

Maleic anhydride Eugenol CH2 ⁺ Ebz-AEE Δ 60 c to 180 c (20 c/hr)

EPBz

EPBz Damaged EPBz Healed EPBz

References:

1. Fu, F., Huang, M., Zhang, W. et al. 2018 SciRep 8, 10325 2. Liang, J.-Y.; Shin, S.-R.; Lee, S.-H.; Lee, D.-S Polymers 2019, 11, 1674. 3. Cheng, C., Zhang, X., Chen, X. et al.2016J Polym Res 23, 110

173

P82: A Tethered Oxycarbenium Ion Initiated Epoxide Opening Reaction: Sharpless Epoxides to Fully Protected Triols

Meera Johny, Rosemary Philip, Rajendar Goreti*

School of Chemistry, IISER Thiruvananthapuram

A new methodology was proposed based on tethered oxy-carbenium ion initiated epoxide opening to synthesise fully protected triols from 2,3-epoxy alcohols. The conversion happens in two steps using an appended alkoxide as a nucleophile, which is obtained from an acetal-protecting group to yield 5 or 6 membered cyclic acetals as products. The control of regiochemistry of epoxide opening reaction to produce either C3 alkoxylated products or C2 alkoxylated products, fairly depends upon electronic and steric effects of substrate. Also, the epoxide opening found to be highly stereoselective a complete inversion at stereogenic center is observed.

Scheme: Lewis Acid Catalyzed Cyclization of Epoxy Aceta

References:

1. Sharpless, K. Barry, et al. Pure and Applied Chemistry. 1983, 55, 589-604. 2. Hanson, Robert M. Chemical Reviews 1991, 91. 437-475. 3. Vol‟eva, V. B., et al. Russian Journal of Organic Chemistry, 51, 7 ,2015, 915-917.

174

P83: Modulation of Nitric Oxide (NO) Release by Cuprous Oxide (Cu2O) Polymorphs: Crystal- Facet-Dependent Denitrosylation of S-Nitrosothiols

Sourav Ghosh, Punarbasu Roy, Sanjay Prasad and Govindasamy Mugesh*

Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore

Nitric oxide (NO), a gaseous molecule is involved in a variety of important biological processes such as signalling molecule in the nervous system, vasodilator in the cardiovascular system, and it is used as a key molecule by the immune system to fight against infections.1 As NO is synthesized in endothelial cells by eNOS, the low level of NO due to impairment of the enzyme activity affects the endothelial function and signal transduction. On the other hand, elevated levels of NO cause nitrosative stress related signalling, leading to post-translational modification of many proteins, neurotoxicity and apoptosis.1c-e Therefore, the imbalance between the nitrosylation and denitrosylation activities of enzymes affect the NO concentration and show beneficial or deleterious biological effects.

Synthetic compounds such as organic nitrates (RONO2) and nitrites (RONO), metal nitrosyl complexes, N-nitrosamines (RN(NO)R′), S-nitrosothiols (RSNO) have been used to generate NO for biological applications.2a However, the controlled release of NO from the nitrosylated compounds at physiological pH remains a challenge. In this poster, we demonstrate that Cu2O-based nanomaterials can release NO from S-nitrosothiols and provide the first experimental evidence that the denitrosylation activity Cu2O nanocrystals can be altered by changing the crystal facets within the same crystal system.2b The detailed mechanistic investigation revealed that the {111} crystal facet in Oh is more efficient than the {011} and {001} facets present in RDh and cube, respectively, in the denitrosylation of RSNO (Fig. 1).2b Further, {111} facets may be employed for a quick release of NO, whereas the {011} facets will be useful for a slow and sustained release of NO. Therefore, the facet- dependent denitrosylation activity may find potential applications in modulating the NO bioavailability under disease conditions such as endothelial dyfunction in which the physiological NO signaling is severely impaired.

Figure 1. Denitroisylation of RSNO and detection of nitric oxide. References: 1. Moncada, S.; Palmer, R. M.; Higgs, E. A. Pharmacol. Rev. 1991, 43, 109-142; b) The Nobel Prize in Physiology or Medicine 1998. Nobelprize.org; c) Melino, G.; Bernassola, F.; Knight, R. A.; Corasaniti, M. T.; Nistic, G.; Finazzi-Agro, A. Nature 1997, 388, 432-433; 2. Wang, P. G.; Xian, M.; Tang, X.; Wu; X.; Wen, Z.; Cai, T.; Jaczuk, J. A. Chem. Rev. 2002, 102, 1091-1134; b) Ghosh, S.; Roy, P.; Prasad, S.; Mugesh, G. Chem. Sci. 2019, 10, 5308- 5318.

175

P84: Nanoceria-Based Cell Membrane Disruptive Phospholipase-Mimetic Nanozymes

Kritika Khulbe, Govindasamy Mugesh*

Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore

Antimicrobial resistance (AMR) has abrogated the initial phase of chemotherapeutic effects of antimicrobial drugs propounded by the Nobel Prize winning discovery of penicillin by Sir Alexander Fleming, Ernst Boris Chain and Sir Howard Walter Florey.[1a] Surprisingly, gram-positive bacteria have in-built cell death mechanism using ribosomally-synthesized bactericidal peptides, “lantipeptides” which are responsible for disruption of the cell membrane integrity by formation of pores on the surface or inhibition of cell wall synthesis ultimately leading to apoptosis. However, analogous antibiotic effect in gram-negative bacteria is not known due to the inability of lantipeptides to cross the outer cell membrane barrier.[1b-c] Thus, a material capable of traversing the outer membrane of gram- negative bacteria would have potential antibacterial activity on a wide range of bacteria.Among the [2a] new approaches, the redox active catalytic activity of CeO2 has gained attention. In this study, we used a nanomaterial functionalization-based strategy using coated cerium oxide-based nanoparticles for the targeting and disruption of bacterial cell membrane. We describe for the first time the cell membrane degradation ability of a remarkable phospholipase-like active ceria nanozyme (Figure 1). The dual oxidation state (Ce3+ and Ce4+) surface provide catalytic site for binding and hydrolysis of long-chain phospholipids present on the bacterial cell membrane, whereas the polymer coating provided sufficient dispersibility to the nanostructure for enhanced antibacterial activity. The phospholipase activity of our coated nanozyme has enhanced bactericidal effect on a broad range of planktonic and biofilm bacteria.[2b] Broad-spectrum phospholipase mimetic of the nanozyme has potential application for preventing bacterial colonization and biofilm formation on the surface of urinary catheters, a major cause of the health care-associated urinary tract infections

Figure1:

References:

1. a) Alekshun, M. N.; Levy, S. B. Molecular Mechanisms of Antibacterial Multidrug Resistance. Cell 2007, 128, 1037-1050; b) Knerr, P. J.; van der Donk, W. A. Discovery, Biosynthesis, and Engineering of Lantipeptides. Annu. Rev. Biochem. 2012, 81, 479–505; c) Li, Q.; Lopez, M. M.; Kuipers, O. P. Increasing the Antimicrobial Activity of Nisin-Based Lantibiotics against Gram-Negative Pathogens. Appl. Environ. Microbiol. 2018, 84, e00052-18. 2. a) Xu, C.; Qu, X. G.; Cerium Oxide Nanoparticle: A Remarkably Versatile Rare Earth Nanomaterial for Biological Applications. NPG Asia Mater. 2014, 6, e90; b) Manuscript submitted.

176

P85: One-pot synthesis of novel Ru(II)-p-cymene-2-aryl benzimidazole (BIZ), benzothiazole (BTZ) and benzoxazole (BOZ) scaffolds: the influence of regioisomer on cytotoxicity and reactivity towards DNA and protein

Ashaparna Mondala, Utsav Senb, Nilmadhab Roya, Priyankar Paira*a, Bipasha Boseb aDepartment of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore- 632014, Tamil Nadu, India bStem cells and Regenerative Medicine Centre, Yenepoya University, Mangalore, Karnataka, India

During last few decades researchers came up with a lot of advancement in diagnosis and treatment of cancer. Herein, a one-pot protocol was adopted to synthesize Ru(II)-arene 2-aryl benzimidazole/ benzothiazole/ benzoxazole complexes under continuous sonication. A series of Ruthenium arene complexes are reported for anticancer screening in terms of cytotoxicity and selectivity against cancer cell lines. The regioisomers of these complexes are also isolated by preparative thin layer chromatography and their stability was well supported by DFT calculation. [(η6-p-cymene)Ru-2-(5, 6- dichloro-1H-benzo[d]imidazole-2-yl)quinoline] (11j) was found to be significantly potent and selective in Caco-2, Hela cell line respectively compared to cisplatin. These types of Ru(II)-arene complexes exhibited effective intercalation binding with DNA. Since, [(η6-p-cymene)Ru-2-(6-nitro-1H- benzo[d]imidazole-2-yl)quinoline] (11f´) was identified as good fluorescent as well as potent scaffold it can be a developed as good drug candidate for cancer theranostics. Complex 11j was further tested against more invasive cancer cell line- Ht-29 (colon cancer cell line) to understand the mechanism of cancer cell apoptosis.

Figure: Design of Ru(II)-η6-p-cymene benzimidazole (BIZ), benzothiazole (BTZ) and benzoxazole (BOZ) scaffolds and cell apoptosis mechanism.

References:

1. C. G. Hartinger, S. Zorbas-Seifried, M. A. Jakupec, B. Kynast, H. Zorbas and B. K. Keppler, J. Inorg. Biochem., 2006, 100, 891. 2. N. P. Barry and P. J. Sadler, Chem. Commun., 2013, 49, 5106. 3. S. B. Lara, L. Salassa, A. Habtemariam, O. Novakova, A. M. Pizarro, G. J. Clarkson, B. Liskova, V. Brabec and P. J. Sadler, Organometallics, 2012, 31, 3466. 4. S. K. Subran, S. Banerjee, A. Mondal and P. Paira, New J. Chem., 2016, 40, 10333.

177

P86: Utility of 2-Amino pyridine: A hit to lead identification study

Nishanth.R, Kaushik Chanda*

Department of Chemistry, Vellore Institute of Technology, Vellore-632014, India.

2-aminopyridine is a classic example of key core structure, used to graft with other complex groups in achieving potent pharmacophores with broad spectrum biological importance. It contributes to valuable part of marketed drugs such as Piroxicam (Anti-inflammatory), Sulfapyridine (Antibacterial) Tripelennamine (Anti histaminic), Delavirdine (Anti-HIV) etc. Research in pharmaceutical industry is nowadays eyeing on discovery of small heterocycles as these form less number of metabolites invivo and also eradicate the chances of toxicity due to multiple bulkier groups2.In this context we developed an expeditious catalyst-free heteroannulation reaction in green solvent under microwave irradiation starting from 2-aminopyridine to access imidazo[1,2-a]pyridines/ pyrimidines/ pyrazines and evaluated their antimicrobial and anti-inflammatory activity3. Screening results uncovered three derivatives with strong inhibition of albumin denaturation and two derivatives were active on Proteus and Klebsiella bacteria. To further evaluate utility of 2-aminopyridine we developed a synthetic strategy to accomplish thizolidine-2-imines by reacting 2- aminopyridines/pyrimidines and pyrazines with substituted isothiocyanates

References:

1. Bolliger, J.L.; Oberholzer, M.; Frech,C.M. Advanced Synthesis & Catalysis. 2011, 353, 945. 2. Nakamura, I.; Yamamoto, Y. Chem. Rev., 2004, 104, 2127. 3. Nishanth, R.; Balamurali,M.M.; Maiti,B.; Thakuria,M.; Chanda, K. ACS Comb. Sci. 2018, 20,164.

178

P87: Computational Studies of Selective N-methylation of Nicotinamide as an Epigenetic Mechanism in Cancer

Masthan Thamim, Krishnan Thirumoorthy*

Department of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore- 632014, Tamil Nadu, India

The selective N-methylation reaction of nicotinamide by Nicotinamide N-methyltransferase (NNMT) in the biological nanospace is being considered as one of the most common epigenetic changes in biology1. The methylation in biology is the fundamental biotransformation reaction which alters the structure and function of the biomolecules. The changes in methylation potential in biochemical reaction lead to hyper- and hypomethylation thus it triggers the cancer cell signaling2. The NNMT catalyzes the N-methylation of nicotinamide using S-adenosyl-L-methionine to produce 1- Methylnicotinamide (1-MNA) instead of 7-Methylnicotinamide (7-MNA) remains unexplored though inspiring 7-MNA similar kinds reported with Glycine N-methyltransferase in prostate cancer3. In this direction, the present work aims to address mechanistic aspects of selective N-methylation of NA in the active site of NNMT using computational quantum chemical calculations. As a result, the formation of 1-MNA shows thermodynamic and kinetic stabilities as compared to 7-MNA. The 1-MNA formation alters the methylation genomic pattern which triggers the activation of oncogenic signaling pathway.

References:

1. Aksoy, S.; Szumlanski, C. L.; Weinshilboum, R. M. Human Liver Nicotinamide N- Methyltransferase. CDNA Cloning, Expression, and Biochemical Characterization. J. Biol. Chem. 1994, 269 (20), 14835–14840. 2. Ulanovskaya, O. A.; Zuhl, A. M.; Cravatt, B. F. NNMT Promotes Epigenetic Remodeling in Cancer by Creating a Metabolic Methylation Sink. Nat Chem Biol. 2013, 9. https://doi.org/10.1038/nchembio.1204. 3. Sreekumar, A.; Poisson, L. M.; Rajendiran, T. M.; Khan, A. P.; Cao, Q.; Yu, J.; Laxman, B.; Mehra, R.; Lonigro, R. J.; Li, Y.; et al. Metabolomic Profiles Delineate Potential Role for Sarcosine in Prostate Cancer Progression. Nature 2009. https://doi.org/10.1038/nature07762.

