1
|
Barbosa WG, Santos-Jr CV, Andrade RB, Lucena JR, Moura RT. Bond analysis in meta- and para-substituted thiophenols: overlap descriptors, local mode analysis, and QTAIM. J Mol Model 2024; 30:139. [PMID: 38639900 DOI: 10.1007/s00894-024-05932-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/07/2024] [Indexed: 04/20/2024]
Abstract
CONTEXT This study delves into the chemical nuances of thiophenols and their derivatives through a comprehensive computational analysis, moving beyond traditional energetic perspectives such as bond dissociation enthalpy and S-H dissociation dynamics. By employing the overlap model along with its topological descriptors (OP/TOP), quantum theory of atoms in molecules (QTAIM), and local vibrational mode (LVM) theories, the research provides a deeper understanding of the S-H and C-S bonding scenarios in substituted thiophenols. The investigation follows the electron-donating capacity of S-H substituent variation with the nature and positioning of other ring substituents. Energy profile analyses indicate distinct stability differences in the cis and trans conformations of meta- and para-PhSH systems, influenced by the electron-donating strength of these substituents. The study also uncovers significant variations in S-H bond distances and descriptor values, particularly in para-substituted PhSH, reflecting the influence of electron-donating or withdrawing substituents. In contrast, alterations at the meta-position show minimal effects on C-S bond descriptors, while para-substitutions markedly influence C-S bond characteristics, demonstrating a clear correlation with the electron-donating or withdrawing capabilities of the substituents. This research sheds light on the intricate bond dynamics in aromatic systems with diverse substituents, highlighting the complex interaction between electronic effects and molecular conformation. METHODS The study employs the ω B97X-D/Def2TZVP level of theory for molecular geometries, ensuring accurate characterization of structures as true minima via analytical harmonic frequency determination. The electronic properties of S-H and C-S bonds in variously substituted thiophenols were analyzed using OP/TOP, QTAIM, and LVM methodologies. Computational processes, including conformational scans, geometry optimizations, and vibrational frequency calculations, were conducted using Gaussian 09, with ultra-fine integration grids and tight convergence criteria for the SCF procedure. Bond descriptors were computed utilizing ChemBOS, Multiwfn, and LModeA software, providing a robust and detailed examination of bond properties.
Collapse
Affiliation(s)
- Willis G Barbosa
- Department of Chemistry, State University of Paraiba, Campina Grande, 58429-500, PB, Brazil
| | - Carlos V Santos-Jr
- Department of Chemistry, Federal University of Paraiba, João Pessoa, 58051-970, PB, Brazil
| | - Railton B Andrade
- Department of Chemistry, State University of Paraiba, Campina Grande, 58429-500, PB, Brazil
| | - Juracy R Lucena
- Department of Chemistry, State University of Paraiba, Campina Grande, 58429-500, PB, Brazil
| | - Renaldo T Moura
- Department of Chemistry and Physics, Center of Agrarian Sciences, Federal University of Paraiba, Areia, 58397-000, PB, Brazil.
- Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, Dallas, TX, 75275, USA.
| |
Collapse
|
2
|
Kim J, Woo KC, Kim KK, Kang M, Kim SK. Tunneling dynamics dictated by the multidimensional conical intersection seam in the πσ*‐mediated photochemistry of heteroaromatic molecules. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Junggil Kim
- Department of Chemistry, KAIST Daejeon Republic of Korea
| | - Kyung Chul Woo
- Department of Chemistry, KAIST Daejeon Republic of Korea
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences Nanyang Technological University Singapore Singapore
| | - Kuk Ki Kim
- Department of Chemistry, KAIST Daejeon Republic of Korea
| | - Minseok Kang
- Department of Chemistry, KAIST Daejeon Republic of Korea
| | - Sang Kyu Kim
- Department of Chemistry, KAIST Daejeon Republic of Korea
| |
Collapse
|
3
|
|
4
|
Jiajun D, Maza JR, Xu Y, Xu T, Momen R, Kirk SR, Jenkins S. A stress tensor and QTAIM perspective on the substituent effects of biphenyl subjected to torsion. J Comput Chem 2016; 37:2508-17. [PMID: 27546220 DOI: 10.1002/jcc.24476] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 06/26/2016] [Accepted: 08/06/2016] [Indexed: 11/11/2022]
Abstract
