DOCSLIB.ORG

Triazene (H2NNNH) Or Triimide (HNHNNH) Markofçrstel,[A, D] Yetsedaw A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Triazene (H2NNNH) Or Triimide (HNHNNH) Markofçrstel,[A, D] Yetsedaw A DOI:10.1002/cphc.201600414 Articles On the Formation of N3H3 Isomers in Irradiated Ammonia Bearing Ices:Triazene (H2NNNH) or Triimide (HNHNNH) MarkoFçrstel,[a, d] Yetsedaw A. Tsegaw,[b] Pavlo Maksyutenko,[a, d] Alexander M. Mebel,[c] Wolfram Sander,[b] and Ralf I. Kaiser*[a, d] The remarkable versatility of triazenesinsynthesis, polymer theoretical studies with our novel detection scheme of photo- chemistry and pharmacology has led to numerousexperimen- ionization-driven reflectron time-of-flight mass spectroscopy tal and theoretical studies.Surprisingly,only very little is we can obtain information on the isomersoftriazene formed known aboutthe most fundamental triazene:the parentmole- in the films. Using isotopically labeled starting material, we can cule with the chemical formula N3H3.Here we observe molecu- additionally gain insightinthe formation pathways of the iso- lar,isolated N3H3 in the gas phase after it sublimes from ener- mers of N3H3 under investigation and identify the isomers getically processed ammonia and nitrogen films. Combining formedastriazene (H2NNNH) andpossibly triimide(HNHNNH). 1. Introduction During the last decades, triazenes—a class of organic mole- life time of at least 1mswas also inferred as an intermediate cules carrying the =N N=N moiety—have received substan- in the radiolysis of an aqueous solution of hydrazine based on À À tial attention both from the theoretical and organic chemistry asingle absorption feature at 230 nm.[6] The cyclic isomer of [1] communities. Derived from cis-and trans-triazene (HN=NNH2 ; triazene, cyclotriazane, was first reported crystallographically in Scheme1), the substituted counterparts have significant appli- zeolite A, where it was stabilized by asilver cation as [1a,c] [1d] + [7] + cations in synthetic chemistry, polymer science, and phar- Ag(N3H3) . Finally,lithium-ion-complexed speciesLi(N3H3) of macology as antitumordrugs such as Dacarbazine, Temozolo- unknown structures were generated in amicrowavedischarge mide, and Mitozolomide[2] with their biological activity attribut- of hydrazine–helium mixtures.[8] ed to their purported capability to alkylate deoxyribonucleic The aforementioned spuriousindication of “triazene” iso- [3] acid (DNA). Althoughtriazenes have been synthesized for mers (N3H3)triggered significant computational efforts span- over 65 years, their stem compound[4] trans-and cis-triazene ning three decades.[9] An early study by Nguyen et al. identified (Scheme 1) could not be isolatedsince triazene undergoes a cis-and trans isomer of triazene (HN=NNH2)with all six [5] facile acid-catalyzed decomposition. An unknownisomer of atoms arranged in the same plane (Cs symmetry);the trans 1 N3H3 has been detected mass spectrometrically via signalat isomer is thermodynamically more stable by 27 to 38 kJmolÀ mass-to-charge m/z=45 as atransient speciesbydischarging compared to the cis structure (Scheme 1).[9b,c] Alater study by hydrazine(N2H4); the ionization energy of the unknown isomer Magers et al. identified two additional isomersoftriazene, trii- [5a] was reported to be 9.6 0.1 eV. Triazene (N3H3)with ahalf- mide (azimine) andcyclo-triazane (triaziridine) with triimide Æ 1 about 54 to 130 kJmolÀ and cyclo-triazane about 170 to 1 [a] Dr.M.Fçrstel, Dr.P.Maksyutenko, Prof. Dr.R.I.Kaiser 190 kJmolÀ less stable than trans-triazene. Therein it was Department of Chemistry pointed out that triazeneis“not exactly planar” and that “low- University of Hawaii, 2545 McCarthy Mall temperature isolation of these species would likely succeed”.