179

P88: Development of New Coumarin Hydrozone as Fluorogenic Chemosensor for Lu3+ ion Determination

Mujthaba Aatif A, S.K. Ashok Kumar*

Department of Chemistry,School of Advanced Sciences, Vellore Institute of Technology, Vellore- 632014. Tamil Nadu, India.

A new coumarin hydrozone Ligand (L) has been synthesized for the selective determination of Lu3+ by spectrofluorometric technique. The ligand L exhibits an emission band at 490 nm upon excitation at 437nm. The ligand L, upon interaction with Lu3+ the emission band increased with a five-fold enhancement at 490 nm in DMSO: water (7:3, v/v) media. The formation of host-guest complexation between L and Lu3+ found to be 2:1 confirmed by Job's and the binding constant (Ka = 1.43 ×104 M-2) was estimated by the Benesi-Hildebrand method. The ligand L could work in the pH range from 2.0 to 5.0 without interfering form other interfering ions. The limit of detection of L was found to be 70 nM. Further, the binding mechanism of L with Lu3+ was supported by 1H-NMR, FT-IR and ESI mass spectral studies and experimental results were well supported with theoretical studies.

References:

1. R. Selva Kumar, S.K. Ashok Kumar, Kari Vijayakrishna, Akell Sivaramakrishna, C.V.S. Brahmnanda Rao, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 214 (2019) 32. 2. Lina Wang, Juanjuan Tang, Ning Sui, Xing Yang, Luyao Zhang, Xiaojun Yao, Qinfei Zhou, Hailian Xiao, Shaoping Kuang and William W. Yu, Anal. Methods, 2017, 9, 6254. 3. F. Faridbod, M. Sedaghat, M. Hosseini, M.R. Ganjali, M. Khoobi, A. Shafiee, P. Norouzi, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 137 (2015) 1231. 4. Morteza Hosseini, Mohammad Reza Ganjali, Zahra Rafiei-Sarmazdeh, Farnoush Faridbod, Hassan Goldooz, Alireza Badiei, Parviz Nourozi, Ghodsi Mohammadi Ziarani, Analytica Chimica Acta 771 (2013) 95.

180

P89: Development of Fluorescein Based Ruthenium (II) Complex for Cytotoxicity and Antibacterial Applications

S. Pravinkumara,b, S. K. Ashok Kumara*, I. Pradeepb*

aDepartment of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore- 632014 bDepartment of chemistry, Bishop Heber College (Autonomous), Tiruchirappalli-620017.

A new fluorescein-based ruthenium (II) complex was synthesized and characterized by various spectroscopic techniques. The light absorbing and emission property of Ru(II) complex were studied by using spectrophotometry and spectrofluorimetric methods. The results reveal that the complex shows two major absorption peaks were appeared 300 nm and 420 nm which is due to the π-π* transitions and metal to ligand charge transfer (MLCT) respectively. Its shows the emission peak appeared at 530 nm upon the excitation at 420 nm. Further, biological studies such as cytotoxicity and antibacterial activity were performed and results reveals that Ru(II) complex exhibits higher activity against Proteus vulgaris bacteria. Further, it shows a potency and cytoselectivity in lung cancer cell line [A549] with the IC50 concentration of 9.74 µM. Hence, this Ru(II) complex was found to be useful for cytotoxicity and antibacterial agent.

Fluorescein Ruthenium Antibacterial Cytotoxicity complex Study Study

References:

1. I.Pradeep, B.Balajothi, S.Arunachalam, R.Dhivya, A. Vinothkanna, M.Abdulkadher Akbarshab and S. Sekar RSC Adv., 2016, 6, 318 2. C.F. Ramogida and C. Orvig, “Chem. Commun. (Cambridge, U. K.), 2013. 49: p. 4720 3. N.Jadeja, K.M.Vyas, K.K.Upadhyay, R.V.Devkar. RSC Adv., 2017, 7, 17107.

181

P90: Design and synthesis of visible organic light-emitting materials

Leyana K Shaji, Ashok Kumar S.K*.

Department of Chemistry, School of Advanced Sciences.Vellore Institute of Technology, Vellore - 632014.

In this work, a new Schiff‟s base (S) synthesised and characterised as new class of solid-state emissive organic fluorophore by reacting 2-amino-benzo-isoquinoline-1,3-dione with para-substituted aldehyde leads under simple reaction conditions. Results show that on excitation of S at 380 nm in the solid state, it exhibits a new emissive peak at 585 nm with stokes shift of 205 nm while in the solution phase very weak emissive power. The high solid state emissive is due perfect π-π stacking in the system while in solution phase this structure get destroyed which leads to less emission. The observed photo physical properties were supported by DFT/TDDFT calculations in both solid phase. All these preliminary results indicated that S can act as quite promising light-emitting materials for OLED applications.

Figure: Absorbance and emission spectral response of S in solid state.

References:

1. Bera, M. K.; Chakraborty, C.; Malik, S. J. Mater. Chem. C 2017, 5, 6872. 2. Malina, I.; Kampars, V.; Turovska, B.; Belyakov, S. Dye. Pigment. 2017, 139, 820. 3. Dhar, J.; Venkatramaiah, N.; Anitha, A.; Patil, S. J. Mater. Chem. C 2014, 2, 3457. 4. Tagare, J.; Vaidyanathan, S. J. Mater. Chem. C 2018, 6, 10138.

182

P91: Synthesis and Characterisation of Substituted 2-oxo-4H-chromen-3-acrylonitrile Derivatives for Optoelectronic Applications

Suman Josph, Selva Kumar R, S.K. Ashok Kumar*

Department of Chemistry,School of Advanced Sciences, Vellore Institute of Technology, Vellore - 632014.

In this work, we have design and synthesized new 2-oxo-4H-chromen-3-acrylonitrile derivatives (4a- 4j) using multicomponent one pot synthesis. All synthesised derivatives are characterised by various spectroscopy and mass analysis. The emission study of 4e, 4i, and 4j in solid state and 4b, 4e, 4g and 4h in solution phase exhibits high emission characteristics. The solvatochromism study shows that all compounds are having positive solvatochromism nature. The derivatives 4b, 4g and 4h shows good AIE and rest of the derivatives follow ACQ properties. The TDG/DSC study shows that the compound having high thermal stability. Besides, the observed photophysical properties are correlated with theoretical calculation.

References:

1. R. Sébastien, E. Gwenaëlle, I. Martin, et al., Dyes and Pigments, 2018, 156:116. 2. B. Umamahesh, M. Saravanakumar, D.T. Manojkumar, et al. RSC Adv., 2016, 6, 58549. 3. W. Bentoumi, J. C. Mulatier, P. A. Bouit, et al., Chem. Eur. J., 2014, 20, 8909.

183

P92: One-Pot Multi-component Biginelli Reaction Catalyzed by Ionic Liquid Immobilized Proline(s) Organocatalyst

Prabhakara M D, Barnali Maiti*

Department of Chemistry, School of Advanced Science, Vellore Institute of Technology,Vellore- 632014, Tamil Nadu, India.

A highly efficient synthetic methodology has been developed for one-pot synthesis of 3,4- dihydropyrimidin-2-(1H)-ones catalyzed by ionic liquid immobilized proline(s) organocatalyst at room temperature in IPA solvent. Three components such as aryl aldehydes, β-ketoesters and urea in one- pot underwent Biginelli reaction using 5 mol% ionic liquid immobilized proline(s) organocatalyst at room temperature. This method offers several advantages such as low catalyst loading percentage, short-reaction times, mild reaction conditions, excellent yields, chromatography-free, and metal-free synthesis. The organocatalyst could be recycled and reused five times without significant loss of catalytic activity. The final product was characterized by 1H NMR, 13C NMR, Mass and IR spectra analysis.

Scheme 1: Multi-component Biginelli Reaction catalyzed by ionic liquid-immobilized proline(s) organocatalyst.

References:

1. Prabhakara, M. D.; Maiti, B. Res. Chem. Inter. 2020, (in press).

184

P93: Ramification of donor-acceptor alternation to analyse emission behaviour of V-shaped thiophene donor and thiazole acceptor towards aggregation pathway

P. S. Umabharathi and S. Karpagam*

Department of Chemistry, School of Advanced Science, VIT University,Vellore -14. Tamil Nadu, India

A novel series of D-π-A-π-D configured conjugated oligomer with V type structure were efficiently synthesized by Wittig condensation reaction. Thiophene and thiazole type of donor-acceptor based series of conjugated oligomer, Oligo-4,4'-benzothiazole-5,6-diylbis (ethane-2,1-diyl)bis (thiophene-5,2- diyl)bis (N, N-diphenyl aniline) were synthesized. This core moiety exclusively selected to increase the planarity, rigidity, stability and extend the π–conjugation. D-π-A-π-D configured conjugated oligomer were analysed from FT-IR, NMR technique and optical properties were done by UV-visible (optical absorption). The photo luminescence spectrum of the oligomer was observed. By increasing the water: THF fraction, switching of different emission colour, observed different emission wavelength and particle was aggregated which was examined from PL spectroscopy.

Scheme: Synthesis of D-π-A-π-D configured conjugated oligomer with V-type structure.

References:

1. Kakekochi, V.; Chandrasekharan, K.; Kumar, U Dyes and Pigments. 2020, 3, 108181. 2. Jagadeesan, S.; Mahesh, K.; Karpagam, S.ChemistrySelect. 2019, 4(37), 11196-205.

185

P94: A Robust and Recyclable Ionic liquid Supported Copper (II) Catalyst for the Synthesis of 5-Substituted-1H-tetrazoles using Microwave Irradiation

R D Padmaja and Kaushik Chanda*

Department of Chemistry,School of Advanced Sciences, Vellore Institute of Technology, Vellore.

A novel and robust ionic liquid supported copper (II) catalyst has been developed and explored for the efficient synthesis of 5-substituted-1H-tetrazoles using microwave irradiation. The use of ionic liquid supported catalyst facilitated for the efficient isolation of the tetrazole products by simple extraction with organic solvent with high purity. Recovered ionic liquid supported copper (II) catalyst could be recycled for three times for the synthesis of tetrazole products with high purity. This synthetic protocol offers a very clean, convenient, and microwave assisted environment friendly method for the efficient synthesis of 5-Substituted-1H-tetrazoles with high yield.

References:

1. Amantini, D.; Beleggia, R.; Fringuelli, F.; Pizzo, F.; Vaccaro, L. J. Org. Chem., 2004, 69, 2896. 2. Jiun-Jie Shie and Jim-Min Fang* ; J. Org. Chem. 2007, 72, 3141 3. Maiti, B.; Chanda, K. RSC Adv., 2016, 6, 50384. 4. Padmaja, RD.; Rej, S.; Chanda, K. Chin. J. Catal., 2017, 38, 1918.

186

P95: Cyclometalated Ir(III) Complexes as Probes for DNA Mismatches and Abasic Sites

P. David Dayanidhi, and V.G. Vaidyanathan*

Advanced Materials Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600 020.

Damage to our genetic material occur very often from various sources. Formation of DNA defects is the initial step in tumor growth. Among various defects, the formation of thermodynamically unstable sites such as mismatches and abasic sites are of great importance as failure in repair of these defects results in mutagenesis. While errors during DNA replication give rise to mismatch base pairing, cleavage of glycosidic bond by hydrolysis between a nitrogenous base and a 2‟-deoxyribose due to exposure to UV radiation and other sources leads to the formation of abasic sites.1,2 Design of molecules that target specific defects in DNA is of prime importance in order to prevent mutations. It is found that metal-complexes can selectively recognize these defects by insertion of the planar ligand + into the defected site. Here, we present three Ir(III) complexes, [Ir(ppy)2(imiphen)] (1), + + [Ir(ppy)2(furphen)] (2), and [Ir(ppy)2(faqphen)] (3), where 1 selectively recognizes Ab:T and CA mismatch, 2 recognizes Ab:G and 3 recognizes TT mismatch.

+ Fig: a) Structures of [Ir(ppy)2(L)] ; b) DNA sequences used in this study

References:

1. Dahlmann, H. A.; Vaidyanathan, V. G.; Sturla, S. J. Biochemistry 2009, 48 (40), 9347. https://doi.org/10.1021/bi901059k. 2. Boynton, A. N.; Marcélis, L.; Barton, J. K. [Ru(Me4phen)2dppz]2+, a Light Switch for DNA Mismatches. J. Am. Chem. Soc. 2016, 138 (15), 5020. https://doi.org/10.1021/jacs.6b02022.