The Quantum Theory of Atoms in Molecules (QTAIM) defines quantities in 3D space that can be easily obtained from routine quantum chemical calculations. The present investigation shows that local properties can be related quantitatively to measures traditionally connected to experimental data, such as Hammett constants. We consider the specific case of substituted biphenyl to quantify the effects of a torsion φ, 0.0° ≤ φ ≤ 180.0°, of the C-C bond linking the two phenyl rings for C12 H9 -x, where x = N(CH3 )2 , NH2 , CH3 , CHO, CN, NO2, on the entire molecule. QTAIM interpreted Hammett constants, aΔH(rb ) are introduced and constructed using the difference between the H(rb ) value of C12 H9 -x and the C12 H9 -H, biphenyl which is the reference molecule, with a constant of proportionality a. This investigation unexpectedly yields very good or good agreement for the x groups with the Hammett para-, meta-, and ortho-substituent constants and is checked against para-substituted benzene. We then proceed to present the interpreted substituent constants of seven new biphenyl substituent groups, where tabulated Hammett substituent constant values are not available; y = SiH3 , ZnCl, COOCH3 , SO2 NH2 , SO2 OH, COCl, CB3 . Consistency is found for the QTAIM interpreted biphenyl substituent constants of the seven new groups y independently using the stress tensor polarizability Pσ . In addition, a selection of future applications is discussed that highlight the usefulness of this approach. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- D Jiajun
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Resource Fine-Processing and Advanced Materials of Hunan Province of MOE, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha Hunan, 410081, China
| | - J R Maza
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Resource Fine-Processing and Advanced Materials of Hunan Province of MOE, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha Hunan, 410081, China
| | - Y Xu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Resource Fine-Processing and Advanced Materials of Hunan Province of MOE, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha Hunan, 410081, China
| | - T Xu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Resource Fine-Processing and Advanced Materials of Hunan Province of MOE, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha Hunan, 410081, China
| | - R Momen
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Resource Fine-Processing and Advanced Materials of Hunan Province of MOE, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha Hunan, 410081, China
| | - S R Kirk
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Resource Fine-Processing and Advanced Materials of Hunan Province of MOE, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha Hunan, 410081, China
| | - S Jenkins
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Resource Fine-Processing and Advanced Materials of Hunan Province of MOE, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha Hunan, 410081, China
| |
Collapse
|
5
|
Kim SY, Lee J, Kim SK, Choi YS. Nonplanar structure of C6H5SCF3 facilitates πσ∗-mediated photodissociation reaction on the S1 state. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.06.083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
6
|
Mardyukov A, Schreiner PR. Generation and characterization of the phenylthiyl radical and its oxidation to the phenylthiylperoxy and phenylsulfonyl radicals. Phys Chem Chem Phys 2016; 18:26161-26165. [DOI: 10.1039/c6cp04278c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The matrix-isolated phenylthiyl radical generated from diphenylsulfide reacts with O2to give the phenylthiylperoxy radical, which photoisomerizes to the more stable phenylsulfonyl radical.
Collapse
Affiliation(s)
- Artur Mardyukov
- Institute of Organic Chemistry
- Justus-Liebig University
- 35392 Giessen
- Germany
| | - Peter R. Schreiner
- Institute of Organic Chemistry
- Justus-Liebig University
- 35392 Giessen
- Germany
| |
Collapse
|
7
|
You HS, Han S, Yoon JH, Lim JS, Lee J, Kim SY, Ahn DS, Lim JS, Kim SK. Structure and dynamic role of conical intersections in the πσ*-mediated photodissociation reactions. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1072364] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
8
|
Kennedy N, Lu G, Liu P, Cohen T. Reductive Lithiation in the Absence of Aromatic Electron Carriers. A Steric Effect Manifested on the Surface of Lithium Metal Leads to a Difference in Relative Reactivity Depending on Whether the Aromatic Electron Carrier Is Present or Absent. J Org Chem 2015. [DOI: 10.1021/acs.joc.5b01136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicole Kennedy
