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Mechanism of (Salen)manganese(III)‐Catalyzed Oxidation of Aryl Phenyl Sulfides with Sodium Hypochlorite
Author(s) -
Chellamani Arunachalam,
Harikengaram Sivalingam
Publication year - 2011
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201000234
Subject(s) - chemistry , manganese , aryl , substituent , metal salen complexes , sulfide , medicinal chemistry , catalysis , hypochlorite , electron transfer , reaction rate constant , hammett equation , oxidation state , substrate (aquarium) , inorganic chemistry , photochemistry , kinetics , organic chemistry , alkyl , physics , quantum mechanics , oceanography , geology
The oxidation of 4‐substituted phenyl phenyl sulfides was carried out with several oxo(salen)manganese(V) complexes in MeCN/H 2 O 9 : 1. The kinetic data show that the reaction is first‐order each in the oxidant and sulfide. Electron‐attracting substituents in the sulfides and electron‐releasing substituents in salen of the oxo(salen)manganese(V) complexes reduce the rate of oxidation. A Hammett analysis of the rate constants for the oxidation of 4‐substituted phenyl phenyl sulfides gives a negative ρ value ( ρ =−2.16) indicating an electron‐deficient transition state. The log k 2 values observed in the oxidation of each 4‐substituted phenyl phenyl sulfide by substituted oxo(salen)manganese(V) complexes also correlate with Hammett σ constants, giving a positive ρ value. The substituent‐, acid‐, and solvent‐effect studies indicate direct O‐atom transfer from the oxidant to the substrate in the rate‐determining step.