187

P96: An Efficient, Heterogeneous Cu(I)-SBA Catalyzed One Pot Synthesis of 3,4- Dihydropyrimidin-2(1H)-Ones

M. Thennila1,2, S. Muthumanickam1, M. Sivabharathy2, K. Selvakumar1*

1 Research Department of Chemistry, Thiagarajar College, Madurai, Tamil Nadu, 625 009, India 2 Department of Physics, Sethu Institute of Technology, Kariapatti, Tamil Nadu, 626 115, India

The catalytic application of Cu(I) incorporated ordered mesoporous silica SBA-15 (Cu(I)-SBA-15) has been evaluated for one‐pot Biginelli reaction for synthesizing 3,4-dihydropyrimidine-2-(1H)-ones. The 3,4-Dihydropyrimidin-2(1H)-One (DHPM) unit is present in various biologically active molecules and its derivatives exhibit a wide range of pharmacological properties such as antiviral, antimitotic, anticarcinogenic, antihypertensive etc. The catalyst was prepared first time by alcothermal strategy using P-123 as surfactant. The morphology and porosity of the catalyst were then characterized by SEM, TEM, SAXS, XRD and BET analysis. The performance of the Cu(I)-SBA-15 catalyst was investigated in the Biginelli reaction with variety of halide/phenyl substituted aldehydes, alkylacetoacetates and urea/thiourea under room temperature conditions. The catalyst exhibited excellent activity provided corresponding Biginelli products in good to excellent yields. The reactivity, reusability and stability of the catalyst were also investigated under the optimum reaction conditions .

Scheme 1: Biginelli reaction using Cu(I)-SBA catalyst.

Reference:

1. Zhu, Y.; Huang, S.; Wan, J.; Yan, L.; Pan, Y.; Wu, A, Org. Lett. 2006, 8, 12, 2599. 2. Chandak, H. S.; Lad, N. P.; Upare , P. P. Catalysis Letters, 2009, 131, 469. 3. Dharma Rao, G.B.; B. Anjaneyulu, Kaushik, M. P., RSC Adv., 2014, 4, 43321.

188

P97: Development of Acrylonitrile-based Turn-on Fluorescence Chemosensor for Cyanide ion Determination

Pranati Somkuwar, Shital Mohurle, and Ashok Kumar S.K*

Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore.

A new acrylonitrile-based turn-on fluorescence chemosensor (L) was developed by reacting 9-ethyl- 9H carbazole-3-carbaldehyde with 2-(benzo[d]thiazol-2-yl) acetonitrile. The sensing ability of receptor L was studied by using colorimetric, spectrophotometric and spectrofluorimetric methods. The ligand L shows highest selectivity towards CN- ions in terms of turn-on fluorescence response at 475 nm upon the excitation at 350 nm. The fluorescence spectral study reveals that the formation of 1:1 stoichiometry complex between L and CN- with an estimated association constant of 2.04 ×105 M-1 by chemodosimetric mechanism. The L could detect CN- ions down to 1.48 nm without interfering from other common interfering ions. Further, the binding mechanism of L was studied by using 1H NMR, ESI-Mass and theoretical studies.

References:

1. Y. K. Yue, F. J. Huo, C. X. Yin, J. B. Chao and Y. B. Zhang, Sens. Actuators, B, 2015, 212, 451. 2. S. S. Razi, R. Ali, P. Srivastava and A. Misra, Tetrahedron Lett., 2014, 55, 1052 3. B. Vennesland, E.E. Comm, C.J. Knownles, J. Westly, F. Wissing, Cyanide in Biology, Academic Press, London, 1981. 4. R. Takano, The treatment of leprosy with cyanocuprol, J. Exp. Med. 24 (1916)207–211.

189

P98: Bioinorganic Chemistry of Co(II) and Mn(II) complexes

V.K. Srivastava

Department of Chemistry D.S. College, Aligarh UP (India)

Schiff bases containing penicillin and heterocyclic structural units with N,N, donor atoms are considered the most prominent research area in the field of coordination chemistry [1-6]. The various donor atoms in them offer special ability for binding metals. Schiff base change the physiological, morphological and Pharmacological activities of the compounds. Schiff base complexes have been used as drugs and have valuable antibacterial antifungal, anti- inflammatory and antitumor activities. A large number of Schiff bases and their complexes have been studied for their interesting and important properties e.g. their ability to reversibly bind oxygen, catalytic activity in hydrogenation of olefins and transfer of an amino group photochromic properties. The high affinity for the chelation of the Schiff bases towards the transition metal ions is utilized in preparing their solid complexes. In the present paper the Co(II) and Mn(II) complexes were synthesized with Schiff base ligand 2- Thio phenyl glyoxal anthranilicacid (TGAA). The coordination behavior of the ligand towards transition metal irons was fully investigated by various spectral techniques. Biochemical Behavior of the complexes were evaluated by antimicrobial, Enzyme inhibition activity and cytotoxic studies.

190

P99: Redox Switching of First Hyperpolarizability of Ru Based Metal Complexes

Karthika, C.1, P. K. Das 1

1Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India

Organotransition metal complexes are promising in the field of molecular switches and opto-electronic devices due to their structural stability in two different oxidation states and large second harmonic response. Metal complexes with different second harmonic responses in different states have been considered for data storage applications. Tuning of second harmonic response or the molecular level property, β, electrochemical switching gained maximum attention due to minimum structural relaxation caused by direct oxidation/reduction of the metal centre. Here we report two Ru based bimetallic 1 complexes, [NC-Ru-(bpy)2-CN-Ru(bpy)2-CN](PF6) (1) and [Ru(bpy)2-bptz-Ru(bpy)2](PF6)2 (2) and investigated their second harmonic generation after sequential oxidation/reduction of the Ru centre(s) electrochemically. We have determined from cyclic voltammetry (CV) that the first oxidation of 10 to 1+1 occurs at +0.75 V and the second oxidation1+1 to 1+2 at +1.34 V. Similarly, the CV of the 2 complex shows that the first oxidation of 20 to 2+1occurs at a much higher potential of + 1.95 V and the second oxidation to 2+2 at +2.2 V. The spectro-electrochemical studies suggest that the mixed-valent (MV) state of both the complexes exhibit an IVCT band in the infrared around ~1200 nm, which is assigned to the metal-metal charge transfer from Ru (II) to Ru(III) states. In-situ second harmonic light scattering (SHLS) experiments were carried out in a customized electrochemical cell, where the SH intensity was measured with respect to a particular oxidation state.2 The MV state possess 3 times higher β value compared to the other states of the complexes, which are perhaps due to resonance enhancements mediated by the IVCT band at the incident wavelength (1064 nm) and the MLCT band at SH wavelength (532 nm).

Figure 1: Structure of complex 1 and 2

References: 1. Bignozzi, C. A.; Roffia, S.; Chiorboli, C.; Davila, J.; Indelli, M. T.; Scandola, F. Inorg. Chem.1989, 28 (24), 4350–4358. 2. Karthika, C.; Sarath Kumar, S. R.; Kathuria, L.; Das, P. K.; Samuelson, A. G.. Phys. Chem. Chem. Phys.2019, 21 (21), 11079–11086.

191

P100: Development Of Novel Ru(II), Ir(III) and Ru(II)-Ir(III) Mix metal Complexes and their cancer theranostics application

Prithivi Moharana,. Priyankar Paira

Department of Chemistry (SAS), Vellore Institute Of Technology,Vellore-14, India

The perilous impact of cancer is now a matter of great frightening to us after the heart disease. Although the discovery of platinum based drug, cisplatin initiated the use of metallodrug in cancer therapy but its several drawbacks are diminishing its use nowadays. While, ruthenium and iridium based drugs are now being exploited as better substitute of cisplatin due to their good cytoselectivity, target specificity, aqueous solubility, and good fluorescent property. Therefore presence of ruthenium and iridium metals together in a same moiety reinforce the drug to be more selective and useful in invivo imaging giving fluorescent emission at NIR region. Embroidered polynuclear transition metal based heterodimetallic complexes with appropriate ligand framework often combine properties of individual metals into the same unit and allow cooperative interaction which leads to enhanced properties and biological activities as compared to their monometallic counterparts.

References:

1. Lobo, N. A.; Shimono, Y.; Qian, D.; Clarke, M. F.; Annu. Rev. Cell Dev. Biol., 2007, 23, 675

192

P101: Polyvinylidene Fluoride/Aliphatic Hyperbranched Polyester (Generation-3) Electrospun Nanoweb based Piezoelectric Sensors

Priyanka Yadava,P.Lakshmi prabaa, R. Gunasekhara, B. Indumathy, M.S. Rezab, Hongdoo Kimb,**, A. Anand Prabua,* aDepartment of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India bDepartment of Advanced Materials Engineering for Information & Electronics, Kyung Hee University, Gyeonggi-do 17104, Korea

In the present study, aliphatic hyperbranched polyester of 3rd generation (Al-HBP-G3) was synthesized using pentaerythritol (PE) as core and dimethylol propionic acid (DMPA) as aliphatic o monomer by one-shot melt-polycondensation method (140 C, 20 h, N2 atm.). Though the synthesis methodology is already reported [1], we studied the effect of reduced pressure at regular intervals on the Al-HBP-G3 reaction kinetics, which is unreported so far. Samples collected at regular intervals of time were analysed using FT-IR, NMR (H1 & C13) and thermal analyses (DSC, TGA) for optimizing the reaction conditions and for understanding the structural changes during HBP formation as a function of reaction time. Further, electrospinning was done with neat PVDF and its blends with Al-HBP-G3 (0, 10, 20, 30 and 40 wt.% of HBP w.r.t. PVDF) under controlled electrospinning conditions. The nanoweb samples were analysed using FT-IR and XRD, which showed increasing β-crystallinity in PVDF with increasing HBP content which is an evidence that piezoelectric sensors with higher output voltage can be possibly achieved using PVDF/HBP blends than that achieved using neat PVDF. Piezoelectric sensors fabricated using the nanoweb samples were subjected to dynamic pressure (1 kgf, 1.0 Hz) condition and their piezoelectric output signals were analysed to optimize the PVDF/HBP content under the measured conditions [2,3].

References:

1. D.M. Dhevi, A.A. Prabu, H. Kim, M. Pathak, J. Polym. Res., 21(7), 1-9 (2014). 2. P. Sathiyanathan, A.A. Prabu, K.J. Kim, Macromol. Res., 24, 670-674 (2016). 3. G. Prasad, P. Sathiyanathan, A.A. Prabu, K.J. Kim, Macromol. Res., 25, 981-988 (2017).

193

P102: Polyvinylidene Fluoride/Aliphatic Hyperbranched Polyester (Generation-1) Electrospun Nanoweb based Piezoelectric Sensors

P. Lakshmi Prabaa, Priyanka Yadava, R. Gunasekhara, B. Indumathy, M.S. Rezab, Hongdoo Kimb,**, A. Anand Prabua,* aDepartment of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India bDepartment of Advanced Materials Engineering for Information & Electronics, Kyung Hee University, Gyeonggi-do 17104, Korea

In the present study, aliphatic hyperbranched polyester of 1st generation (Al-HBP-G1) was synthesized using pentaerythritol (PE) as core and dimethylol propionic acid (DMPA) as aliphatic o monomer by one-shot melt-polycondensation method (140 C, 20 h, N2 atm.). Though the synthesis methodology is already reported [1], we studied the effect of reduced pressure at regular intervals on the Al-HBP-G1 reaction kinetics, which is unreported so far. Samples collected at regular intervals of time were analysed using FT-IR, NMR (H1 & C13) and thermal analyses (DSC, TGA) for optimizing the reaction conditions and for understanding the structural changes during HBP formation as a function of reaction time. Further, electrospinning was done with neat PVDF and its blends with Al-HBP-G1 (0, 10, 20, 30 and 40 wt.% of HBP w.r.t. PVDF) under controlled electrospinning conditions. The nanoweb samples were analysed using FT-IR and XRD, which showed increasing β-crystallinity in PVDF with increasing HBP content which is an evidence that piezoelectric sensors with higher output voltage can be possibly achieved using PVDF/HBP blends than that achieved using neat PVDF. Piezoelectric sensors fabricated using the nanoweb samples were subjected to dynamic pressure (1 kgf, 1.0 Hz) condition and their piezoelectric output signals were analysed to optimize the PVDF/HBP content under the measured conditions [2,3].

References

194

P103: Stabilization of collagen using amine functionalized TiO2 nanoparticles

S. Nagaraj, P. Thanikaivelan*

Advanced materials laboratory CSIR-Central Leather Research Institute, Adyar, Chennai 600020

Crosslinking proteins such as collagen using physical and chemical methods offers an enhanced thermal stability and mechanical properties.1 Being a biomolecule, adopting nanotechnology for crosslinking the collagen would provide additional advantages in realizing its usage in the perspective of both biomedical and industrial application.2 In this work, we report a method to stabilize collagen fibres by using 3-aminopropyltriethoxysilane (APTES) functionalized TiO2 nanoparticles via a method utilizing N-hydroxysuccinimide (NHS) and 1‐ethyl‐3‐(dimethylaminopropyl)carbodi‐imide (EDC). NHS and EDC together activate the carboxylic acid groups of collagen to give O-acylisourea groups, which will react with terminal amino groups of APTES functionalized TiO2 nanoparticles. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and 13C-nuclear magnetic resonance spectra 13 ( C-NMR) were the characterization techniques carried out for TiO2 and APTES functionalized TiO2 nanoparticles. APTES functionalized TiO2 nanoparticle crosslinking increases the hydrothermal stability of collagen measured by using differential scanning calorimetry (DSC) ⁓ 85 °C suggesting that functionalized nanoparticle is able to improve thermal stability of collagen fibres. Circular dichroism and FT-IR spectra revealed that there is no alteration in the secondary structure of collagen fibers on the treatment with functionalized nanoparticles. Hence, we propose the use of APTES functionalized TiO2 nanoparticles for the effective crosslinking of collagen fibres.