[9d] 96822 Honolulu HI (USA) [9a] E-mail:[email protected] These findings were refinedbyPye et al. 1-amino-1,1-dia- [b] Y. A. Tsegaw,Prof. Dr.W.Sander zene was first located on the potential energy surface by Salter [9e] Lehrstuhl fürOrganische Chemie II et al., who suggested that this isomer (called isotriazene in 1 Ruhr UniversitätBochum their paper) is 42 to 50 kJmolÀ lower in energy than cyclo-tria- 44780 Bochum(Germany) zane. Combined, these resultsshow that the stabilities of tria- [c] Prof. Dr.A.M.Mebel zenes decrease in the order trans-triazene, cis-triazene, triimide, Department of Chemistry and Biochemistry Florida InternationalUniversity 1-amino-1,1-diazene and cyclo-triazane (Scheme 1). 11200 SW 8thStreet, Miami, FL 33199 (USA) Here, we exploit anovel experimental approach to synthe- [d] Dr.M.Fçrstel,Dr. P. Maksyutenko, Prof. Dr.R.I.Kaiser size N3H3 in low-temperature matrices via an interaction of ion- W. M. Keck Research Laboratory in Astrochemistry izing radiation with frozenfilms containing ammonia (NH3)and University of Hawaii, 2545 McCarthy Mall nitrogen (N )along with their deuterated (ND )and 15N-labeled 96822HonoluluHI(USA) 2 3 (15N )counterparts. Upon sublimation of the newly formed Supporting Information and the ORCID identification number(s) for the 2 author(s) of this article can be found underhttp://dx.doi.org/10.1002/ molecules, N3H3 is identified for the first time via fragment-free cphc.201600414. single-photon vacuum ultraviolet (VUV) photoionizationcou- ChemPhysChem 2016, 17,2726 –2735 2726 2016 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim Articles Scheme1.Structures, ionization energies,and relativeenergies with respect to the most stable isomer of the triazene. Distances are given in ngstrom, angles in degrees. Plain and italic numbersare calculated at the B3LYP/6-311G** and CCSD(T)/6-311G** levels of theory,respectively. Ionization energiesare adiabatic values. Numbersinparenthesis in italics denote values derived with CCSD(T)/6-311G** optimized geometries. The two bottom rows show the struc- tures of the ionic species used for the calculation of the adiabatic ionization energy. pled to areflectrontime-of-flightmassspectrometer(PI- Experimental Section ReTOF-MS)[10] through its parention at mass-to-charge m/z= Ice layers with thicknesses of 600 50 nm were prepared from four 45. This observation is substantiated by the detection of its iso- Æ different gases along with their mixtures. These ices were ammonia topically labeled counterparts N3D3 (m/z=48) along with (NH ), D3-ammonia (ND ), ammonia and nitrogen (NH ,N,1:1.0 15 15 15 3 3 3 2 Æ NN2H3(m/z=46), N2NH3 (m/z= 47), and N3H3 (m/z=48), re- 0.2) and ammonia and 15N-nitrogen (NH , 15N ,1:1 0.2) with puri- 3 2 Æ spectively. ties as follows:NH3 (Matheson;99.999%), ND3 (Isotopes Inc; 15 99+%D), N2 (Matheson;99.9999%) and N2 (Cambridge Isotope ChemPhysChem 2016, 17,2726 –2735 www.chemphyschem.org 2727 2016 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim Articles Inc. 98+% 15N). The gases and/or their mixtures were introduced into the main chamber via aglass capillary array and condensed Table 1. Data applied to calculate the irradiation doseper molecule:* marks values from CASINO simulations. onto a5.5 0.2 Kcold, rhodium-coated silver wafer.The deposition Æ of each gas took about ten minutes. During the deposition, the initial kinetic energy of the electrons, Einit 5keV pressure