Mechanism for the reactions of sulfides with hypochlorous acid and N-chlorosulfon-amides: Formation of solvated chlorosulfonium cation and λ4-sulfane intermediates

Ferenc Ruff, D. Szabó, J. Rábai, István Jalsovszky, O. Farkas

Research output: Contribution to journalArticle

Abstract

DFT computations have been performed to study the mechanism of the reactions of sulfides with hypochlorous acid and N-chlorosulfonamides. Sulfides can attack HOCl both at chlorine and oxygen atoms. The attack at chlorine results in the formation of chlorosulfonium cation (R2SCl+) and OH intermediates, which transform to sulfoxide product. The high free energy of activation (ΔG), which is needed for the formation of ionic intermediates, is decreased considerably by solvation in protic solvents. Since the attack of sulfides at the oxygen atom of HOCl has low ΔG value, the chlorination of sulfides can compete with the attack at the oxygen atom only in protic solvents. Kinetic studies showed that the reactivity of species, formed from N-chlorosulfonamides in protic solvents, increases in the course: RSO2NCl << RSO2NHCl < < RSO2NCl2. The chlorination of sulfides with RSO2NHCl or RSO2NCl2 results in the formation of R2SCl+ and RSO2NH or RSO2NCl intermediates, respectively, and the computed and experimentally derived ΔG data agree in these cases. Sulfilimine (R2S═NSO2R) and sulfoxide products are formed in the reaction of R2SCl+ with RSO2NH and water, respectively. Acyloxy-chloro-λ4-sulfane intermediates are produced in the reactions of N-chlorosulfonamides and sulfides, bearing 2-carboxy-phenyl group, without the intermediacy of chlorosulfonium cations. Explicit water molecules must also be included in computations for reactions proceeding with formation or destruction of ions, to get ΔG values, comparable with experimental data. Supporting information may be found in the online version of this paper.

Original languageEnglish
Article numbere4005
JournalJournal of Physical Organic Chemistry
DOIs
Publication statusPublished - Jan 1 2019

Fingerprint

Hypochlorous Acid
Sulfides
Amides
amides
Cations
sulfides
sulfoxide
cations
acids
attack
oxygen atoms
chlorination
Chlorination
Chlorine
Oxygen
Atoms
chlorine
Bearings (structural)
Water
Solvation

Keywords

  • chlorination
  • DFT calculations
  • hypochlorous acid
  • N-chlorosulfonamides
  • sulfides

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

Cite this

@article{6c6c5f1ab811470e888f8566577a2b54,
title = "Mechanism for the reactions of sulfides with hypochlorous acid and N-chlorosulfon-amides: Formation of solvated chlorosulfonium cation and λ4-sulfane intermediates",
abstract = "DFT computations have been performed to study the mechanism of the reactions of sulfides with hypochlorous acid and N-chlorosulfonamides. Sulfides can attack HOCl both at chlorine and oxygen atoms. The attack at chlorine results in the formation of chlorosulfonium cation (R2SCl+) and OH− intermediates, which transform to sulfoxide product. The high free energy of activation (ΔG‡), which is needed for the formation of ionic intermediates, is decreased considerably by solvation in protic solvents. Since the attack of sulfides at the oxygen atom of HOCl has low ΔG‡ value, the chlorination of sulfides can compete with the attack at the oxygen atom only in protic solvents. Kinetic studies showed that the reactivity of species, formed from N-chlorosulfonamides in protic solvents, increases in the course: RSO2NCl− << RSO2NHCl < < RSO2NCl2. The chlorination of sulfides with RSO2NHCl or RSO2NCl2 results in the formation of R2SCl+ and RSO2NH− or RSO2NCl− intermediates, respectively, and the computed and experimentally derived ΔG‡ data agree in these cases. Sulfilimine (R2S═NSO2R) and sulfoxide products are formed in the reaction of R2SCl+ with RSO2NH− and water, respectively. Acyloxy-chloro-λ4-sulfane intermediates are produced in the reactions of N-chlorosulfonamides and sulfides, bearing 2-carboxy-phenyl group, without the intermediacy of chlorosulfonium cations. Explicit water molecules must also be included in computations for reactions proceeding with formation or destruction of ions, to get ΔG‡ values, comparable with experimental data. Supporting information may be found in the online version of this paper.",
keywords = "chlorination, DFT calculations, hypochlorous acid, N-chlorosulfonamides, sulfides",
author = "Ferenc Ruff and D. Szab{\'o} and J. R{\'a}bai and Istv{\'a}n Jalsovszky and O. Farkas",
year = "2019",
month = "1",
day = "1",
doi = "10.1002/poc.4005",
language = "English",
journal = "Journal of Physical Organic Chemistry",
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TY - JOUR