References:

1. Ma, L.; Gao, C.; Mao, Z.; Zhou, J.; Shen, J., Biomaterials 2004, 25 (15), 2997-3004. 2. Nagaraj, S.; Easwaramoorthi, S.; Rao, J. R.; Thanikaivelan, P., International journal of biological macromolecules 2019, 131, 779-786.

195

P104: Di- and Trinuclear Pt(II) Complexes of Pyridinyl Benzimidazole Ligands as Anticancer Agents: Effect of Nuclearity and Ancillary Ligands

N. U. Prajith and V. Alexander*

Department of Chemistry, Loyola College, Chennai 600034, India

The lipophilicity and anticancer activity of the dinuclear platinum(II) complexes [(Am-py)2Pt--(L1)-

Pt(Am-py)2](ClO4)4 (1) and [(HO-py)2Pt--(L1)-Pt(HO-py)2](ClO4)4 (2) and the trinuclear complexes

[((Am-py)2Pt)3-3-(L2)](ClO4)6 (3) and [((HO-py)2Pt)3-3-(L2)](ClO4)6 (4) of the pyridinyl benzimidazole ligands L1 and L2 and their dependence on the nature of ancillary ligands and nuclearity are reported. The complexes 2 and 4 containing 3-hydroxypyridine are more hydrophilic than 1 and

3 containing 4-aminopyridine ancillary ligand and the logPo/w value decreases with increase in nuclearity. The dinuclear complexes 1 and 2 demonstrate higher cytotoxicity (IC50 values 24–29 and 29–34 M, respectively) on the HeLa, MCF-7, and HepG2 cell lines than the trinuclear complexes 3 and 4 (IC50 values 39–48 and 46–58 M, respectively). The IC50 values of the complexes 1-4 on Vero cell line are 47, 51, 65, and 72 M, respectively. The complexes induce cell cycle arrest in the G0/G1 phase. The ethidium bromide/acridine orange dual staining assay indicates both apoptotic and necrotic cell death while annexin V-alexa fluor 488/propidium iodide apoptosis assay shows necrotic pathway of cell death. The dinuclear complexes 1 and 2 trigger necrosis at lower concentration, while at higher doses apoptotic mode of cell death is observed. The trinuclear complexes 3 and 4 prompt necrotic mode of cell death in a dose dependent manner.

Cytotoxicity EB/AO dual staining assay 1 2 3 4

Annexin V-Alexa fluor488/PI Assay

196

P105: Phase Formation and in-Vitro bioactivity evaluations of Zinc and Silver co-substituted Strontium Phosphosilicate composites for Orthopaedic applications

Chetan, U. Vijayalakshmi*

Department of Chemistry, School of Advanced Sciences,Vellore Institute of Technology, Vellore, Tamil Nadu, INDIA.

The exploitation of structural biocompatible features of apatite coupled with antibacterial properties of inorganic dopants forms basis of the study.[1] Synthesis of Zinc and Silver co-substituted Strontium phosphosilicate was attempted in a low pH acidic medium with an equal concentration of dopants increasing hierarchically for structural and Biological evaluations. Aqueous Sol-Gel technique ensured proper reactivity in the reaction mixture.[2] The acidic medium was found to be more applicable on account of the isoelectric point of silica leading to formation of secondary Sr2SiO4 phase apart from

Sr2P2O7. Sintering formed stable crystalline phases evident from diffraction data showing very little change in spectra confirming proper incorporation of dopants at respective lattice sites. Infrared spectroscopy Identification of characteristic bands in infrared spectra confirmed the integrity of crystal lattice with minor changes over substitution. The morphological features showed minimal differences from the parent material. Biological evaluations showed the successful seeding of amorphous apatite within two days of SBF immersion and the antibacterial properties were enhanced upon incorporation of Zinc and Silver as compared to pure phase. Moreover, MTT assay of samples with MG-63 Cell lines showed proper cytocompatibility at low release concentration that decreases with an increase in release concentration of samples.[3]

References:

1. Shen, Y., Tok, A. and Dong, Z. Journal of the American Ceramic Society, 2010, 93, 1176– 1182. 2. Daniel Arcos, María Vallet-Regí, Acta Biomaterialia, 2010, 6, 2874–2888 3. Fu YF, Chen DM.. Journal of Oral Tissue Engineering. 2005,2(2),76-80

197

P106: Piezoelectric Sensors based on Electrospun PVDF and its Blends with Aromatic Hyperbranched Polyester

Pulak Pratik Ganesha, R. Gunasekhara, B. Indumathya, M.S. Rezab, Hongdoo Kimb,**,A. Anand Prabua,* a Department of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India b Department of Advanced Materials Engineering for Information & Electronics, Kyung Hee University, Gyeonggi-do 17104, Korea

In this study, aromatic hyperbranched polyester of first generation (Ar-HBP-G1) was synthesized using solution polycondensation of pentaerythritol (PE) as core molecule, diphenolic acid (DPA) as monomer and DMF as solvent at 130 °C for 23 h under inert atmosphere. The synthesized Ar-HBP- G1 was characterized using spectral (FTIR-ATR, NMR) and thermal analyses (DSC, TGA). Reaction kinetics studied using FTIR data was used to optimize the polymerization conditions. Further, electrospinning of neat PVDF and its blends with Ar-HBP-G1 as a function of varying HBP content (0, 10, 20, 30 and 40 wt.-% of Ar-HBP w.r.t. PVDF content) were carried out under controlled electrospinning conditions, and studied for their crystallization behaviour using FTIR and XRD analysis. FTIR quantitative analysis showed higher β-crystallinity in PVDF with increasing Ar-HBP content which is a favourable condition for fabricating high performance piezoelectric sensor devices. Electrospun nanoweb samples were measured for their piezoelectric output signals under applied pressure of 1 kgf and released periodically at 1.0 Hz. Among the four samples, PVDF/HBP-G1

(90/10) sample exhibited higher peak-to-peak (Vp-p) piezoelectric output signal (+6.42 V) than neat PVDF (+0.95 V), PVDF/HBP-G2 (90:10) (+4.03 V) and PVDF/HBP-G3 (90:10) (+4.13 V). Piezoelectric signals were also measured by varying load and frequency of the sensor, which showed increasing output voltage compared to neat PVDF. From the Vp-p data, it can be concluded that the addition of Ar-HBP to PVDF plays a vital role in improving its piezoelectric characteristics, which signifies the importance of this study. Acknowledgement: The authors (R.G. and A.A.P) wish to thank CSIR, Government of India for supporting this study under CSIR-EMR-II scheme (03(1450)18/EMR-II dt.05-06-2018). A.A.P also thank VIT for providing „VIT SEED GRANT‟ for carrying out this research work.

References:

198

P107: What makes „Bromophenol Blue‟ YELLOW in Methanol?

V. Sabareesh1,*, Aaheli Ghosh2, Adrita Das2 and Agniruudrra Sinha2

1.Advanced Centre for Bio Separation Technology (CBST), 2.School of Bio Sciences and Technology (SBST),Vellore Institute of Technology (VIT), Vellore, Tamil Nadu – 632 014, India.

Bromophenol Blue (BPB) is a widely and routinely used dye in gel electrophoretic experiments for nucleotide and protein analysis. It is also used as an acid-base indicator to monitor pH variations in aqueous solutions. In aqueous solutions, BPB can exist in two forms: neutral or anionic form (Figure 1).1 While, several studies involving BPB have been carried out in aqueous solutions, only a few investigations have been done in organic solvents. Therefore, we wanted to perform solvatochromic experiments in different organic solvents, such as, methanol, acetonitrile and acetone. For the sake of comparison, UV-Visible spectroscopic data were also acquired in water at near-neutral pH (pH ~ 6). Interestingly, we found that BPB in organic solvents appear as „Yellow-color‟, whereas it gives blue color in water (pH ~ 6).

OH Br Br OH Br Br Br Br

O - O OH O O O S S O Br O Br

Neutral Form (Ring-Closed) Anionic Form (Ring-Opened) To corroborate this color change, we surmise or hypothesize that BPB might exist in neutral ring- closed form in organic solvents, whereas the ring-opened anionic form is responsible for it to be in blue color in water (pH ~ 6). To test this hypothesis, we chose to do experiments using mass spectrometry (MS), in particular, of electrospray ionization (ESI) based, since it is possible to unambiguously determine „intact molecular mass‟ (without or negligible molecular fragmentation) by ESI-MS. Not only intact molecular mass, but it is also possible to obtain information regarding the number of charges on the molecule, through ESI MS. Thus, ESI - MS data were acquired separately for BPB solution prepared in methanol and BPB solution dissolved in water (pH ~ 6). The data were recorded in both positive and negative ion modes and the samples were introduced into the mass spectrometer (Quattro Premier XE, Waters) by direct infusion method. The ESI-MS data indicate that the transition from the „blue color to yellow color‟ of BPB upon changing the solvent from water to methanol may not be due to change from its ring-opened anionic form to ring-closed neutral form. In other words, charge on the BPB molecule may not be contributing for its solvatochromic behaviour in the solvents that have been chosen in this study. Further studies are underway for applying other spectroscopic techniques such as Infrared spectroscopy and Nuclear Magnetic Resonance spectroscopy to understand, which form of the molecular structure is responsible for the yellow color of BPB in methanol. Reference: 1. Madusudan; Vijayan M. Protein Engineering, Design and Selection 1992, 5, 399-404.

199

P108: Development of novel Ruthenium (II) and Iridium (III) based monometallic, bimetallic and heterobimetallic scaffolds for theranostic application in treatment of cancer

Nilmadhab Roy, Priyankar Paira

Department of Chemistry, School of Advanced Sciences, VIT, Vellore-632014, Tamilnadu, India

We are in a great menace due to unrestricted increase of third most fatal disease, cancer as we are still unable to discover appropriate medicine to defeat cancer permanently. Although there are some market available drugs, they are associated with lots of demerits in treatment of cancer and thereby they are gradually losing their importance. From that point of view, our main objective is to find out the suitable medicines capable of diagnosing as well as killing of cancer cells and thus we have aspired to develop i) target specific, ii) cytoselective rendering the normal cell unaffected, iii) water soluble, iv) cancer cell permeable, v) luminescent drug to get rid from the grip of cancer by using the drug theranostically, i.e. detection and destruction of cancer cell simultaneously. In order to achieve our goal, we have tried to prepare novel Ru(II) and Ir(III) based bi metallic and hetero bimetallic drugs in our laboratory using environmentally benign “Green Methodology” in treatment of cancer theranostically. The interesting feature of our scaffolds are the presence of two different metals in a same moiety which can fulfill both the requirements of detection and destruction of cancer cell by using only one drug at a time as the attachment of iridium metal makes the scaffold more fluorescent by shifting the emission wavelength to NIR region and compels the scaffolds to act as a good anticancer agent along with the presence of ruthenium metal. It is noteworthy that we already succeeded upto in vitro study with that scaffolds and hope it will help in cancer treatment and will act as live cell imaging probe in near future due to having excellent anticancer activity with good fluorescent property.

References: 1. Subran S. K., Banerjee S., Mondal A., Paira P., New J. Chem., 40, (2016), 10333. 2. Sarkar B, Mondal A, Madaan Y, Roy N, Moorthy A, Kuo YC, Paira P, Dalton Transactions (2019), 48 (32), 12257-12271 3. Mondal A., De S., Maiti S., Sarkar B., Sk A. K., Jacob R., Moorthy A., and Paira P.,Journal of Photochemistry and Photobiology B: Biology, Vol. 178, (2018), pp 380-394.

200

P109: Simple analytical method for the estimation of six potential genotoxic impurities in Tenofovir disporxil maleate drug using GC-MS technique

S. Elumalai, S.Senthilkumar*

Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology (VIT), Vellore–632014.

Tenofovir disoproxil maleate is an oral prodrug of Tenofovir, which is a nucleoside reverse transcriptase inhibitors (NRTIs) with activity against retroviruses, including HIV-1 & 2 and Hepadnaviridae. Six potential impurities, viz., ethyl bromide, chloromethyl methyl carbonate, chloromethyl ethyl carbonate, chloromethyl n-propyl carbonate, dichloromethyl isopropyl carbonate and chloromethyl-N,N-diethyl carbamate have been scrupulously chosen from specific route of synthesis and evaluated for their genotoxicity using LAZAR toxicity prediction in-silico model QSAR prediction software, which were showing structural alert for genotoxicity, therefore chosen them this study. These impurities are highly reactive in nature, and their detection and quantification were always challenging as the maximum permissible daily dose is 5 ppm based on TTC and recovery was also impacted because of the sample matrix interference. Therefore, the analytical technique engaged should be versatile, simple, selective, cost effective yet accurate. In order to overcome these challenges, we developed an analytical methodology using a hyphenated analytical technique (GC-MS) with easy sample extraction procedure (to overcome the matrix interference). The detection limits of each impurity arrived using this method was around 0.07 ppm whereas the quantification limits were approximately around 0.21 ppm. The method was linear over quantification limit to about 7.0 ppm (i.e., 120% of the actual limit). This method was fully validated in compliance with ICH Q2 R1 requirement with the parameters of system suitability, specificity, linearity, LOD, LOQ, method precision, intermediate precision and robustness.

201

P110: Development of a Calcium Phsophatebased Bone Adhesive which Aims to Repair Cranofacial Fractures

Nidhi Nair

Department of Bioscinces, School of Biosecienceand Technology,Vellore Institute of Technology Vellore–632014.

