DOCSLIB.ORG

On the Syntheses and Reactions of Boroles and Boraindenes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
On the Syntheses and Reactions of Boroles and Boraindenes University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2014-10-08 On the Syntheses and Reactions of Boroles and Boraindenes Houghton, Adrian Yuri Houghton, A. Y. (2014). On the Syntheses and Reactions of Boroles and Boraindenes (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/27197 http://hdl.handle.net/11023/1925 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY On the Syntheses and Reactions of Boroles and Boraindenes by Adrian Yuri Houghton A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Department of Chemistry CALGARY, ALBERTA September, 2014 © ADRIAN YURI HOUGHTON 2014 Abstract Highly Lewis-acidic boranes are an important class of compounds in both fundamental and applied chemistry. Recently, a sub-class of boranes known as boroles – five-membered unsaturated boracycles – has begun to receive attention due to the interesting properties afforded by the anti-aromatic nature of these compounds. We synthesized and characterized a new class of boroles wherein the borole ring is fused to a benzene ring. These “boraindenes” were found to be highly Lewis acidic by the Gutmann- Beckett method, even more so than the ubiquitous tris-pentafluorophenylborane. Structural and computational evidence supports the notion that these compounds are anti-aromatic, which likely contributes to their Lewis acidity. A series of six derivatives was synthesized, and it was found that they had only marginally different absorption spectra. Previous work in our group showed that perproteo and perfluoro-pentaphenylboroles are capable of irreversibly activating dihydrogen. The mechanism of this reaction was investigated both experimentally and computationally, and it was found that the reaction was bimolecular in nature. Furthermore, the reaction involves the formation of a transient dihydrogen-borole adduct which quickly adds dihydrogen across the boron-carbon bond. A 1,2-hydride shift can lead to a cisoid product, and cleavage of the boron-carbon bond results in a ring-opened intermediate that ultimately rearranges to give the transoid product; independent synthesis of this ring-opened intermediate confirms that it does indeed give the transoid product. The most Lewis acidic of the boraindenes, perfluoro-1,2,3-triphenyl-1-boraindene, appears to react reversibly with dihydrogen gas. This compound has proven capable of ii mediating the hydrogenation of cyclohexene, though its precise role remains obscured in part due to the fact that it reacts with cyclohexene itself. Perfluoro-1,2,3-triphenyl-1-boraindene was found to reversibly form an adduct with triethylsilane in solution, an adduct that was also isolated in the solid state. The solution-phase equilibrium was characterized by a titration followed by nuclear magnetic resonance spectroscopy, which revealed that the equilibrium is nearly thermoneutral at room temperature but favours adduct formation at lower temperatures. Infrared spectroscopy and X-ray diffraction analysis on solid samples confirm that the adduct is formed via a three-centre, two-electron silicon-hydrogen-boron bonding interaction. Perfluoro-1,2,3-triphenyl-1-boraindene was also found to be an active catalyst for the hydrosilation of olefins. iii Acknowledgements This doctoral thesis represents the culmination of five years of hard work, and I would be remiss were I not to acknowledge all those who aided me throughout this endeavour. First and foremost I would like to thank my supervisor Professor Warren Edward Piers, without whom none of this would have been possible. His keen insights and intense dedication are aspects I have tried to incorporate into myself, and working in his group has moulded me into the scientist that I am today. I would like to thank the members of my supervisory committee, Dr. Todd Sutherland and Dr. Thomas Baumgartner, for their additional support throughout my degree. I would also like to thank the other members of my examination committee, Dr. Peter Tieleman and Dr. T. Don Tilley, for taking the time to evaluate my thesis. Gratitude is extended to Dr. Roland Roesler and Dr. David Schriemer for serving on my candidacy committee. All the members of the Piers group, past and present, have helped me in some way or another, whether it be through showing me a new technique, discussing experiments or teaching me something new. I would like to thank Master Juan Felipe Araneda in particular, who has been a fellow boron chemist from the beginning, for his help, friendship, and aid in maintaining the air- and moisture- free working paradise that is the Boron Box. In addition to his help in the lab, Dr. Francis A. Leblanc introduced me to Crossfit and helped me get into some of the best shape in my life. I would also like to thank Dr. Tracy Griffin (Lohr), Dr. Rich Burford, Master Terry Chu, Dr. Lauren Mercier, Dr. Adam Marwitz, Dr. Andrey Khaliman, Dr. Dmitry Gutsulyak, Dr. Erin Leitao, Dr. Thomas Wood, Dr. Matt Sloan, Dr. Andreas Berkefeldt, Dr. Benedikt Neue and Dr. Cheng Fan. iv There are a number of people to whom I owe thanks for the development of my abilities as a crystallographer (if I can presume to call myself one). Dr. Masood Parvez taught me the principles of crystallography and showed me how to use the instruments, and I have received additional support from Doctors Javier Borau-Garcia, Jason Dutton, Michael Sgro, and Denis