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Gang Lu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Theodore Cohen
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| |
Collapse
|
9
|
Affiliation(s)
- Fabrice Dénès
- Laboratoire CEISAM UMR CNRS 6230 - UFR des Sciences et Techniques, Université de Nantes , 2 rue de la Houssinière, BP 92208 - 44322 Nantes Cedex 3, France
| | | | | | | |
Collapse
|
10
|
|
11
|
Zeng Q, Li Z, Dong L, Han D, Wang R, Li X, Bai G. Remote substituent effects on gas-phase homolytic Fe-O and Fe-S bond energies of p
-G-C6
H4
OFe(CO)2
(η
5
-C5
H5
) and p
-G-C6
H4
SFe(CO)2
(η
5
-C5
H5
) studied using Hartree-Fock and density functional theory methods. J PHYS ORG CHEM 2013. [DOI: 10.1002/poc.3152] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Qing Zeng
- School of Chinese Pharmacy; Beijing University of Chinese Medicine; Beijing 100102 China
- The State Key Laboratory of Elemento-organic Chemistry; Nankai University; Tianjin 300071 China
| | - Zucheng Li
- Department of Geological Sciences; University of Saskatchewan; 114 Science Place Saskatoon SK S7N 5E2 Canada
| | - Ling Dong
- School of Chinese Pharmacy; Beijing University of Chinese Medicine; Beijing 100102 China
| | - Daxiong Han
- The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemistry; Xiamen University; Xiamen 361005 China
| | - Rufeng Wang
- School of Chinese Pharmacy; Beijing University of Chinese Medicine; Beijing 100102 China
| | - Xiangri Li
- School of Chinese Pharmacy; Beijing University of Chinese Medicine; Beijing 100102 China
| | - Genben Bai
- School of Chinese Pharmacy; Beijing University of Chinese Medicine; Beijing 100102 China
| |
Collapse
|
12
|
Abu Safieh KA, Hasan AK, Ayoub MT, Mubarak MS. Preparation of some alkenoic acid derivatives as new plant growth regulators. RESEARCH ON CHEMICAL INTERMEDIATES 2013. [DOI: 10.1007/s11164-013-1315-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
13
|
Oliver TAA, King GA, Tew DP, Dixon RN, Ashfold MNR. Controlling Electronic Product Branching at Conical Intersections in the UV Photolysis of para-Substituted Thiophenols. J Phys Chem A 2012; 116:12444-59. [DOI: 10.1021/jp308804d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | - Graeme A. King
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - David P. Tew
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Richard N. Dixon
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | | |
Collapse
|
14
|
Wang L, Zhou WY, Chen SC, He MY, Chen Q. A Highly Efficient Palladium-Catalyzed One-Pot Synthesis of Unsymmetrical Aryl Alkyl Thioethers under Mild Conditions in Water. Adv Synth Catal 2012. [DOI: 10.1002/adsc.201100788] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
15
|
Rimarčík J, Lukeš V, Klein E, Rottmannová L. On the enthalpies of homolytic and heterolytic S–H bond cleavage in para and meta substituted thiophenols. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.04.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
16
|
Towards physical interpretation of Hammett constants: charge transferred between active regions of substituents and a functional group. Struct Chem 2010. [DOI: 10.1007/s11224-010-9676-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
17
|
Rogers DW, Zavitsas AA, Matsunaga N. Effects of Molecule Stabilization Energies on Radical Reactions: G3 and G3(MP2) Model Chemistries Applied to Benzylic Systems. J Phys Chem A 2009; 113:12049-55. [DOI: 10.1021/jp902354a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Donald W. Rogers
- Department of Chemistry and Biochemistry, Long Island University, University Plaza, Brooklyn, New York 11201
| | - Andreas A. Zavitsas
- Department of Chemistry and Biochemistry, Long Island University, University Plaza, Brooklyn, New York 11201
| | - Nikita Matsunaga
- Department of Chemistry and Biochemistry, Long Island University, University Plaza, Brooklyn, New York 11201
| |
Collapse
|
18
|
Bernardes CES, Minas da Piedade ME. Energetics of the O−H Bond and of Intramolecular Hydrogen Bonding in HOC6H4C(O)Y (Y = H, CH3, CH2CH═CH2, C≡CH, CH2F, NH2, NHCH3, NO2, OH, OCH3, OCN, CN, F, Cl, SH, and SCH3) Compounds. J Phys Chem A 2008; 112:10029-39. [DOI: 10.1021/jp804455u] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carlos E. S. Bernardes
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-016 Lisboa, Portugal
| | - Manuel E. Minas da Piedade
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-016 Lisboa, Portugal
| |
Collapse
|
19
|