Conventional bone adhesives often used bone bonding agents to adhere the bone fragments together. Bone adhesives used earlier had higher mechanical strength but lower biocompatibility. The introduction of calcium phosphate based bone cements opened possibilities for adhesives which mimic the natural bone environment. This study aims to form a calcium phosphate based bone adhesive consisting of polydopamine and oxidised guar gum which has improved mechanical and cytocompatible properties. This also strives to overcome the impediment of the brittle nature of calcium phosphate cements. The final calcium phosphate cement has better anti-washout property and faster setting time owing to guar gum. Formation of hydroxyapatite when polydopamine is added to the calcium phosphate powder helps to increase the compressive strength of the cement as well as acts as a precursor for the effective regeneration of the bone.

202

P111: Rheological behaviour of hydroxypropylcellulose (HPC) hydrogel in the presence of surfactant

N. Shubhaschandra Singh

Department of Chemistry, D.M College of Science, Imphal , Dhanamanjuri University Manipur

Hydroxypropylcellulose (HPC) (nonionic water soluble polymer) readily forms hydrogel with iodine [1]. HPC-iodine hydrogel was found to be enhances gelling process on the addition of sodiumdodecylsulphate (SDS) (anionic surfactant). The addition of borax in the HPC-iodine hydrogel exhibited as a stronger hydrogel [2, 3] with G′ greater than G″ throughout the experimental frequency range than the HPC-iodine hydrogel in presence of SDS (Figure 1). The behaviour is explained by the preferential occupation of the active sites of the HPC by the borax through di-diol complexation [2-5]. Therefore, borax has shown comparatively higher affinity towards HPC than both SDS and iodine (Figure 2). DSC profiles of the HPC-iodine hydrogels also support the proposition of preferential occupation of the active site of HPC despite showing lower gel melting point temperature.

Figure 1: Plot of G′ or G″ (Pa) vs  (rad/sec) for Figure 2: Plot of G′ or G″ (Pa) vs  (rad/sec) for HPC-Iodine hydrogel in presence of borax HPC-Iodine hydrogel

References:

1. Homendra, N.; Shubhaschandra, S.N., J. Phys. Chem.B 2007, 111, 4098-4102 2. Tayal, A.; Pai, V.B.; Khan, S.A., Macromolecules 1999, 32, 5567-5574. 3. Carlsson, A.; Karlström, G.; Lindman, B., Colloids and Surfaces 1990, 47, 147-165. 4. Deguchi, S.; Kuroda, K.; Akiyoshi, K.; Lindman, B.; Sunamoto, J., Colloid and Surface A:Physicochemical and Engineering Aspects 1999, 147, 203-211. 5. Khutoryanskiy, D.V.V.; Cascone, M.G. ; Lazzeri, L.; Barbani, N.; Nurkeeva, Z.S.; Mun G. A. Dubolazov, A.V., Polymer International 2004, 53, 307-311.

203

P112: Facile Synthesis of Quasi-spherical, Hexagonal and Triangular Silver Nanoparticles at Room Temperature

Salima Begum, R.K. London Singh*

Department of Chemistry.D.M. College of Science, Dhanamanjuri University, Manipur. )

Rapid and stable green synthesis of silver nanoparticles at room temperature is still a challenge to the nanotechnologists. Amongst the metal nanoparticles, silver nanoparticle is most attracted.1 Synthesis of silver nanoparticles using gallic acid as reducing agent and starch as stabilising agent at room temperature is reported in this paper. UV-visible studies confirmed the formation of silver nanoparticles by the appearance of surface plasmon resonance (SPR) band at 443 nm and found stable for months. XRD studies revealed the formation of face centre cubic structure of silver crystal with preferential orientation along (111) plane with crystallite size of 9.32 ± 1.31 nm. TEM image showed the formation of quasi-spherical, highly facet hexagonal silver nanoplates and triangular silver nanoparticles. EDX analysis confirmed the Ag crystal by the presence of energy peak at 3 eV. Stabilisation of the nanoparticles with starch is supported by FTIR analysis. The synthesised silver nanoparticles showed catalytic activity in the degradation of crystal violet (CV) with sodium hydroxide and finds potential application in the removal of toxic dye from industrial effluents and environment.2

Figure 1: SPR of starch-stabilised AgNPs Figure 2: TEM micrograph of synthesised AgNPs

Figure 3: Catalytic degradation of CV with NaOH in the presence of starch-stabilised AgNPs

References:

1. Sharma, K.; Singh, G.; Kumar, M.; Bhalla, V. RSC Adv., 2015, 5 (33), 25781–25788 2. Goswami, M.; Baruah, D.; Das, A.M. New J. Chem., 2018, 42, 10868-10878

204

P113: Sierpiński triangle to pyramid via concerted interplay of weak interactions

Rajarshi Sarkar*,a,g Tingzheng Xie,a Kevin J. Endres,b Wang Zilu,a Charles N. Moorefield,c Mary Jane Saunders,d Anil K. Patri,e Chrys Wesdemiotis,b* Andrey V. Dobrynin, George R. Newkomea,b,f*

Depts of aPolymer Science and bChemistry, The University of Akron, Akron, Ohio 44256 USA; cDendronex LLC, 109 Runway Drive, Lubbock, Texas 79416 USA; dDepartment of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33431 USA; eNCTR-ORA Nanotechnology Core Facility, National Center for Toxicological Research, U.S. Food & Drug Administration, HFT-30, 3900 NCTR Road, Jefferson, Arkansas 72079 USA; fCenter for Molecular Biology and Biotechnology, Florida Atlantic University, 5353 Parkside Drive, Jupiter, Florida 33458 USA, gSVKM‟S NMIMS Indore, Super Corridor Rd, Gandhi Nagar, Indore, Madhya Pradesh 452005

: We have demonstrated that self-assembled Sierpiński triangle with alkylated corners undergoes further self-assembly to produce megastructural Sierpiński pyramids, driven by the facile lipophilic- lipophilic association and complementary perfect-fit of building blocks. The formation of such 2D & 3D structures were verified by combination of the microscopic and multiscale simulation techniques.

Figure caption/Scheme: Self-assembly of Sierpiński pyramid

References:

1. Daum, B.; Quax, T. E. F.; Sachse, M.; Mills, D. J.; Reimann, J.; Yildiz, Ö.; Häder, S.; Saveanu, C.; Forterre, P.; Albers, S.-V.; Kühlbrandt, W. Proc. Natl. Acad. Sci. 2014, 111, 3829. 2. Sarkar, R.; Guo, K.; Moorefield, C. N.; Saunders, M. J.; Wesdemiotis, C.; Newkome, G. R. Angew. Chem. Int. Ed. 2014, 53, 12182. 3. Sarkar, R.; Guo, Z.; Li, J.; Burai, T. N.; Moorefield, C. N.; Wesdemiotis, C.; Newkome, G. R. Chem. Commun. 2015, 51, 12851.

205

P114: Imidazolium ionic liquids towards the Mg/S batteries

Santosh N. Chavan1*, and Vatsala Rani J. 1*

Polymer and Functional Material Division 1 Indian Institute of Chemical Technology Hyderabad, Hyderabad, India

Rechargeable magnesium (RMB) battery has been promising candidate1,2 for future battery generation due to its safety Mg anode. In this combination sulphur cathode is one of the safe, low- cost and high volumetric electrochemical storage system.3,4 Electrolyte is one of the challenging task in this system due to Mg compatibility and sulphur (polysulfide) solubility.1 Common anion used in 2+ 2+ - electrolyte system provides fast movement of [Mg (BF4)n] and [(Mg (TFSI )n] adduct as well as suppress the polysulfide solubility due to anion concentration. Effectively the passivation of Mg2+, intercalation into electrodes and transportation get enhanced. These effect truly exist into Mg2+ - - kinetics in the Mg/S batter cycling and conductivity results. The BF4 and TFSI WCA (weakly - - coordinating anion) tuned with imidazolium ionic liquid and common anion Mg (BF4 )2 and Mg (TFSI )2 into Mg/S battery with sulphur cathode material. The fluorinated anionic ionic liquid prohibit the dissolution of sulphur than the localized negative charge anionic ionic liquid and effectively enhance in the suppressing polysulfide shuttle effect. This is shown by longer cycle capacity in full cell and electrolytes are analysed after s by UV, electrode surfaces by SEM-XPS.

References:

1. Wang, P.; Buchmeiser, M. R. Adv. Funct. Mater., 2019, doi.org/10.1002/adfm.201905248. 2. Chavan, S. N.; Tiwari, A.; Nagaiah, T. C.; Mandal, D. Phys. Chem. Chem. Phys. 2016, 18, 16116. 3. Wang, J.; Lin, F.; Jia, H.; Yang, J.; Monroe, C. W.; NuLi, Y. Angew. Chem. Int. Ed. 2014, 53, 10099. 4. Kanakaiah, V.; Latha, M.; Sravan, B.; Palanisamy, A.; Rani, J. V. J. Electrochem. Soc. 2014, 161, A1586.

206

P115: Ionic Liquid-Immobilized Proline(s) Organocatalyst Catalysed One-Pot Multi-Component Mannich Reaction under Solvent-Free Condition

Prabhakara M D, Barnali Maiti*

Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology VIT, Vellore– 632014.

A highly efficient clean and simple methodology has been established for the one-pot multicomponent Mannich reaction using ionic liquid immobilized proline(s) organocatalyst under solvent- free conditions. The three-component comprising of substituted acetophenones substituted aromatic aldehydes and substituted aromatic amines underwent Mannich reactions in one-pot in presence of 7 mol% of ionic liquid immobilized proline(s) organocatalyst to provide β-amino carbonyl compounds in 2-3 h at room temperature with excellent yields. This methodology delivers several advantages such as short reaction time, mild reaction conditions, multi-component approach, transition metal-free, low catalyst loading percentage, and solvent-free synthesis. The ionic liquid immobilized proline(s) organocatalyst was recycled and reused six times without significant loss of its catalytic activity.

References:

1. Miao, W.; and Chan, T. H. Adv. Synth. Catal. 2006, 348, 1711. 2. Lisnyak, V. G.; Kucherenko, A. S.; Valeev, E. F.; Zlotin, S. G. J. Org. Chem. 2015, 80, 9570.

207

P116: Photoinduced Solvatochromic Properties and Biomacromolecular Interaction of New Indazole Derivatives.

A.Roniboss, Kaushik Chanda, Balamurali MM*.

Chemistry Division.Vellore Institute of Technology,Chennai campus, Chennai,India.

Heterocyclic compounds obtained by diversity-oriented synthesis are widely found in natural products and bioactive molecules and have a vast array of applications across numerous fields. Over the last decade, researchers in drug discovery have paid more attention to indazole derivatives, as this moiety acts as a bioisostere of indoles and benzimidazoles. Indazole derivatives scarcely occur in nature, but molecules with 2H-indazole moieties have a wide range of biological properties, such as antitumor activity, HIV-protease inhibition, anti-HIV activities, anti-inflammatory activity, modulation of estrogen receptors and anti cancer activity, antifungal, antibacterial. Moreover, in addition to these biological activities, indazole scaffolds also exhibit photophysical properties for potential theranostic applications. Herein we discuss the various electronic properties based on the effect of substituents and the ability of these derivatives to interact with biomacromolecules.

References:

1. Hu, F.; Szostak, M. Adv.Synth.2015, 357, 2583-2614. 2. Behrouz, S. J. Heterocyclic. Chem.2017, 54, 1863-1871.

208

P117: Determining the Role of Mechanical Strength on EMT using a Novel PVA-PEG-HAp 3-D Scaffold

Simrit Safarulla1, Amit Kumar Jaiswal2*

1School of Biosciences and Technology, VIT, Vellore-632014, 2Centre for Biomaterials, Cellular, and Molecular Theragnostic, VIT, Vellore-632014

Epithelial to mesenchymal transition (EMT) is the primary culprit of metastatic cancer. Recent evidences show that sarcoma, a soft tissue cancer, also exhibits EMT like behaviour which results in cancer cell invasion into the lymph nodes making the prognosis worse.1 EMT is influenced by its microenvironment and one such property, tissue stiffness has been accepted as a cancer biomarker.2 This study is an attempt to elucidate the mechano-sensitivity of primary bone cancers in a 3-D bone microenvironment. A polyvinyl alcohol/ poly ethylene glycol/ hydroxy apatite (PVA/PEG/HAp) scaffold was prepared by 6 consecutive freeze-thaw cycles. PVA, PEG and HAp at 14%(wt./v), 6% (wt./v) and 20% (wt./wt.) showed impressive compressive strength of 24.07±12.06 MPa in dry conditions. The swelling index and the qualitative degradation assay proved the water retention capability and stability of the scaffold.

References:

1. Sannino, G.; Marchetto, A.; Kirchner, T.; Grünewald, T. G. P. Cancer Res. 2017, 77 (17), 4556 LP – 4561. https://doi.org/10.1158/0008-5472.CAN-17-0032. 2. Martinez, B.; Yang, Y.; Harker, D. M. R.; Farrar, C.; Mukundan, H.; Nath, P.; Mascareñas, D. Frontiers in Cell and Developmental Biology . 2019, p 199.

209

P118: A comparative Catalytic Study of Hydrotalcite/SBA-15 Nanocomposites for the Efficient Conversion of Biomass-derived Substrates

Marimuthu Manikandan, Ayyappan Arjunan, Palanivelu Sangeetha*

Chemistry Division, School of Advanced Sciences,Vellore Institute of Technology, Vandalur - Kelambakkam road,Chennai – 600 127.