in the main vacuum chamber increased from (5 2) 11 8 Æ irradiation current, I 15 2nA 10À torr to (3 1)10À torr.The ice thickness was monitored Æ Æ total number of electrons (3.4 0.3)1014 [11] Æ during the deposition via in situ He–Ne laser interferometry. averagekinetic energyofbackscattered electrons, 3.3 0.9 keV Using Equation (1), alaser wavelength of l=632.8 nm and refrac- Æ Ebs*(NH3 ice) [12] [13] tive indices of NH3 and N2 of 1.35 0.05 and 1.2 0.1 and an averagekinetic energyofbackscattered electrons, 3.3 0.9 keV Æ Æ Æ angle of incidence of q=48,the number of observed interference Ebs*(NH3 :N2)ice) fringes (N )can be related to the thickness (d)ofthe ice: fraction of backscattered electrons, f *(NH ice) 0.34 0.1 f bs 3 Æ fraction of backscattered electrons, f *(NH :N ice) 0.35 0.1 bs 3 2 Æ average kinetic energyoftransmitted electrons, 1.5 0.5 keV Nf l Æ 1 d 1 E *, (NH ice) ð Þ ¼ p 2 2 ð Þ trans 3 2 n sin q average kinetic energyoftransmitted electrons, 1.6 0.5 keV À Æ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi Etrans*(NH3:N2 ice) The composition of the ice mixtures was determined by relating fraction of transmitted electrons, f *(NH ice) 0.16 0.05 1 trans 3 the NH absorption features at 1092 cmÀ with avalue of 1.7 Æ 3 fraction of transmitted electrons, ftrans*(NH3 :N2 ice) 0.08 0.05 17 [14] Æ 10À cm to the ice thickness determined by interferometry.Each average penetration depth, l*(NH ice) 365 80 nm 3 Æ sample was then irradiated for 60 min with 5keV electrons at acur- average penetration depth, l*(NH3 :N2 ice) 350 80 nm Æ 3 rent of 15 2nAbyscanning the electron beam over the target density of the NH3 ice, 1 0.66 0.05 gcmÀ Æ 3 Æ 2 density of the NH :N ice, 1 0.75 0.08 gcmÀ surface of 0.9 0.1 cm at an angle of 708 with respect to the sur- 3 2 Æ Æ irradiated area, A 0.9 0.1 cm2 face normal of the substrate. The average deposited dose D per ir- Æ total number of molecules processed (7 3)1017 radiated molecule can be calculated using Equation (2): Æ dose per NH molecule, D (NH ice)1.5 0.4 eV 3 3 Æ dose per NH molecule, D (NH :N ice) 1.3 0.4 eV 3 3 2 Æ Itm dose per N molecule, D (NH :N ice)1.9 0.5 eV 2 D Einit ftransEtrans fbsEbs 2 2 3 2 Æ ð Þ ¼ eNA 1 Alð À À Þ ð Þ where I, t, m, e, NA, 1, A and Einit are the irradiation current, irradia- generated using the frequency doubled (222.6 nm) output of tion time, molecular mass of the molecule, the electron charge, adye laser (445.1 nm, Coumarin 450, Sirah, Cobra-Stretch) which Avogadro’sconstant, the density of the ice, the irradiated area of was pumped by the third harmonic of an Nd:YAG laser (355 nm).
Load more

Recommended publications
  • Durham E-Theses
    Durham E-Theses Halogenated diazines and triazines Wood, D. E. How to cite: Wood, D. E. (1978) Halogenated diazines and triazines, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/8324/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk UNIVERSITY OF Du'RKAM A THESIS entitled HALOGENATED DIAZINES AND TRIAZINES Submitted by D E. WOOD (Grey), B Sc (London) The copyright of this thesis rests with the author No quotation from it should be published without his prior written consent and information derived from it should be acknowledged A candidate for the degree of Doctor of Philosophy 19 78 sr i i > j J To my MoLhcr and FaLhcr WLLII Lh.inks for .ill LhaL Lhey have done ACKNOWLEDGEMLNTS I would like LO express my thanks Lo Professor R D Chambers i under whose guidance this research was undertaken, for considerable encouragement, advice and discussion Thanks are due to Dr R S Matthews for his expert advice with n in r.