Spasyuk. The instrumentation staff at the University of Calgary provide and maintain the excellent facilities that make much of our work possible. Dr. Michelle Forgeron has done an excellent job of leading her team while also providing support to our lab during the move. Qiao Wu, Wade White, Dorothy Fox and Jian Jun Li have also been incredibly helpful and pleasant to work with. Additional support from around the department has been exemplary. Mark Toonen is a truly gifted and hard-working glassblower without whom I would likely be graduating much later. The machine shops and electrical shops have been instrumental in keeping our lab functioning, and I would like to thank them all for their efforts. Bonnie King and Janice Crawford have been a great help keeping me on track and aiding in scholarship applications, for which I am very grateful. My parents, Dean and Anne Houghton, have been unwaveringly loving and supportive throughout my entire life. My little sister Vanessa has been an excellent friend and confidante, of whom I am very proud. I am happy to have had them so close throughout this degree, for they have surely made it easier. My friends, both within and outside the department, have each certainly made things more fun and enjoyable than if they had been absent during this time in my life. Dustin Pearson kept me going to the gym in the mornings for two years and I am stronger because of it. I would v like especially to thank Ryan Bebb, Leah Kilvert and Mari Boesen. I would also like to offer a heartfelt thanks to the Burner community as a whole, for showing me just how rad life can be. vi Table of Contents Abstract............................................................................................................................... ii Acknowledgements............................................................................................................ iv Table of Contents.............................................................................................................. vii List of Tables ...................................................................................................................... x List of Figures.................................................................................................................. xiv List of Schemes.............................................................................................................. xviii List of Symbols, Abbreviations and Nomenclature......................................................... xxi List of Numbered Compounds in Chapters 1 and 2....................................................... xxvi List of Numbered Compounds in Chapters 3 and 4...................................................... xxvii List of Numbered Compounds in Chapter 5................................................................ xxviii List of Numbered Intermediates .................................................................................. xxviii CHAPTER ONE: INTRODUCTION.........................................................................................................1 1.1 Lewis Acids and Bases ............................................................................................. 1 1.2 Lewis Acidity Scales ................................................................................................ 5 1.3 Applications of Boron Lewis Acids.......................................................................... 8 1.4 Boroles .................................................................................................................... 14 1.4.1 Aromaticity and Anti-aromaticity .................................................................
Load more

Recommended publications
  • A Germaaluminocene†
    Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue A germaaluminocene† Cite this: Chem. Sci., 2020, 11, 2982 Lena Albers, * Patrik Tholen, Marc Schmidtmann and Thomas Muller¨ * All publication charges for this article The reactions of dipotassium germacyclopentadienediide with two Group 13 dichlorides, Cp*BCl and have been paid for by the Royal Society 2 * ff of Chemistry Cp AlCl2, yield two structurally di erent products. In the case of boron a borole complex of germanium(II) is obtained. The aluminium halide gives an unprecedented neutral Received 21st January 2020 Accepted 7th February 2020 germaaluminocene. Both compounds were fully characterised by multinuclear NMR spectroscopy supported by DFT computations. The molecular structure of the germaaluminocene was DOI: 10.1039/d0sc00401d determined by XRD. rsc.li/chemical-science Introduction conversion and aer work-up complex 2c was isolated as a brown oil in 35% yield (Scheme 2). NMR spectroscopy evi- The aim of utilizing readily available and environmentally denced the presence of the expected borole ring with a h1- benign main group element compounds for activation of bound cyclopentadienyl substituent. Interestingly, the NMR Creative Commons Attribution-NonCommercial 3.0 Unported Licence. unreactive materials and strong bonds instead of transition data indicated frozen rotation around the B-Ca single bond, metal-based complexes became increasingly popular during the giving rise to ten 13C NMR signals for the cyclopentadienyl last decade.1 We attempted to follow this lead by establishing substituent (Table S3, ESI†). In addition, all four carbon atoms polarised heteroalkenes I as they mimic the electronic situation of the borole ring are magnetically non-equivalent.