Hydrotalcites (HT) have a broad spectrum of applications as robust heterogeneous catalysts for various chemical transformations.1 The reactivity of HT based catalysts can be tailored by introducing siliceous material either into the internal framework or at the external framework. The modification on the HT framework with silica based mesostructure that gives rise to the formation of versatile Lewis base, Brønsted base and redox‐active catalytic sites.2 Understanding the nature and catalytic role of such sites is crucial for guiding the design of new and improved HT/SBA-15 based nanocomposite catalysts.3 This work presents the comparative evaluation on the catalytic performance of HT@SBA- 15 and SBA-15@HT for biomass conversion. The influence of the preparation methods, including one-pot synthesis and post-synthetic intercalation, was examined. The textural and physicochemical properties of synthesized materials have been evaluated by XRD, SEM, TEM, and CO2-TPD characterization studies. Both composites exhibited distinct catalytic activity towards the conversion of biomass derived substrates to fine chemicals. Characterization studies conferred that the fine-tuning of basic sites on the nanocomposites has a vital role on the catalytic performance. The role of active sites in addressing the structural features in nanocomposites and understanding reaction pathway relations is discussed. Special attention is devoted to such reactivity phenomena as active site cooperativity, catalyst multifunctionality as well as confinement‐enhanced multisite reactivity commonly encountered in mesoporous catalysis.

Figure: Graphical representation of the comparative catalytic performance of hydrotalcite/SBA-15 nanocomposites

References:

1. Manikandan, M.; Prabu, M.; Ashok Kumar, S. K.; Sangeetha, P.; Vijayaragavan, R, Mol. Catal. 2018, 460, 53-62. 2. Creasey, J. J.; Parlett, C. M.; Manayil, J. C.; Isaacs, M. A.; Wilson, K.; Lee, A. F, Green Chem., 2015, 17, 2398-2405. 3. Sun, L.B.; Liu, X. Q.; Zhou, H. C, Chem. Soc. Rev., 2015, 44, 5092-5147.

210

P119: N-Heterocyclic Carbene Catalysed acylation of 2-oxindoles using aldehydes to form 3- alkenyloxindoles by C-C bond formation

Karthick Muthuvel,Thirumanavelan Gandhi*

Department of chemistry, School of Advanced science,Vellore Institute of Technology, Vellore Tamil Nadu-632014

N-Heterocyclic carbenes (NHCs) have emerged as a powerful class of organocatalysts that mediate a variety of organic transformations1. The diverse reactivity of NHCs in organocatalysis is due to the possibility of different modes of action. Carbon–carbon bond forming reactions of enolates and their synthetic equivalents constitute the bedrock of organic synthesis. Herein we report the NHC catalysed acylation of 2-oxindoles using aldehydes to form 3-alkenyloxindoles by C-C bond formation in moderate to good yields under mild reaction conditions. The reaction likely proceeds via the generation of Breslow intermediate2. It is a 100% atom-economic process.

References:

1. Menon, R. S; Biju, A. T; Nair, V. Beilstein J. Org. Chem. 2016, 12, 444. 2. Breslow, R. J. Am. Chem. Soc. 1958, 80, 3719.

211

P120: Multi-Component approach for synthesis of quinolinyl-1,4-dihydropyridines and in vitro evaluation of anticancer activity against MCF7

Selvendran Suresh,a Biswarup Basu,b Souvik Dos,b Kamran Waidha c Saravanakumar Rajendrana*

aChemistry division, School of Advanced Sciences, Vellore Institute of Technology Chennai Campus, Chennai-600 127, Tamilnadu, India.bChittaranjan National Cancer Institute, Chitranjan, S.P. Mukherjee Rd,Kolkata-700026. cAmity Institute of Biotechnology, Amity University Uttar Pradesh, , Noida-201303,India

Quinolines and 1,4-dihydropyridines are common to bio-active molecules and many commercial drugs.1 Here we present a highly efficient and chemo-selective process for the synthesis of polysubstituted quinolinyl-1, 4-dihydropyridines using a one-pot multicomponent approach and evaluated their anticancer activity against the breast cancer cell line, MCF 7 via MTT assay in vitro. Tetrazolo [1,5-a]quinoline-4-carbaldehyde, 3-oxo-3-phenylpropanenitrile, and β-enamine were reacted in the presence of trimethylamine to obtain highly functionalized quinolinyl-1,4-dihydropyridines. The product formation was ascertained by various spectroscopic analysis. Molecular structure of one of the quinolinyl-1, 4-dihydropyridine derivatives is confirmed by single crystal X-ray diffraction. Among the compounds evaluated, SKS19 was the most cytotoxicity, IC50 = 7.87 µM. Molecular docking was conducted to understand the mechanism of inhibition. The above study corroborate quinolinyl-1,4- dihydropyridines as a valuable scaffold to develop anticancer drug.

Scheme 1: Synthesis of polysubstituted quinolinyl-1, 4-dihydropyridines.

References:

1) Isaivani, D.; Padmini, V.; Bhuvanesh, N. ACS Comb. Sci. 2016,18, 5, 236. 2) Sandip, V. B.; Manish, P. P. Ind. J. Chem., 2012, 51B, 1388.

212

P121: Thermal and chemical stability studies of „Cs‟ and „Sr‟ ions immobilized simulated crystalline apatite ceramic wasteform

Ramya Ravikumar and Buvaneswari Gopal *

Department of Chemistry, School of Advanced Sciences VIT, Vellore-632 014

High-level nuclear waste stream constitutes both short- and long-lived radionuclides. Among the short-lived radionuclides, caesium (Cs) and strontium (Sr) are the most heat generating fission products that is also highly mobile in aqueous media.1 Hence it is vital to contain them in a stable host matrix (primary barrier system) in order to isolate from biosphere.2,3 Lacunar apatite compound

NaPb4(PO4)3 was examined for immobilization of „Cs‟ and „Sr‟ ions, based on which simulated wasteform of the formula Na0.9Cs0.1Pb3Sr(PO4)3 was designed. The X-ray diffraction analysis reveals that the obtained apatite is a single phasic and isostructural with host matrix [NaPb4(PO4)3]. The wasteform shows improved thermal stability and exhibits anisotropic thermal expansion behavior with no phase transformation or any kind of thermal distress in the temperature range studied (RT- 973K). -6 -1 The calculated average thermal expansion co-efficient (αavg) is found to be 14.4 x 10 K with preferential crystallographic expansion along c-axis. The chemical durability of the wasteform was studied by MCC-5 dynamic leach test. The results indicate incongruent leaching of ions and negligible + -6 -8 2 -2 2 -4 -6 2 - leaching of Cs ion, with LRCs =10 - 10 g/m /d, LRNa= 10 g/m /d, LRPb = 10 - 10 g/m /d, LRSr =10 3 -4 2 -2 -3 2 -10 g/m /d and LRP =10 -10 g/m /d.

References:

1. Forsberg, C. W. Nucl. Technol. 2017, 131 (2), 252–268. 2. Neumeier, S.; Arinicheva, Y.; Ji, Y.; Heuser, J. M.; Kowalski, P. M.; Kegler, P.; Schlenz, H.; Bosbach, Di.; Deissmann, G. Radiochim. Acta 2017, 105 (11), 961–984. 3. Orlova, A. I.; Ojovan, M. I. Materials. 2019, 12 (16), 2638.

213

P122: Photocatalytic activity study of SnTiO3-g-C3N4 nanocomposites towards degradation of toxic rhodamine B dye from polluted water

Vignesh A., Boya Palajonna Narasaiah and Badal Kumar Mandal*

Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore- 632014, Tamilnadu, India.

Nowadays synthesis of photocatalytic materials is becoming important due to severe water pollution from wastewater discharge of textile and pigment industries. Remediation of toxic organic dyes from polluted water is an essential task to clean up water for avoiding further damage of our environment. Hence scientists are searching new materials for degradation of organic dyes from water. In this regards researchers are synthesizing novel materials which are capable of degrading organic dyes under irradiation of visible light. In this study we have synthesized graphitic carbon nitride nanomaterials and its metal oxide nanocomposites for the degradation of rhodamine B (Rh-B) dyes after irradiation of visible as well as UV light (1-4). After characterization of the synthesized nanomaterials using different instrumental techniques we have checked the effects of pH, photocatalyst dose and different metal oxide graphitic carbon nitride nanocomposites on degradation efficiency of Rh-B dyes. In addition, we have compared the degradation efficiency of different nanocomposites between visible and UV light exposure (Fig. 1).

Figure 1: Photodegradation of Rh-B by SnTiO3-g-C3N4 nanocomposites under UV and visible light exposure

References:

1. Kumar, A., Kumar, A., Sharma, G., Al-Muhtaseb, A.H., Naushad, M., Ghfar, A.A., Stadler, F.J., Chemical Engineering Journal 2018, 334, 462–478. 2. Li, G., Nie, X., Gao, Y., An, T., Appl. Catalysis B: Environ. 2016, 180, 726–732. 3. Jo, W.-K., Natarajan, T.S., Journal of Colloid and Interface Science 2016, 482, 58–72. 4. Kumar, A., Kumar, A., Sharma, G., Al-Muhtaseb, A.H., Naushad, M., Ghfar, A.A., Stadler, F.J., Chemical Engineering Journal 2018, 334, 462–478.

214

P123 Sol-gel Combustion Synthesis of Merwinite and its Biomedical Applications Subhashree Praharaj, Senthil Kumar Venkatraman, and Sasikumar Swamiappan a Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore- 632014, Tamil Nadu, India

The multidisciplinary attribute of biomaterials requires scientists to contrive and concoct the material, engineers to design and fabricate the prosthesis, and physicians to swot the response of natural tissues on artificial biomaterials implanted in the body. Globally, it has been appraised that about 60% of artificial bone substitutes are mustered of bioceramics. Thus, much enthrallment has been rafted towards the use of different bioceramics for bioactive fixation of artificial implants. Energy efficient sol-gel combustion method has been adopted for the synthesis of merwinite. Citric acid was employed as a fuel while nitric acid played dual role as catalyst and oxidizer during gelation and combustion respectively. The obtained merwinite was characterized by XRD and FT-IR to confirm the phase purity. SEM/EDAX analysis wasemployed to study the morphology and elemental composition of the material. The bioactivity of merwinite was investigated by immersing the scaffold in SBF. The surface after immersion reveals the presence of hydroxyapatite layer over the surface. The presence of antibacterial activity was confirmed using the zone of inhibition occurred around the test samplein the bacterial lawn culture. The mechanical strength was found to be in the range of cortical bone.

Keywords: Merwinite, Citricacid, Combustion, Bioactivity, Antibacterial activity and Mechanical strength

215

P124 A Review on Synthesis of Sugar Derived Biomolecules and Its Applications in Asymmetric Synthesis

M. Priyanka, I. Usha Naga Lakshmi, P. Sushma, A. Srivani, R. Jayachandra and

Sabbasani Rajashekar Reddy*

Synthesis of D-Glucose, D-Ribose, D-Xylose, D-Galactose derived chiral ionic liquids by simple approaches are described, which are characterised by NMR, ESI-MS. Carbohydrate based CIL‟s are chemically stable and have used as reusable solvents and chiral catalysts for asymmetric Michael addition reactions. Developed CCIL‟s were successfully employed in asymmetric Michael addition reactions to produce Michael adducts in high yield with moderate enantio-selectivity. Further the CCILs explored for the chiral discrimination of racemic Mosher‟s Acid.

Key words: Carbohydrates, Natural resources, Chiral Ionic Liquids, Asymmetric synthesis

Scheme 1: Recent work from our laboratory using natural carbohydrates

References:

1. (a). R.Jayachandra and S. R, Reddy, Trends in Carbo. Res. 2015, 7, 60. (b). R.Jayachandra, R. Lakshmipathy and S. R, Reddy. J. Mol. Liquids 2016, 219, 1172. (c). R. Jayachandra and S. Rajasekhara Reddy* Balakrishna. Chemistry Select. 2016, 1, 2341-2343. (d).. R. Jayachandra and S. R, ReddyR. Sc Advances. 2016, 6, 39758. (e). R. Jayachandra , S. R, Reddy, and R. Lakshmipathy. Environmental Progress & Sustainable Energy. 2019, S1-S450.

216

P125 An Overview on Regioselective Cascade Approaches for the Synthesis of 6H- Benzochromene, 6H-Benzochrome-6-ones and its Scope

Pooja Garg, B.Muralidhar, Gracevictoria Govada, I. Usha Naga Lakshmi, and Sabbasani Rajasekhara Reddy* . Department of Chemistry, School of Advanced Science. Vellore Institute of Technology, Vellore.. Polycyclic heterocycles with annulations of benzochromene framework are widely distributed in the nature and have great biological and pharmacological significance. Numerous natural products in which benzene ring is fused angularly or linearly to a chromene ring system have been isolated, synthesized, and characterized by various spectroscopy techniques and single crystal X-ray diffraction analysis. Depending upon the fusion of benzene ring to different sites of chromene ring, various benzochromene systems such as benzo[c]-, benzo[f]-, benzo-[g]-, and benzo[h]chromenes are reported. Present work will describe the various synthetic strategies to construct the 6H- Benzo[C]chromene and 6-H Benzo[C]chromenone analogues and its scope.