    [Show full text]
  • Risto Laitinen/August 4, 2016 International Union of Pure and Applied Chemistry Division VIII Chemical Nomenclature and Structur
    Approved Minutes, Busan 2015 Risto Laitinen/August 4, 2016 International Union of Pure and Applied Chemistry Division VIII Chemical Nomenclature and Structure Representation Approved Minutes of Division Committee Meeting in Busan, Korea, 8–9 August, 2015 1. Welcome, introductory remarks and housekeeping announcements Karl-Heinz Hellwich (KHH) welcomed everybody to the meeting, extending a special welcome to those who were attending the Division Committee meeting for the first time. He described house rules and arrangements during the meeting. KHH also regretfully reported that it has come to his attention that since the Bangor meeting in August 2014, Prof. Derek Horton (Member, Division VIII task groups on Carbohydrate and Flavonoids nomenclature; Associate Member, IUBMB-IUPAC Joint Commission on Biochemical Nomenclature) and Dr. Libuse Goebels, Member of the former Commission on Nomenclature of Organic Chemistry) have passed away. The meeting attendees paid a tribute to their memory by a moment of silence. 2. Attendance and apologies Present: Karl-Heinz Hellwich (president, KHH) , Risto Laitinen (acting secretary, RSL), Richard Hartshorn (past-president, RMH), Michael Beckett (MAB), Alan Hutton (ATH), Gerry P. Moss (GPM), Michelle Rogers (MMR), Jiří Vohlídal (JV), Andrey Yerin (AY) Observers: Leah McEwen (part time, chair of proposed project, LME), Elisabeth Mansfield (task group chair, EM), Johan Scheers (young observer, day 1; JS), Prof. Kazuyuki Tatsumi (past- president of the union, part of day 2) Apologies: Ture Damhus (secretary, TD), Vefa Ahsen, Kirill Degtyarenko, Gernot Eller, Mohammed Abul Hashem, Phil Hodge (PH), Todd Lowary, József Nagy, Ebbe Nordlander (EN), Amélia Pilar Rauter (APR), Hinnerk Rey (HR), John Todd, Lidija Varga-Defterdarović.
    [Show full text]
  • I. MATRIX ISOLATION of 1,1-DIAZENES II. DISTANCE, TEMPERATURE, and DYNAMIC SOLVENT EFFECTS on ELECTRON TRANSFER REACTIONS Thesis
    I. MATRIX ISOLATION OF 1,1-DIAZENES II. DISTANCE, TEMPERATURE, AND DYNAMIC SOLVENT EFFECTS ON ELECTRON TRANSFER REACTIONS Thesis by James Edward Hanson In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 1990 (Submitted September 8, 1989) 11 © 1990 James Edward Hanson All rights Reserved ill Acknowledgements I would like to thank my advisor, Peter Dervan , for his enthusiasm and support during my studies at Caltech. I would also like to thank Professor John Hopfield for his availability when I needed assistance with the theoretical complexities of the electron transfer work. I am deeply indebted to Lutfur "Zeta" Khundkar and Joe Perry for their expert assistance and collaboration in making measurements and understanding the implications of the results. Al Sylwester was extremely helpful in my first year as I began to work on 1,1-diazenes, and Alvin Joran and Burt Leland made my transition to the electron transfer project relatively simple. I should also thank those in the Dervan group who helped me with synthetic problems, especially John Griffin and Warren Wade. I appreciated discussions with some of the electron transfer experts at Caltech: Professor Rudy Marcus, Dave Beratan, Jose Onuchic, Dave Malerba, and Tad Fox. There were many times when the men in the chemistry shops provided invaluable assistance--you guys are the best! There are many who made my stay at Caltech enjoyable--I'll remember skiing with John and Linda Griffin and Heinz Moser, basketball (and marathons!) with Dave Kaisaki, tennis with Erich Uffelmann, and late night conversations with Kevin Luebke.