    [Show full text]
  • Parallels to Frustrated Lewis/Radical Pair Chemistry
    klh00 | ACSJCA | JCA11.2.5208/W Library-x64 | manuscript.3f (R5.0.i3:5004 | 2.1) 2020/02/05 13:43:00 | PROD-WS-121 | rq_481292 | 7/01/2020 12:12:45 | 10 | JCA-DEFAULT pubs.acs.org/IC Article 1 Redox-Controlled Reactivity at Boron: Parallels to Frustrated Lewis/ 2 Radical Pair Chemistry ⊥ ⊥ 3 Anthony Wong, Jiaxiang Chu, Guang Wu, Joshua Telser, Roman Dobrovetsky, and Gabriel Menard́ * Cite This: https://dx.doi.org/10.1021/acs.inorgchem.0c01464 Read Online ACCESS Metrics & More Article Recommendations *sı Supporting Information 4 ABSTRACT: We report the synthesis of new Lewis-acidic boranes μ 5 tethered to redox-active vanadium centers, (Ph2N)3V( -N)B(C6F5)2 μ 6 (1a)and(N(CH2CH2N(C6F5))3)V( -N)B(C6F5)2 (1b). Redox IV/V 7 control of the V couple resulted in switchable borane versus 8 “hidden” boron radical reactivity, mimicking frustrated Lewis versus 9 frustrated radical pair (FLP/FRP) chemistry, respectively. Whereas V 10 heterolytic FLP-type addition reactions were observed with the V 11 complex (1b) in the presence of a bulky phosphine, homolytic peroxide, IV 12 or Sn−hydride, bond cleavage reactions were observed with the V * μ 13 complex, [CoCp2 ][(N(CH2CH2N(C6F5))3)V( -N)B(C6F5)2](3b), 14 indicative of boron radical anion character. The extent of radical 15 character was probed by spectroscopic and computational means. IV/V 16 Together, these results demonstrate that control of the V oxidation 17 states allows these compounds to access reactivity observed in both FLP 18 and FRP chemistry.
    [Show full text]
  • Pentamethylcyclopentadienyl Aminoborole Complexes of Hafnium
    Pentamethylcyclopentadienyl Aminoborole Complexes of Hafnium Thesis by Andrew F. Kiely In Partial Fufillment of the Requirements for the Degree of Doctor of Philosophy Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena, California 1997 (Submitted August 20,1996) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. For M y Parents Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. iii Acknowledgments First and most importantly, I would like to thank John Bercaw for the support, encouragement, and opportunities that he has given me over the course of my studies at Caltech. I have been very fortunate to have been able to learn chemistry from someone who is a fine and generous person as well as a great scientist, and I am very grateful to him. I am also grateful to Bill Schaefer, Larry Henling, and Mike Day for performing all the crystallographic work that is reported in this thesis. I appreciate all their good humor and patience despite my (occasional) impatience and (more occasional) ignorance. I've really enjoyed hiking with Bill and playing outfield with Larry as well. The students and post-docs in the Bercaw group have been friends as well as coworkers. Over the years, people in the Bercaw group have been generous with their time, advice and friendship. When I was getting started in the group, Donny Cotter, Bryan Coughlin, and Roger Quan were never too busy to answer my questions or to set me straight. I'm especially grateful to Roger, who helped me to learn vacuum line techniques when I was starting on the aminoborole project.