Scheme.1:Synthesis of 6H-benzo[C]chromene and 6H-benzo[C]chromenone.

References:

[1] (a) Villuri, B.K.; Ichake, S.S.; Reddy, S.R.; Kavala, V.; Bandi, V.; Kuoand, C-W.; Yao, C-F.; J. Org. Chem.2018, 17, 10241. (b) Bandi, V.; Kavala, V.; Konala, A.; Hsu, C-H.; Villuri, B. K.; Reddy, S. R.; Lin, L.; Kuo, C-W.; Yao, C-F. J. Org. Chem.2019, 84, 3036. (c) Sachin, S. I.; Kumar, V. B.; Reddy, S. R.; Kavala,V.; Yao, C-F. Org. Lett.2019, 21, 2256. [2] (a) Muralidhar, B. and Reddy, S R Bull. Chem. Soc. Jpn.,2018, 91, 65.(b) Naidu, S.; and Reddy, S..R. RSC Advances.2016, 6, 62742.(c) Reddy, C. B. R.; Reddy, S.R.; Naidu, S. Catal. Commu.2014, 56, 50. [3] (a)Ramendra, P.; Vishnu Ji, R.Chem Rev. 2004, 114, 10476 (b) Iaroshenko, V.O.; Abbasi, M.S.A.; Villiger, A.; Langer, P. Tetrahedron Lett.2011, 52, 5910. (c) Bhattacharya, P.; Senapati, K.; Chattopadhyay, K.; Mandal, S.M.; Basak, A. RSC Advances2015, 5, 61562.

217

P126 Overview on Synthesis of Sugar Based Ionic Liquids for Sustainable Societal Applications

P. Krishnaraj, M.Priyaunka, R. Jayachandra and Sabbasani Rajashekar Reddy*

School of Advanced Sciences, Department of Chemistry, VIT University, Vellore-632014, India.

Sugars are the most abundant bio-organic molecules. Exploring these molecules into value added applications are most important area of research work due its nontoxic in nature wide availability. Applications of sugar derived ionic liquids were never been explored purification of water. However, carbohydrate based chiral auxiliaries, chiral catalysts and reagents have shown excellent applications towards asymmetric synthesis. Of late, our group reported the syntheses of sugar derived ionic liquids by simple synthetic approaches. Which are characterised by various analytical techniques. Of late, removal of toxic metals ion like Pd+2, Cd+2 etc., from the aqueous solutions is important area of research work. In this presentation, we are planned the overview the synthesis of sugar based ionic liquids and its applications in removal of toxic metals such as like Pd+2, Cd+2 etc., from aqueous solution. Key words: Carbohydrates, Synthesis, Sequestration and toxic metals

Scheme 1: Recent work from our laboratory using natural carbohydrates

References:

218

P127 Benzo [4, 5] thiazolo [3, 2-a] pyrimidine-3-carboxylate based Colorimetric Sensor for the Detection of Fe3+ and Cr3+ ions Shanthi Seenan and Kulathu Iyer Sathiyanarayanan* Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore-632014

ABSTRACT

Benzo [4, 5] thiazolo [3, 2-a] pyrimidine-3-carboxylate (4a) was synthesized. The changes in absorption properties of compound 4a in the presence of various cations were evaluated. Compound 4a can acted as colorimetric sensor for highly sensitive and selective detection of Fe3+ and Cr3+ in acetonitrile solvent. Using measurements of absorbance intensity, the binding constant for 4a+Fe3+ complex and 4a+ Cr3+ complex was found to be 1.958×108 M-1 and with the lower detection limit of 52 nM and 112 nM respectively.1H NMR titration,FT- IR, ESI-Mass spectrum, and Job's plot were taken to confirm the mechanism of the specific reaction and colorimetric sensing of 4a+Fe3+ and 4a+Cr3+.The application of compound 4a for the determination of Fe3+ in spiked samples of iron tablet in changed environmental water samples showed a satisfactory result with good recovery.

References: 1.Sahu, P. K.; Sahu, P. K.; Agarwal, D. D. Efficient and Facile Synthesis of Heterocycles and Their Mechanistic Consideration Using Kaolin. RSC Adv.2013, 3, 9854–9864.

2. Tripathi, M.; Reddy, P.; Rawat, D. Chemistry & Biology Interface. Chem. Biol.2014, 4, 1–22.

3. Qu, Q.; Wang, F.; Zhao, Q.; Chen, X.; Zou, W. A Colorimetric Fe3+ Sensor Based on an Anionic Poly (3, 4-Propylenedioxythiophene) Derivative. Sensors Actuators B Chem.2017, 244, 891–896.

4.Arockiam, J. B.; Ayyanar, S. Benzothiazole, Pyridine Functionalized Triphenylamine Based Fluorophore for Solid State Fluorescence Switching, Fe3+and Picric Acid Sensing. Sensors and Actuators, B: Chemical.2017, 242, 535–544.

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P128 Rational synthesis of tetrahydrodibenzophenanthridine and phenanthroimidazole as efficient blue emitters and its applications

ManojkumarDhanthalaThiyagarajana, UmamaheshBalijapallia, b, SohrabNasiric, DmytroVolyniukc, JurateSimokaitienecc, SathiyanarayananKulathuIyer*a, JuozasVidasGražulevi ius*c and *a Prof.Madhvesh Pathak

Department of Chemistry

SAS, Vellore Institute of Technology, Vellore-632014.

Ten luminophores based on tetrahydrodibenzophenanthridine (THDP) and phenanthroimidazole (PI) were designed, synthesized and characterized for their thermal, electrochemical, electro-optical, charge-transporting characteristics and electroluminescent properties. The blue luminophores exhibited high photoluminescence quantum yields of 66-93% in toluene solutions and of 5-59% in solid films. The highest values were observed for the derivative of THDP and PI containing methoxy group. The compounds showed close values of ionization potentials (5.74-6.11 eV) and electron affinities (2.71-3.06 eV). The selected compounds were tested in electroluminescent devices for the preparation of non-doped light-emitting layers. The best device fabricated using derivative of THDP and PI with methoxy groups showed blue electroluminescence with brightness of 10000 cd/m2 at high applied voltages. We performed DFT calculations, and observed lowest singlet-triplet gap (∆EST) values of 0.33 and 0.03 eV, oscillator strength (f) values of 0.034 and 0.008 for CN and NO2 derivatives. Interestingly, we observed that compounds 3g and 3i showed HOMO and LUMO levels of almost similar energy gap (Eg) of 3.60 eV and we observed deeper HOMO values of -5.30, -5.33 eV and LUMO values of -1.94, -2.77 eV.

Graphical abstract

References:

1. G. M. Farinola, R. Ragni, Chemical Society Reviews.2011, 40, 3467-3482.

2. H. Ulla, B. Garudachari, M. N. Satyanarayan, G. Umesh, A. M. Isloor, Optical Materials.2014, 36, 704-711

3. M. A. Baldo, M. E. Thompson, S. R. Forrest, Nature.2000, 403, 750-753

4. J. Tagare, S. Vaidyanathan, Journal of Materials Chemistry C.2018, 6, 10138-10173.

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P129 Ni(II) Assisted Catalytic Transfer Hydrogenation Reactions of Carbonyl Compounds

Rakesh R Panicker, Sadhana Venkatesh, Chayan Pandya and Akella Sivaramakrishna* Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore – 63 2014, Tamil Nadu, India.

The catalytic transfer hydrogenation reactions of a series of aromatic and aliphatic carbonyl compounds were investigated using divalent Ni(II)-diphosphine complexes of the type [L2NiCl2]

(where L2 = 1,1-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp) and 1,1-bis(diphenylphosphino)ferrocene (dppf)). This is a single-step reaction in the presence of potassium hydroxide and isopropyl alcohol to give corresponding alcohols. This protocol tolerates other sensitive functional group like olefinic double bonds, but also achieves high chemoselectivity. All the reactions were monitored by GC and GC-MS. The plausible mechanism was also discussed. The method reported in the present paper is simple, cost-effective and provides excellent conversions. Nickel-diphosphine complexes appear as a potential alternative to the expensive transition metal complexes.

Key words: Nickel(II)-diphosphine complex, catalytic transfer hydrogenation, carbonyl compounds, alcohols.

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P130 New Phosphine Oxide based Cerium (IV) Complexes: Synthesis, Structural Characterization and their Coordination Behaviour

Vijai Anand A S, and Akella Sivaramakrishna* Department of Chemistry Vellore Institute of Technology, Vellore, Tamilnadu, India. Pincode- 632014

The availability of a range of various lanthanoid metals, coupled with a large amount of different ligands, provides an effective way to systematically fine-tune the properties of the coordination complexes of lanthanides1.This helps to control their catalytic behaviour efficiently, such as chemoselectivity, enantioselectivity and diasterioselectivity. Reactions involving organolanthanoid catalysts involve mild inert reaction conditions. Hydrocarbon solvents are generally used for catalytic reactions as they are able to bind to the Lanthanide center. The presence of bulkier R groups can significantly affect the catalytic activity due to the steric demands of the ligands, which can hinder the association of the lanthanoid with the desired organic substrate, but also allows specificity to be built into the catalyst. The present work is mainly focused on synthesis of selected new cerium complexes using phosphine oxides as binders. But the literature on chemistry and applications of these complexes is very limited 2. The prepared cerium complexes were characterized by spectroscopic and analytical techniques. The coordination behaviour of these complexes with respect to solvent, nature of ligand, temperature and ligand crossover is investigated. Keywords: Cerium, Phosphine Oxide, Coordination behaviour, Organic reactions.

References: 1. Housecroft, C.E.; Sharp, A.G. J. Chem. Educ. (2003),80, 7, 747 2. Nair, V.; Balagopal, L.; Rajan, R.; Mathew, J. Acc. Chem. Res. (2004), 37(1), 21-30. and Coles, S. J.; Fieldhouse, S. J.; Klooster, W. T.; Platt, A. W. Polyhedron. (2019), 161, 346-351.

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P131 Photocatalytic Remediation of Environmentally Toxic Dyes by ZnTiO3/g-C3N4 Nanocomposites Sim Simon., Boya Palajonnala Narasaiah and Badal Kumar Mandal* Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore- 632014, Tamilnadu, India.

The dyes are hazardous to the environment. Even 1 mg/L of dye can cause serious problems to environments [1]. Dye concentration higher than 1mg/L caused by the direct discharge of textile effluents can give rise to contamination of water and soil which causes severe problems to ecosystem [2]. Hence, it is necessary to develop remediation methods through successive cheaper possible routes for making this toxic form of dyes or dye effluents to non- toxic form like mineral acids and H2O [3]. So, in this work we mainly focused on synthesis of ZnO, TiO2, ZnTiO2, g-C3N4, ZnO-g-C3N4, TiO2-g-C3N4 and ZnTiO2-g-C3N4 through a chemical route for dye degradation. Nanocomposites were characterized using XRD, UV- DRS, UV-Visible spectroscopy. The synthesized different nanocomposites were checked for the degradation of direct methylene blue under UV and Visible light using Heber photo reactor. Degradation of dyes was monitored periodically using UV-Visible spectroscopy. Results indicate that the synthesized nanocomposites exhibited higher degradation efficiency to MB dye under UV-irradiation within shorter time compared to visible light exposure. The results of this study suggest that the synthesized nanocomposites could be promising materials for photocatalytic degradation of dyes or environmental remediation.

Figure 1: Photodegradation of MB by ZnTiO3-g-C3N4 nanocomposites under UV and visible light exposure

References: 1. Li Li, Shu-Qing Sun, Yong-Xing Wang, Chuan-Yi Wang, Journal of Photochemistry and Photobiology A: Chemistry 2018, 355, 16-24. 2. Eunyong Jang, Dae Woong Kim, Seong Hwan Hong, Young Min Park, Tae Joo Park, Applied Surface Science 2019, 487, 206–210. 3. Masoud Salavati-Niasari, Faezeh Soofivand, Ali Sobhani-Nasab, Maryam Shakouri-Arani, AliYeganeh Faal, Samira Bagheri, Advanced Powder Technology 2016, 27, 2066-2075.

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P132 Synergistic effect of cinnamon-chitosan Schiff base in wastewater treatment Thandapani Gomathi*, E. Swetha and P.N. Sudha PG and Research Department of Chemistry, D.K.M. College for Women, Vellore, Tamil Nadu, India

The aim of this study was to evaluate the synergistic effect cinnamon and chitosan on the removal of methylene blue dye and chromium from aqueous solution. Ethanol extract of cinnamon bark was mixed with chitosan solution to prepare Cinnamon-chitosan Schiff base (ECCSB) and analyzed using FTIR and XRD for its formation and suitability for wastewater treatment. FTIR results confirmed the formation of Schiff base by showing band at 1647 cm-1. XRD analysis showed that the prepared cinnamon-chitosan Schiff base was amorphous in nature with the degree of crystalinity 9%. The porosity measured via liquid displacement method showed the porosity of 88.86% and the prepared Chitosan cinnamon Schiff Base showed good antioxidant and antimicrobial activity. In vitro biodegradation assay revealed that the time increases the percentage of degradation also increases. Batch adsorption study was carried out for the removal of methylene blue dye and chromium metal ion by varying the parameters such as pH, adsorbent dose, contact time and initial concentration. The experimental data were analyzed by the Langmuir and Freundlich isotherm models, the results were well fitted to the Frundlich isotherm model. The kinetics experimental data properly correlated with the pseudo second order kinetic model than the pseudo first order kinetics. The results indicate that ECCSB could be employed as the promising material for wastewater treatment even at low concentration.