    [Show full text]
  • Studies on New Vasodilators, Ws-1228 a and B Ii. Structure and Synthesis
    VOL. XXXV NO. 2 THE JOURNAL OF ANTIBIOTICS 157 STUDIES ON NEW VASODILATORS, WS-1228 A AND B II. STRUCTURE AND SYNTHESIS HIROKAZU TANAKA, KEIZO YOSHIDA, YOSHIKUNI ITOH and HIROSHI IMANAKA Fermentation Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., Osaka, Japan (Received for publication October 26, 1981) The structure of new hypotensive vasodilators, WS-1228 A and B, produced by Strepto- myces aureofaciens, were determined as I and 2, respectively, on the basis of their spectral and chemical evidences. WS-1228 A (1), having N-hydroxytriazene moiety, was synthesized from (E,E,E)-2,4,7- undecatrienal (4) by condensation with hydrazine hydrate followed by nitrosation. In the course of screening for new biologically active compounds, we found that Streptomyces aureofaciens produces hypotensive vasodilators designated as WS-1228 A (1) and B (2). Taxonomy, isolation and characterization of these compounds have been reported in the preceding papery. This report describes the structure elucidations of WS-1228 A (1) and B (2) and the synthesis of 1. WS-1228 A (1) WS-1228 B (2) WS-1228 A (1) was isolated as yellow needles [mp 100 - 102°C (dec.)] which showed a positive color reaction to ferric chloride reagent. Elemental analysis and mass spectrum established the molecular formula of 1 as C11H17N3O. Absorption bands at 1612 and 1580 cm-1 in its IR spectrum (Fig. 1) and at 300 nm in its UV spectrum suggested the presence of the triene oxime moiety. The PMR spectrum (Fig. Fig. 1. IR spectrum of WS-1228 A (1) (Nujol). 158 THE JOURNAL OF ANTIBIOTICS FEB.
    [Show full text]
  • Ger'g .Tyson Jr
    July 14, 1964 ' G. N. TYSON, JR 3,140,582 ROCKET PROPULSION METHOD USING BORON AND NITROGEN COMPOUNDS Filed April 14, 1959 Ger'g .Tyson Jr. INVENTOR. I", u .12) ATTORNEYS 3,l4,582 Patented July 14,, 1964 2 The nitrogen containing compound and the boron con 3,140,582 taining compound are reacted in such proportions that all ROCKET PROPULSION METHOD USING BORON of the nitrogen and all of the boron react to produce AND NOGEN COMPOUNDS boron nitride, the carbon is released as elemental carbon George N. Tyson, Jr., Claremont, Calif., assignor to Olin Mathieson Chemical Corporation, a corporation of and large volumes of hydrogen gas are produced. Virginia Nitrogen containing compounds which can be employed Filed Apr. 14, 1959, Ser. No. 806,396 as reactants include the saturated hydronitrogens such 20 Claims. (Cl. 60-354) as ammonia, hydrazine, triazane, tetrazane; the unsaturated hydronitrogens such as diimide, triazene, tetrazene, iso This invention relates to a method for producing large 10 tetrazene, ammonium azide, hydrazine azide, and hydra volumes of hot gases in a short period of time, which zoic acid; alkyl hydrazines such as methyl hydrazine, un large volumes of hot gases are useful for many purposes symmetrical dimethyl hydrazine, ethyl hydrazine, unsym including imparting thrust to jet propelled devices such metrical diethyl hydrazine; alkylamines including mixed al as rockets. kylamines such as methylamine, dimethylamine, trimeth Jet propelled devices are essentially of two types: those 15 ylamine, ethylamine, diethylamine, triethylarnine, methyl which depend upon an external source for a portion of ethyl amine, n-propylamine, isopropylamine, di-n-propyl the propellant, and those in which the propellant is en amine, tri-n-propylamine, methyl propyl amine, ethyl prop tirely contained within the device.
    [Show full text]
  • Ammonia a Very Important Molecule for Biological Organisms to Make Proteins Or Nucleic Acids
    Ammonia A very important molecule for biological organisms to make proteins or nucleic acids by QH, and Niloy Kumar Das Shahjalal Science & Technology University, Bangladesh Molecule of the Month - June 2013 Introduction Ammonia or azane is a compound of nitrogen and hydrogen with the formula NH3. It is a colorless gas with a characteristic pungent smell, which is very common in toilets sometime. It is used in industry and commerce, and also exists naturally in humans and in the environment. Ammonia is essential for many biological processes and serves as a precursor for amino acid and nucleotide synthesis. In the environment, ammonia is part of the nitrogen cycle and is produced in soil from bacterial processes. Ammonia is also produced naturally from decomposition of organic matter, including plants and animals. Sal Ammoniacus Sal ammoniac is a mineral composed of ammonium chloride. The Romans called the ammonium chloride deposits they collected from near the Temple of Jupiter Amun in ancient Libya 'sal ammoniacus' (salt of Amun) because of proximity to the nearby temple. It is the earliest known mineral source of ammonia. Fig: Sal ammoniac is a mineral Guano & saltpeter Later alternative sources of ammonia mineral were discovered. Guano and saltpeter played valuable roleas strategic commodity. Guano consists of ammonium oxalate and urate, phosphates, as well as some earth salts and impurities. Guano also has a high concentration of nitrates. Saltpeter is the mineral form of potassium nitrate (KNO3). Potassium and other nitrates are of great importance for use in fertilizers, and, historically, gunpowder. Fig: Guano is simply deposits of bird droppings Independence from mineral dependency Even though our atmosphere consists 78% nitrogen, atmospheric nitrogen is nutritionally unavailable to plants or animals because nitrogen molecules are held together by strong triple bonds.