    [Show full text]
  • The Water-Energy Nexus: Challenges and Opportunities Overview
    U.S. Department of Energy The Water-Energy Nexus: Challenges and Opportunities JUNE 2014 THIS PAGE INTENTIONALLY BLANK Table of Contents Foreword ................................................................................................................................................................... i Acknowledgements ............................................................................................................................................. iii Executive Summary.............................................................................................................................................. v Chapter 1. Introduction ...................................................................................................................................... 1 1.1 Background ................................................................................................................................................. 1 1.2 DOE’s Motivation and Role .................................................................................................................... 3 1.3 The DOE Approach ................................................................................................................................... 4 1.4 Opportunities ............................................................................................................................................. 4 References ..........................................................................................................................................................
    [Show full text]
  • Sulfur Bonded Unsymmetrical Borole Complexes: Synthetic, Spectroscopic and Biocidal Aspects
    SULFUR BONDED UNSYMMETRICAL BOROLE COMPLEXES: SYNTHETIC, SPECTROSCOPIC AND BIOCIDAL ASPECTS Taruna Pandey1, V. P. Singh2 and R. V. Singh1* 1 Department of Chemistry, University of Rajasthan, Jaipur-302004, India 2 DSME, S.C.E.R.T., Varun Marg, Defence Colony, New Delhi-110024, India ABSTRACT Synthesis, characterization and biological activities of some of the unsymmetrical borole complexes containing B-S and B<-N bonds are described. The sulfur containing conjugated bases were prepared by the condensation of caibonyl compounds with thiosemicarbazide. The resulting complexes have been characterized by elemental analysis, molecular weight determinations and spectral studies including IR, Ή NMR, "Β NMR and ,3C NMR. The spectroscopic results showed that the conjugated bases behave in a bidentate fashion, whereas, the complexes display a tetracoordinated environment around the boron atom as steriochemically active lone pair is also included in the coordinated sphere. The conjugated bases and their respective boron complexes have been screened for their antifungal and antibacterial properties. INTRODUCTION Recently, few references on bidentate ligands coordinated to boron through the azomethine nitrogen and the thiolo sulfur have been published in the literature1·2. These compounds are interesting in many respects. Some have got a number of applications in industry, biology and agriculture. Industrial applications of coordination compounds of boron have remained fairly limited. Boron analogues of carboxylic acids and peptides have been shown to possess interesting biological activities in particular as serine protease inhibitors3. Use of boron-nitrogen compound in neutron capture therapy of brain tumors have also been investigated4. Several organoboranes find promising applications in the synthesis of insect pheromones5.
    [Show full text]
  • SYNTHESIS, CHARACTERIZATION, in VITRO and in VIVO SCREENING of UNSYMMETRICAL BOROLE COMPLEXES of 2-HYDROXY-N-PHENYLBENZAMIDE and ITS DERIVATIVES Taruna Pandey and R
    SYNTHESIS, CHARACTERIZATION, IN VITRO AND IN VIVO SCREENING OF UNSYMMETRICAL BOROLE COMPLEXES OF 2-HYDROXY-N-PHENYLBENZAMIDE AND ITS DERIVATIVES Taruna Pandey and R. V. Singh* Department of Chemistry, University of Rajasthan, Jaipur 302004, India. ABSTRACT Biochemical aspects, synthesis and characterization of some boron complexes of 2-hydroxy-N- phenylbenzamide (HOPhBenz) and its semicarbazone (HOPhBenz.SCZH) and thiosemicarbazone (HOPhBenz.TSCZH) are described. These derivatives were prepared by the reactions of 2-isopropoxy-4- methyl- 1,3,2-dioxaborolane, and 2-isopropoxy-4-methyl- 1,3,2-dioxaborinane with 2-hydroxy-N-phenyl- benzamide, 1-[(2-hydroxyphenyl)-l-N-phenylamino]hydrazinecarboxamide (HOPhBenz.SCZH), and 1-[(2- hydroxyphenyl)-l-N-phenylamino]hydrazinecarbothioamide(HOPhBenz.YSCZH) in a 1:1 molar ratio. In order to assess the increase of the inhibitor potency, (HOPhBenz), (HOPhBenz.SCZH), (HOPhBenz. TSCZH) and their boron complexes have been tested in vitro against a number of pathogenic fungi and bacteria at different concentrations and were found to possess remarkable fungicidal and bactericidal properties. The testicular sperm density, testicular sperm morphology, sperm motility, density of cauda epididymal spermatozoa and fertility in mating trials and biochemical parameters of reproductive organs are discussed. INTRODUCTION Boron chemistry has continued to provide the most novel developments in the field of coordination chemistry. Inorganic chemistry of boron is much more diverse and complex than that of any other element in the Periodic Table and this is due to the elucidation of tremendous range of bondin intractions. Several organoboranes find promising applications in the synthesis of insect pheromones'. Boron azomethine complexes of various ligands have been found to possess conspicuous biocidal activity2.