Keywords: Cinnanon, Chitosan Schiff base, Methylene blue, Batch adsorption study

References: 1. Hossein, N.; Zahra, Z.; Abolfazl, M.; Mahdi, S.; Ali, K. Journal of Medicinal Plants Research, 2013, 7, 1339–1343. 2. Ismat, H.; Ali Mohammed, K.; Al Mesfer Mohammad I.; Khan, Mohd Danish; Majed, M. Alghamdi, Processes 2019, 7(4), 217.

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P133. Synthesis, Characterisation and Sorption studies for the removal of Cr (VI) using doubly grafted Chitosan oligosaccharide blend (COS – g – MAH - g – AA / PPG) G. Kotteeswari and P. N. Sudha* PG and Research Department of Chemistry, D. K. M College for Women, Vellore, Tamilnadu, India

Chitosan oligosaccharide biopolymer has outstanding advantages over chitin and chitosan. It is water soluble, non-toxic, biocompatible and offer possibilities of chemical modifications for various applications. In this present study chitosan oligosaccharide is modified as chitosan oligosaccharide – g – maleic anhydride – g – acryl amide / poly propylene glycol blend. The prepared blend was analysed using FTIR, XRD, TGA, DSC and SEM analysis. Batch adsorption studies were carried out to find the adsorption efficiency of the material prepared by varying the parameters such as adsorbent dose, contact time, pH and initial concentration of the metal solution. The results are fitted with Langmuir and Freundlich isotherm models. Desorption studies were done by varying contact time.

Key words: Chitosan oligosaccharide, maleic anhydride, acrylamide, poly propylene glycol, blending, adsorption, desorption, Langmuir and Freundlich isotherms.

References 1. Vilela, P.B.; Dalalibera, A.; Duminelli, E.C.; Becegato, V.A.; Paulino, A.T. Environ Sci Pollut Res Int. 2019, 26(28), 28481-28489. 2. Vusumzi, E.P.; Nikita, T.T.; Lawrence, M.M. RSC Advances, 2019, 45.

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P134 Enhancing cell penetration and proliferation in Nanochitosan /Silk Fibroin binary Scaffolds Using MC3T3-E1 Cell Line for tissue engineering applications

S. Gokila, T. Gomathi, Anil Sukumaran and P.N. Sudha* Biomaterials Research Lab, Department of Chemistry, D.K.M. College for Women, Vellore, TamilNadu, India.

NanoChitosan /Silk-Fibroin of binary scaffold was prepared and chemically crosslinked were geared up by the simple ionic cross linking method using TPP to get better bioavailability . Thermal and morphological studies were performed for the prepared binary scaffolds. Characterizations of the binary scaffold were investigated by thermo gravimetric analysis (TGA), differential calorimetry (DSC). TGA and DSC studies reveal that the thermal stability of the blend is enhanced to carry out biomedical applications. In-vitro cell culture study using MC3T3-E1 cells has shown an enhanced cell attachment, proliferation and differentiation. An enhanced scaffold porosity, hydrophilicity, cell adhesion and cell proliferation were further achieved by the incorporation of the binary Scaffolds NCS/SF. Some of the assays studied in the cell line- MC3T3-E1 include, ALP and Fluorescent Assay. Antimicrobial studies were also done and sample has the potential to kill the microorganisms to a greater extent. In addition to biocompatibility and satisfactory cell affinity, this material will have great potential applications in the field of bone tissue engineering. In the near future, it is most likely that the NCS/SF scaffold based systems would help to reconcile the clinical and commercial demands in tissue engineering.

Keywords: silk fibroin, Nanochitosan, biomaterial, scaffolds, cell culture, in vitro studies.

References Sangeethaa, V; Sudha, P.N; gomathi, T ; jayaprabakar, J, Journal of Nanomaterials and Biostructures. 2019, 14, 963-972.

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P135 Removal of Toxic Heavy Metal Chromium Using Nanochitosan/Carboxymethylcellulose/Graphene Oxide Nano Composite S. Sugashini and P.N. Sudha* Biomaterials Research Lab, Department of Chemistry, DKM College for Women (Autonomous), Vellore, India The removal of heavy metals from wastewater is essential to avoid pollution. In the present work ternary Nanochitosan(NC)/Carboxymethyl cellulose (CMC)/ Graphene Oxide(GO) nanocomposite was used under different experimental conditions for the removal of Chromium from water. Advanced analytical techniques such as FT-IR, XRD, TGA and DSC were used to study the physicochemical properties of the composite. The Batch adsorption studies were conducted using the prepared ternary nanocomposite by varying the parameters such as pH, adsorbent dosage, contact time and initial Cr(VI) ion concentration. The adsorption data has been used to explain the kinetic model, Langmuir and Freundlich isotherm equations. From the results it is proved that NC/CMC/GO nanocomposite was formed and can be used as a promising material for treating industrial effluents.

Keywords: Nanochitosan, Carboxymethyl cellulose, Graphene oxide, Nanocomposite chromium (VI) adsorption.

Reference: 1. Leonard, A,; Lauwerys, R.R, Mutat. Res. 1980, 76,227-239. 2. Langard, S. Biological and environmental Aspects of Chromium. McGraw Hill Book Co., Inc, New York. 1893, 314.

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P136. Removal of Cr (VI) from Aqueous Solution using Orange Peel-based Biosorbents S. Pavithra and P.N. Sudha* Biomaterials Research Lab, Department of Chemistry, DKM College for Women (Autonomous), Vellore, India.

Now-a-days, adsorption has been recognized as an effective method to remove heavy metals ions in water sources. Chromium is a considerable environmental concern as it is widely used in leather tanning, electroplating, metal finishing and chromate preparation. Chromium occurs in aqueous environment in trivalent and hexavalent forms. Hexavalent chromium is more toxic than the trivalent form because of its carcinogenic and mutagenic effects. During the last decade, hydrogels have been used as potential adsorbents for removal of contaminants from aqueous solution. A novel hydrogel based on the orange peel (OP) and chitosan was prepared by solgel method. This work is focused on studying removal of chromium (VI) from aqueous solution by orange peel-based adsorbents (OP, OP-Chitosan). Effects of pH and adsorbent dosage on the adsorption of Cr (VI) were evaluated in order to determine suitable conditions for carrying out adsorption process. The prepared hydrogel was characterized using various analytical techniques such as FT-IR, XRD, Thermal studies (TGA and DSC) studies. The swelling behaviour was determined as a function of swelling time. The developed hydrogel was used for the removal of Cr6+ from synthetic water. Keywords: Adsorption, Biosorbent, Chromium, Orange peel, Chitosan. References 1. Tejada-Tovar, C; Gonzalez-Delgado, A.D; and Villabona-Ortiz, A, Indian Journal of Science and Technology 2018, 11(13). 2. Jisha, T.J; Lubna, C.H; Habeeba, V; IJARIIE 2017, 3(4).

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P137 Synthesis, characterization and biomedical applications of chitosan and carboxymethyl chitosan – salicylaldehyde cobalt complexes C. Mujeebur Rahman and M. S. Dastageer* Department of Chemistry, C. Abdul Hakeem College, Melvisharam, Vellore, Tamil Nadu, India

The present study was aimed to carry out by synthesizing new chitosan and carboxymethyl chitosan Schiff bases using salicylaldehyde to investigate their efficiency and to study their activity for biomedical application. These Schiff bases are then complexed with the transition metals such as cobalt and these novel derivatives were characterized to analyse their formation, thermal stability and its physical state, through FTIR, TGA, DSC and XRD. FTIR spectral analysis showed characteristic bands confirming the Schiff base formation and its metal complexes which are coordinated to the Schiff base ligands. The characteristic peaks in the range of 1600 - 1680 cm-1 confirms the presence of the C=N imine linkage and aromatic C=C group. The thermogram results revealed that there was a change in thermal behaviour in all the Schiff base polymers and their complexes. From the XRD investigations it could be found out that the derivatives showed poor crystallinity. In vitro antimicrobial studies and cytotoxicity studies were carried out for the prepared derivatives to study its suitability for biomedical applications. The results revealed that the materials had an appropriate surface for the sequential responses, which are essential for cell survival and function. Keywords: Schiff base complexes, Chitosan, Carboxymethyl chitosan, Biomedical application

References: 1. Joydeep Dutta; Pradip Kumar Dutta. In Chitin, Citosan, Ologosaccharides and their Derivatives. Biological Applications. Ed. Se-Kwon Kim. CRC Press. 2010, 195-214. 2. Keegan, G.M.; Learmonth, I.D.; Case, C. Crit. Revs. Toxicology. 2008, 38, 645-674.

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P 138. Wound healing applications of biosilica/silk fibrion/polyurethane foam blend P. Supriya Prasad and M. Deepa* Department of Chemistry, Muthurangam Government Arts College, Vellore, Tamil Nadu, India (*Corresponding author: Email:

Biosilica based material have a good application in the biomedical field, especially in would healing application. Microbial contamination in wounds leading to severe sepsis can be treated with antiseptics and frequent treatment with antiseptics leads to staining of skin, burning, and irritation at the application site. Thus, the present was aimed to formulate biosilica/silk fibrion/polyurethane foam blend with antimicrobial properties for accelerated wound healing. The prepared wound dressing material was characterized using Fourier transform infrared spectroscopy for its formation. The suitability of the material was evaluated by antimicrobial studies and the results revealed that biosilica/silk fibrion/polyurethane foam blend have higher bactericidal activity. The in vivo animal tests were employed to confirm the biocompatibility of the blend as wound-dressing application. An in vivo model revealed that biosilica/silk fibrion/polyurethane foam blend had superior wound closure as supported by results of histopathology. Based on the results, biosilica/silk fibrion/polyurethane foam blend will become a promising biomaterial for wound dressing application. Keywords: Biosilica, polyurethane foam, wound healing application

References: 1. Yuvarani, I.; Sunil Jai Kumar; Jayachandran Venkatesan; Se-kwon Kim; Sudha, P.N. Materials Science, 2012, 10.1166/jbt.2012.1037

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P139. Bactericidal effect of Murraya Koenigii sparg leaf extract modified CaO nanoparticles S. Ananda, P. N. Sudhab, R. Arunadevi*b, aEntomology Research Institute, Loyola College, Chennai-600034, Tamil Nadu, India. bDepartment of Chemistry, D. K. M. College for Women (Autonomous), Vellore-632001, Tamilnadu, India.

With an increase in antibiotic resistance, a growing interest in developing new antimicrobial agents has gained popularity. Metal-and metal-oxide-based nanoparticles, surface-to-volume is able to distinguish bacterial cells from mammalian cells and can provide long-term antibacterial activity. CaO nanoparticles were synthesized using Murraya Koenigii sparg leaf extract by biogenic method. The products were characterized by Scanning electron microscope (SEM), Ultra violet visible diffuse reflectance spectra (UV-vis-DRS), energy dispersive X-ray spectroscopy (EDX), photoluminescence spectroscopy (PL) and x-ray diffraction (XRD) techniques. The band gap were observed to be 5.67 and 5.3 eV, CaO and Murraya Koenigii sparg (MKCA) leaf extract modified CaO respectively. The results of SEM revealed that development of MKCA nanoparticles have flake with plate like morphology. We used these nanomaterials to evaluate their antibacterial activity against both Gram- negative and Gram-positive bacteria.

Figure: SEM image of MKCA

References:

1. Arunadevi, R.; Kavitha, B.; Rajarajan, M.; Suganthi, A.; Jeyamurugan, A.; Surfaces and Interfaces, 2018, 10, 32–44. 2. Gajjar, P.; Pettee, B.; Britt, DW.; Huang, W.; Johnson, WP.; Anderson, AJ.; J Biol Eng. 2009, 3 (9), 1-13.

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P140 Chemical modification of Chitosan Oligosaccharide derivatives for the Removal of Cadmium(II) ions from aqueous solution. E.Radha and P.N.Sudha* Biomaterial Research lab, PG & Research Department of Chemistry, D.K.M. College for Women, Vellore, Tamilnadu, India

To develop low-cost and environmentally responsive polymeric materials for enrichment, remediation of metal ions from aqueous solution, novel reactive graft copolymers based on Chitosan Oligosaccharide were synthesized by grafting and blending process. Structural aspects of graft copolymers have been characterized by FTIR, XRD, TGA and SEM analysis. The sorption capacity was brought under batch mode to suit the optimal parameter viz., initial concentration, adsorbent dose, pH, and agitation time which influences the sorption. Experimental data were analyzed by Langmuir, Freundlich and Temkin adsorption isotherms. The isotherm study revealed that the equilibrium adsorption is well-fitted to the Freundlich isotherm. The adsorbed sample was characterized by SEM –EDAX and FTIR analysis, which confirmed that interaction between adsorbate and adsorbent took place effectively. The metal loaded sorbent was taken for desorption studies. The desorption kinetic studies showed that the desorption process follows pseudo second order kinetics.

Keywords: Chitosan oligosaccharide(COS), Grafting, Blending, Adsorption, Desorption

References 1 Sun, T; Hu, D.M; Xie, J, Natural Product Research and Development, 2012, 164-167, 190. 2 Prakash, N; Sudha, P.N; Renganathan, N.G, 2012, Environ. Sci.Pollut. Res. 19, 2930–2941.

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