    [Show full text]
  • Hydroxylamine-O -Sulfonic Acid — a Versatile Synthetic Reagent
    Hydroxylamine-O -sulfonic acid — a versatile synthetic reagent Raymond G. Wallacef School of Chemistry Brunei University Uxbridge, Middlesex UBS 3PH Great Britain imidazoli nones and related derivatives are time to these various modes of reaction. discussed in the review. Many of these The uses of HOSA as a reagent are organiz­ preparations can be carried out in high ed below according to the different syn­ yield, thetic transformations that it can bring about. Hydroxylamine-Osulfonic acid, NHj-OSOjH (abbreviated to HOSA in Probably by far the most well known this article) has become in recent years and explored reactions of HOSA are commercially available. Although much animation reactions, illustrating elec­ fruitful chemistry has been carried out us­ trophilic attack by HOSA, with amination ing HOSA, to this author's knowledge, on nitrogen being the most important, there has been no systematic review in although a significant number of English* of its use as a synthetic reagent. It animations on both carbon and sulfur have is a chemically interesting compound been reported, Amination on phosphorus because of the ability of the nitrogen center also occurs. to act in the role of both nucleophile and AMINATION electrophile, dependent on circumstances, Synopsis (a) At a nitrogen atom and thus it has proved to be a reagent of Hydroxylamine-0-sulfonic acid (0 Preparation of mono- and di- great synthetic versatility. (HOSA) has only recently become widely substituted hydrazines and trisubstituied commercially available despite the fact that H,N-Nu hydrazinium salts it has proved to be a valuable synthetic reagent in preparative organic chemistry.
    [Show full text]
  • Condensed-Phase Photochemistry in the Absence of Radiation Chemistry Ella Mullikin
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Wellesley College Wellesley College Wellesley College Digital Scholarship and Archive Faculty Research and Scholarship 6-27-2018 Condensed-Phase Photochemistry in the Absence of Radiation Chemistry Ella Mullikin Pierce van Mulbregt Jeniffer Perea Muhammad Kasule Jean Huang See next page for additional authors Follow this and additional works at: https://repository.wellesley.edu/scholarship Version: Post-print Recommended Citation E. Mullikin, P. van Mulbregt, J. Perea, M. Kasule, J. Huang, C. Buffo, J. Campbell, L. Gates, H. M. Cumberbatch, Z. Peeler, H. Schneider, J. Lukens, S. T. Bao, R. Tano-Menka, S. Baniya, K. Cui, M. Thompson, A. Hay, L. Widdup, A. Caldwell-Overdier, J. Huang, M. C. Boyer, M. Rajappan, G. Echebiri and C. R. Arumainayagam, ACS Earth and Space Chemistry, 2018, DOI: 10.1021/ acsearthspacechem.8b00027. This Article is brought to you for free and open access by Wellesley College Digital Scholarship and Archive. It has been accepted for inclusion in Faculty Research and Scholarship by an authorized administrator of Wellesley College Digital Scholarship and Archive. For more information, please contact [email protected]. Authors Ella Mullikin, Pierce van Mulbregt, Jeniffer Perea, Muhammad Kasule, Jean Huang, Christina Buffo, Jyoti Campbell, Leslie Gates, Helen M. Cumberbatch, Zoe Peeler, Hope Schneider, Julia Lukens, Si Tong Bao, Rhoda Tano-Menka, Subha Baniya, Kendra Cui, Mayla Thompson, Aury Hay, Lily Widdup, Anna Caldwell- Overier, Justine Huang, Michael C. Boyer, Mahesh Rajappan, Geraldine Echebiri, and Christopher R. Arumainayagam This article is available at Wellesley College Digital Scholarship and Archive: https://repository.wellesley.edu/scholarship/183 Condensed-Phase Photochemistry in the Absence of Radiation Chemistry Ella Mullikin,1 Pierce van Mulbregt,2 Jeniffer Perea,1 Muhammad Kasule,3 Jean Huang,1 Christina Buffo,1 Jyoti Campbell,1 Leslie Gates,1 Helen M.