    [Show full text]
  • Planar Chiral Lewis Acids and Lewis Pairs Based On
    PLANAR CHIRAL LEWIS ACIDS AND LEWIS PAIRS BASED ON FERROCENE by JIAWEI CHEN A Dissertation submitted to the Graduate School-Newark Rutgers, The State University of New Jersey in partial fulfillment of requirements for the degree of Doctor of Philosophy Graduate Program in Chemistry written under the guidance of Professor Frieder Jäkle and approved by Newark, New Jersey May, 2014 © 2014 Jiawei Chen ALL RIGHTS RESERVED ABSTRACT OF THE DISSERTATION PLANAR CHIRAL LEWIS ACIDS AND LEWIS PAIRS BASED ON FERROCENE by Jiawei Chen Dissertation Advisor: Professor Frieder Jäkle Organoboranes have been widely used for catalytic transformations, polymerizations, small molecule activation, anion and glycol sensing and construction of electronic materials. These remarkable applications commonly benefit from the electron-deficient nature of tricoordinate boron, i.e., its empty p- orbital can accommodate a lone pair of electrons or participate in conjugation of extended π-systems. Therefore, approaches to enhance the Lewis acidity of the boron center are desirable, and different strategies have been introduced with this aim, including (1) installation of electron withdrawing pendant groups such as pentafluorophenyl groups; (2) generation of cationic borenium species and (3) incorporation of tricoordinate boron into anti-aromatic systems such as borole derivatives. Recently, much effort has been directed to the preparation of the so- called “Frustrated Lewis Pair” (FLP) and the application of their unquenched relativity for catalytic transformations. However, chiral versions of highly Lewis acidic organoboranes remain scarce. On the other hand, planar chiral ferrocenes have proven to provide rigid frameworks for transition metal ligands such as ii phosphines and amines, which have been successfully applied to the asymmetric hydrogenation of alkenes, ketones and other processes.
    [Show full text]
  • States Patent 0 " 1C@ Patented Feb
    a 3,426,052 States Patent 0 " 1C@ Patented Feb. 4, 1969 1 2 a yellow green, ?uorescence comparable to that of zinc 3,426,052 FIVE MEMBERED ZIRCONIUM, BORON, or cadmium sul?des. The ?uorescent spectrum can be THALLIUM AND GOLD HETEROCY often shifted to the corresponding oxide thereby making CLIC COMPOUNDS it possible to variably provide a ?uorescent compound and Karl W. Hubel and Emile H. Braye, Brussels, Belgium, the particular ?uorescent spectrum desired. assignors to Union Carbide Corporation, a corporation The hetero-containing compounds of this invention also of New York behave as dienes and can, therefore, be involved in Diels No Drawing. Continuation-in-part of application Ser. No. Alder reactions. For example, the reaction of pentaphenyl 18,805, Mar. 31, 1960. This application June 15, 1960, phosphole with the dimethyl ester of acetylene dicar Ser. No. 36,132 Claims priority, application Great Britain, Apr. 7, 1959, boxylic acid yields the dimethyl ester of tetraphenyl 11,679/59 phthalic acid in almost quantitative amounts. A normal U.S. Cl. 260—429 7 Claims adduct is also obtained by Diels-Alder addition with Int. 'Cl. C07f 1/12, 7/00, 5/02 maleic .anhydride. Another general use for the metal containing com~ This invention relates to novel organic compounds and 15 pounds prepared by the process of this invention is as more particularly to novel ?ve-membered heterocyclic anti-knock additives in motor fuels either alone or in compounds. conjunction with other organo-metallic compounds. They This application is a continuation-in-part of our co could also be used as metal-plating agents.