Qi XJ, Li Z, Fu Y, Guo QX, Liu L. anti-Spin-Delocalization Effect in Co−C Bond Dissociation Enthalpies. Organometallics 2008. [DOI: 10.1021/om701135c] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Xiu-Juan Qi
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Zhe Li
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yao Fu
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Qing-Xiang Guo
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lei Liu
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| |
Collapse
|
20
|
Lim J, Lee Y, Kim S. Control of Intramolecular Orbital Alignment in the Photodissociation of Thiophenol: Conformational Manipulation by Chemical Substitution. Angew Chem Int Ed Engl 2008; 47:1853-6. [DOI: 10.1002/anie.200705358] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
21
|
Lim J, Lee Y, Kim S. Control of Intramolecular Orbital Alignment in the Photodissociation of Thiophenol: Conformational Manipulation by Chemical Substitution. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
22
|
Zavitsas AA, Rogers DW, Matsunaga N. Remote substituent effects on allylic and benzylic bond dissociation energies. Effects on stabilization of parent molecules and radicals. J Org Chem 2007; 72:7091-101. [PMID: 17715965 DOI: 10.1021/jo0707129] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The effect of remote substituents on bond dissociation energies (BDE) is examined by investigating allylic C-F and C-H BDE, as influenced by Y substituents in trans-YCH=CHCH2-F and trans-YCH=CHCH2-H. Theoretical calculations at the full G3 level model chemistry are reported. The interplay of stabilization energies of the parent molecules (MSE) and of the radicals formed by homolytic bond cleavage (RSE) and their effect on BDE are established. MSE values of allyl fluorides yield an excellent linear free energy relationship with the electron-donating or -withdrawing ability of Y and decrease by 4.2 kcal mol-1 from Y = (CH3)2N to O2N. RSE values do not follow a consistent pattern and are of the order of 1-2 kcal mol-1. A decrease of 4.1 kcal mol-1 is found in BDE[C-F] from Y = CH3O to NC. BDE[YCH=CHCH2-H] generally increases with decreasing electron-donating ability of Y for electron-donating groups and does not follow a consistent pattern with electron-withdrawing groups, the largest change being an increase of 3.6 kcal mol-1 from Y = (CH3)2N to CF3. The G3 results are an indicator of benzylic BDE in p-YC6H4CH2-F and p-YC6H4CH2-H, via the principle of vinylogy, demonstrated by correlating MSE of the allylic compounds with physical properties of their benzylic analogues.
Collapse
Affiliation(s)
- Andreas A Zavitsas
- Department of Chemistry and Biochemistry, Long Island University, University Plaza, Brooklyn, NY 11201, USA.
| | | | | |
Collapse
|
23
|
Mulder P, Mozenson O, Lin S, Ingold KU. The unexpected desulfurization of 4-aminothiophenols. J Org Chem 2007; 72:2379-86. [PMID: 17319726 DOI: 10.1021/jo0624243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thermolysis of 4-aminophenyl benzyl sulfide at 523 K in the hydrogen donor solvent (HDS), 9,10-dihydroanthracene (AnH2), gave 4-aminothiophenol and toluene as the predominant products of the homolytic S-C bond cleavage. Under these conditions, a portion of the 4-aminothiophenol was desulfurized to aniline with first-order kinetics and with a rate constant estimated by kinetic modeling to be 7.0x10(-6) s-1. Starting with 4-NH2C6H4SH at 523 K, it was found that sulfur loss was more efficient in the non-HDSs, anthracene and hexadecane, than in AnH2. Under similar (competitive) reaction conditions, YC6H4SHs with Y=H, 4-CN, and 3-CF3 were completely inert; with Y=4-CH3O, there was some very minor desulfurization, whereas with Y=4-N(CH3)2 and 4-N(CH3)(H), the sulfur extrusions were as fast as that for Y=4-NH2. We tentatively suggest that this apparently novel reaction is a chain process initiated by the bimolecular formation of diatomic sulfur, S2, followed by a reversible addition of ground state, triplet 3S2 to the thiol sulfur atom, 4-NH2C6H4S upward arrow(SS upward arrow)H, and insertion into the S-H bond, 4-NH2C6H4SSSH. In a cascade of reactions, aniline and S8 are formed with the chains being terminated by reaction of 4-NH2C6H4S upward arrow(SS upward arrow)H with 4-NH2C6H4SH. Such a reaction mechanism is consistent with the first-order kinetics. That this reaction is primarily observed with 4-YC6H4SH having Y=N(CH3)2, N(CH3)(H), and NH2 is attributed to the fact that these compounds can exist as zwitterions.
Collapse
Affiliation(s)
- Peter Mulder
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
| | | | | | | |
Collapse
|