    [Show full text]
  • Adapting Neural Machine Translation to Predict IUPAC Names from a Chemical Identifier
    Translating the molecules: adapting neural machine translation to predict IUPAC names from a chemical identifier Jennifer Handsel*,a, Brian Matthews‡,a, Nicola J. Knight‡,b, Simon J. Coles‡,b aScientific Computing Department, Science and Technology Facilities Council, Didcot, OX11 0FA, UK. bSchool of Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK. KEYWORDS seq2seq, InChI, IUPAC, transformer, attention, GPU ABSTRACT We present a sequence-to-sequence machine learning model for predicting the IUPAC name of a chemical from its standard International Chemical Identifier (InChI). The model uses two stacks of transformers in an encoder-decoder architecture, a setup similar to the neural networks used in state-of-the-art machine translation. Unlike neural machine translation, which usually tokenizes input and output into words or sub-words, our model processes the InChI and predicts the 1 IUPAC name character by character. The model was trained on a dataset of 10 million InChI/IUPAC name pairs freely downloaded from the National Library of Medicine’s online PubChem service. Training took five days on a Tesla K80 GPU, and the model achieved test-set accuracies of 95% (character-level) and 91% (whole name). The model performed particularly well on organics, with the exception of macrocycles. The predictions were less accurate for inorganic compounds, with a character-level accuracy of 71%. This can be explained by inherent limitations in InChI for representing inorganics, as well as low coverage (1.4 %) of the training data. INTRODUCTION The International Union of Pure and Applied Chemistry (IUPAC) define nomenclature for both organic chemistry2 and inorganic chemistry.3 Their rules are comprehensive, but are difficult to apply to complicated molecules.
    [Show full text]
  • Reversing the Native Aerobic Oxidation Reactivity of Graphitic Carbon: Heterogeneous Metal-Free Alkene Hydrogenation
    Reversing the Native Aerobic Oxidation Reactivity of Graphitic Carbon: Heterogeneous Metal-Free Alkene Hydrogenation The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Murray, Alexander T. and Yogesh Surendranath. “Reversing the Native Aerobic Oxidation Reactivity of Graphitic Carbon: Heterogeneous Metal-Free Alkene Hydrogenation.” ACS Catalysis 7, 5 (April 2017): 3307–3312 © 2017 American Chemical Society As Published http://dx.doi.org/10.1021/acscatal.7b00395 Publisher American Chemical Society (ACS) Version Author's final manuscript Citable link http://hdl.handle.net/1721.1/115122 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. Reversing The Native Aerobic Oxidation Reactivity Of Graphitic Car- bon: Heterogeneous Metal-Free Alkene Hydrogenation Alexander T. Murray and Yogesh Surendranath* Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States. KEYWORDS Hydrogenation, Carbon Black, Carbocatalysis, Diimide, Alkene ABSTRACT: Commercially available carbon blacks serve as effective metal-free catalysts for the selective hydrogenation of car- bon-carbon multiple bonds under aerobic conditions using hydrazine as the terminal reductant. The reaction, which proceeds through a putative diimide intermediate, displays high tolerance to a variety of functional groups, including those sensitive to nu- cleophilic displacement by hydrazine, aerobic oxidation, or hydrazine-mediated reduction. Hydrazine chemisorbs strongly to the carbon surface, attenuating its native oxidative reactivity and allowing for selective hydrogenation. The catalytic sequence estab- lished here effectively umpolungs the reactivity of carbon, thereby enabling the use of this low cost material in selective reduction catalysis.