    [Show full text]
  • A Computational Study on a Strategy for Isolating a Stable Cyclopentadienyl Cation
    DOI: 10.1002/chem.201xxxxxx █ Stabilized cyclopentadienyl cation A computational study on a strategy for isolating a stable cyclopentadienyl cation Kalon J. Iversen, David J. D. Wilson*[a] and Jason L. Dutton*[a] Abstract: A computational study has been carried out to derivative that may approach the stability of isolobal (and examine the feasibility of generating a simple monocyclic isolatable) borole rings, as evaluated by HOMO-LUMO and cyclopentadienyl cation that may be sufficiently stable to singlet-triplet gaps. These Cp+ derivatives may therefore be an isolate and handle at ambient temperatures. Using judicious attractive target for synthetic isolation. placement of electron withdrawing groups (CF3) about the ring we have identified a Introduction The isolobal neutral boron centred analogues (boroles) have recently experienced a resurgence of interest.[12] The + + [13] The antiaromatic cyclopentadienyl cation ([C5H5] ; [Cp] ; 1) has pentaphenyl borole ring (4) was reported some time ago, but long fascinated synthetic and theoretical chemists alike. The the determination of the solid state structure by Braunschweig in parent cation 1, has a triplet ground state and has been observed 2008 led to a substantial increase in activity.[14] Piers reported the at low temperatures via EPR studies, as have several substituted perfluorinated analogue (5) shortly thereafter.[15] These [1-3] analogues. However, as yet no isolatable monocyclic species compounds are indefinitely stable when stored under N2 or Ar and has been reported. The instability of the cation can be both species have demonstrated unusual and interesting [16-17] [18-22] rationalized from simple Hückel theory, where a 4- electron reactivity, such as H2 activation, reduction chemistry, triplet diradical is predicted (Figure 1).
    [Show full text]
  • 1 Full List of Publications – Prof. Holger Braunschweig 29.11.2019
    Full List of Publications – Prof. Holger Braunschweig 29.11.2019 2019 [560] Z.-F. Jiao, Y.-M. Tian, B. Zhang, C.-H. Hao, Y. Qiao, Y.-X. Wang, Y. Qin, U. Radius, H. Braunschweig, T. B. Marder, X.-N. Guo, X.-Y. Guo High Photocatalytic Activity of a NiO Nanodot-decorated Pd/SiC Catalyst for the Suzuki- Miyaura Cross-coupling of Aryl Bromides and Chlorides in Air submitted. [559] I. Krummenacher, J. K. Schuster, H. Braunschweig Synthesis and Reactivity of Bora- and Boratabenzenes in Patai’s Chemistry of Functional Groups (Eds. Ilan Marek and Mark Gandelman) 2019, DOI:10.1002/9780470682531.PAT0969 in press. [558] W. C. Ewing, T. Dellermann, Y. T. A. Wong, J. D. Mattock, A. Vargas, D. L. Bryce, H. Braunschweig Metal-free π-Complexes Between Diborynes and Main Group Atoms submitted. [557] F. Rauch, S. Fuchs, A. Friedrich, D. Sieh, I. Krummenacher, H. Braunschweig, M. Finze, T. B. Marder Having your cake and eating it too: highly stable, readily reducible, fluorescent, trifluoromethylated 9-borafluorenes submitted. [556] T. Thiess, M. Ernst, T. Kupfer,H. Braunschweig 1,4-Diaza-2,3-diborinines – Synthesis and Functionalization submitted. [555] D. Prieschl, G. Bélanger-Chabot, X. Guo, M. Dietz, M. Müller, I. Krummenacher, Z. Lin, H. Braunschweig Synthesis of Complex Boron-Nitrogen Heterocycles Comprising Borylated Triazenes and Tetrazenes Under Mild Conditions submitted. [554] G. Horrer, M. J. Krahfuß, K. Lubitz, I. Krummenacher, H. Braunschweig, U. Radius, N-Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbine Complexes of Titanium(IV) and Titanium(III) submited. [553] J. H. Muessig, P. Lisinetskaya, R. D. Dewhurst, R.