T1 - Mechanism for the reactions of sulfides with hypochlorous acid and N-chlorosulfon-amides

T2 - Formation of solvated chlorosulfonium cation and λ4-sulfane intermediates

AU - Ruff, Ferenc

AU - Szabó, D.

AU - Rábai, J.

AU - Jalsovszky, István

AU - Farkas, O.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - DFT computations have been performed to study the mechanism of the reactions of sulfides with hypochlorous acid and N-chlorosulfonamides. Sulfides can attack HOCl both at chlorine and oxygen atoms. The attack at chlorine results in the formation of chlorosulfonium cation (R2SCl+) and OH− intermediates, which transform to sulfoxide product. The high free energy of activation (ΔG‡), which is needed for the formation of ionic intermediates, is decreased considerably by solvation in protic solvents. Since the attack of sulfides at the oxygen atom of HOCl has low ΔG‡ value, the chlorination of sulfides can compete with the attack at the oxygen atom only in protic solvents. Kinetic studies showed that the reactivity of species, formed from N-chlorosulfonamides in protic solvents, increases in the course: RSO2NCl− << RSO2NHCl < < RSO2NCl2. The chlorination of sulfides with RSO2NHCl or RSO2NCl2 results in the formation of R2SCl+ and RSO2NH− or RSO2NCl− intermediates, respectively, and the computed and experimentally derived ΔG‡ data agree in these cases. Sulfilimine (R2S═NSO2R) and sulfoxide products are formed in the reaction of R2SCl+ with RSO2NH− and water, respectively. Acyloxy-chloro-λ4-sulfane intermediates are produced in the reactions of N-chlorosulfonamides and sulfides, bearing 2-carboxy-phenyl group, without the intermediacy of chlorosulfonium cations. Explicit water molecules must also be included in computations for reactions proceeding with formation or destruction of ions, to get ΔG‡ values, comparable with experimental data. Supporting information may be found in the online version of this paper.

AB - DFT computations have been performed to study the mechanism of the reactions of sulfides with hypochlorous acid and N-chlorosulfonamides. Sulfides can attack HOCl both at chlorine and oxygen atoms. The attack at chlorine results in the formation of chlorosulfonium cation (R2SCl+) and OH− intermediates, which transform to sulfoxide product. The high free energy of activation (ΔG‡), which is needed for the formation of ionic intermediates, is decreased considerably by solvation in protic solvents. Since the attack of sulfides at the oxygen atom of HOCl has low ΔG‡ value, the chlorination of sulfides can compete with the attack at the oxygen atom only in protic solvents. Kinetic studies showed that the reactivity of species, formed from N-chlorosulfonamides in protic solvents, increases in the course: RSO2NCl− << RSO2NHCl < < RSO2NCl2. The chlorination of sulfides with RSO2NHCl or RSO2NCl2 results in the formation of R2SCl+ and RSO2NH− or RSO2NCl− intermediates, respectively, and the computed and experimentally derived ΔG‡ data agree in these cases. Sulfilimine (R2S═NSO2R) and sulfoxide products are formed in the reaction of R2SCl+ with RSO2NH− and water, respectively. Acyloxy-chloro-λ4-sulfane intermediates are produced in the reactions of N-chlorosulfonamides and sulfides, bearing 2-carboxy-phenyl group, without the intermediacy of chlorosulfonium cations. Explicit water molecules must also be included in computations for reactions proceeding with formation or destruction of ions, to get ΔG‡ values, comparable with experimental data. Supporting information may be found in the online version of this paper.

KW - chlorination

KW - DFT calculations

KW - hypochlorous acid

KW - N-chlorosulfonamides

KW - sulfides

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