    [Show full text]
  • Bis(N-Heterocyclic Carbene)Carbazolide Pincer Complexes of S- and P-Block Metals and Related Studies
    AUSTRALIA Bis(N-Heterocyclic Carbene)Carbazolide Pincer Complexes of s- and p-Block Metals and Related Studies A thesis in partial fulfilment of the requirements for the degree of Doctor of Philosophy (Chemistry) by Kai N. Buys Supervisor: Assoc. Prof. Marcus L. Cole School of Chemistry The University of New South Wales Sydney, Australia April 2017 THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: BUYS First name: KAI Other name/s: NICHOLAS Abbreviation for degree as given in the University calendar: PhD School: CHEMISTRY Faculty: SCIENCE Title: Bis(N Heterocyclic Carbene)Carbazolide Pincer Complexes of s- and p-Block Metals and Related Studies Abstract 350 words maximum: This work presents synthetic investigations into main group organometallic chemistry, placing particular emphasis on the study of bis-N-heterocyclic carbene (NHC) carbazolide coordination environments. Complexes of high and low oxidation state metals from the s- and p-blocks were targeted and these comprise the content of the experimental chapters two through five. Chapter one serves as a general introduction to rationalise the intent of this work. Herein focus is drawn to the nascent field of organometallic main group chemistry in the form of a discussion of its history using pertinent recent examples from the literature. Chapter two details the synthesis of an emerging class of versatile bis(NHC)carbazolide pincer ligands; bimcaR, and their complexation to s-block metals. The development of a new zwitterionic bis(imidazolium)carbazolide proligand is discussed, as well as the structural metrics of new lithium and magnesium bimcaR derivatives. Specifically, a new iodomagnesium complex is probed for its synthetic utility as a ligand-transfer agent and catalytic precursor in conjunction with attempts to access a reduced Mg(I) derivative.
    [Show full text]
  • Diimide Reduction of Liquid Natural Rubber in Hydrazine Hydrate/Hydrogen Peroxide System: a Side Reaction Study
    Malaysian Journal of Analytical Sciences, Vol 22 No 6 (2018): 1023 - 1030 DOI: https://doi.org/10.17576/mjas-2018-2206-11 MALAYSIAN JOURNAL OF ANALYTICAL SCIENCES ISSN 1394 - 2506 Published by The Malaysian Analytical Sciences Society DIIMIDE REDUCTION OF LIQUID NATURAL RUBBER IN HYDRAZINE HYDRATE/HYDROGEN PEROXIDE SYSTEM: A SIDE REACTION STUDY (Penurunan Diimida Getah Asli Cecair dalam Sistem Hidrazin Hidrat/Hidrogen Peroksida: Kajian Tindak Balas Sampingan) Muhammad Jefri Mohd Yusof1, Nur Aidasyakirah Mohd Tahir1, Fazira Firdaus1, Siti Fairus M. Yusoff1,2* 1School of Chemical Sciences and Food Technology, Faculty of Science and Technology 2Polymer Research Centre, Faculty of Science and Technology Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia *Corresponding author: [email protected] Received: 27 July 2017; Accepted: 28 April 2018 Abstract Hydrogenation of liquid natural rubber (LNR) has been successfully accomplished via diimide reduction using hydrazine hydrate/hydrogen peroxide (HH/H2O2) system. Each parameter in the system was optimized to obtain maximum hydrogenation degree such as the mass of boric acid, mole ratio of HH: H2O2, reaction time and reaction temperature. As a result, the highest degree of hydrogenation was achieved at 91.2% using a molar ratio HH: H2O2 of 2:3, in the presence of boric acid as a promoter at 60 °C for 8 hours. In this research, we report on possible side reactions that led to lowering the hydrogenated rubber product. Reactivity of diimide species as well as decomposition of hydrogen peroxide were postulated based on literature reviews to be one of the factors hindering hydrogenation of LNR. The presence of side reactions such as degradation, cyclization, and crosslinking had been confirmed by gel permeation chromatography (GPC), 1H nuclear magnetic resonance (1H NMR), and swelling test, respectively.
    [Show full text]