    [Show full text]
  • Unsymmetrical Borole Complexes of Monobasic Bidentate Benzothiazolines
    UNSYMMETRICAL BOROLE COMPLEXES OF MONOBASIC BIDENTATE BENZOTHIAZOLINES Taruna Pandey and R. V. Singh* Department of Chemistry, University of Rajasthan, Jaipur - 302004, India ABSTRACT The synthetic spectroscopic and biological studies of some unsymmetrical borole complexes derived from heterocyclic ketones and 2-mercaptoaniline have been characterized on the basis of elemental analysis molecular weight determinations and spectral studies including IR, !H NMR, 13C NMR and nB NMR. The equimolar reaction between unsymmetrical borole and these benzothiazolines have produced [B(C3H<;02) (N^S)] and [B^HgO^ (N°S)] type of boron complexes. The spectroscopic results show that the benzothiazolines behave in a monobasic bidentate fashion rendering the non-metal tetracoordinated. The benzothiazolines and their respective non-metal complexes have been screened for their antifungal and antibacterial properties. INTRODUCTION Boron and its compounds have attracted the attention of a large number of chemists mainly because of the tremendous range of structural peculiarities and subtle types of bonding. Boron shows an astonishing number of structural polymorphs. Further, the synthetic flexibility of boron, which has a wide range of 'applications in various disciplines, has attracted a number of investigators in the field. Arene boronic acids show antiserotonin activity1. The toxicity to mice of a number of triarylboranes and their amine complexes has been investigated2. Recently, interest has also been sustained in the structural aspects of compounds containing boron - nitrogen bonds3"7. Benzothiazolines, which are biologically very active, constitute an important class of nitrogen and sulphur donor ligands8"9. The inherent biological potential of sulphur donor ligands prompted us to prepare unsymmetrical borole complexes of benzothiazolines.
    [Show full text]
  • Review in Heterocyclic Compounds 51
    Journal of Plastic and Polymer Technology (JPPT) Vol. 1, Issue 1, Jun 2015, 49-64 © TJPRC Pvt. Ltd. REVIEW PAPER IN HETEROCYCLIC COMPOUNDS NAGHAM MAHMOOD ALJAMALI Organic Chemistry, Chemistry Department, College of Education ABSTRACT In this review paper, information about heterocyclic compounds, methods of synthesis, reactions , properties , stability, saturated and unsaturated cycles , aliphatic and aromatic cycles have been thoroughly reviewed and discussed. KEYWORDS : Heterocyclic, Three Membered, Seven, Cyclization, Sulfur,Nitrogen INTRODUCTION Three Membered Rings Heterocycles with three atoms in the ring are more reactive because of ring strain. Those containing one heteroatom are, in general, stable. Those with two heteroatoms are more likely to occur as reactive intermediates. Table 1: Common 3-Membered Heterocycles with One Heteroatom Are Heteroatom Saturated Unsaturated Nitrogen Aziridine Azirine Oxygen Oxirane (ethylene oxide, epoxides) Oxirene Sulfur Thiirane (episulfides) Thiirene Tabli 2: Those with Two Heteroatoms Include Heteroatom Saturated Unsaturated Nitrogen Diazirine Nitrogen/oxygen Oxaziridine Oxygen Dioxirane MEMBERED RINGS Table 3: Compounds with One Heteroatom Heteroatom Saturated Unsaturated Nitrogen Azetidine Azete Oxygen Oxetane Oxete Sulfur Thietane Thiete Table 4: Compounds with Two Heteroatoms Heteroatom Saturated Unsaturated Nitrogen Diazetidine Oxygen Dioxetane Dioxete Sulfur Dithietane Dithiete www.tjprc.org [email protected] 50 Nagham Mahmood Aljamali MEMBERED RINGS With heterocycles containing five
    [Show full text]