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Cu(II)‐catalyzed oxidation of thiols by superoxide ligated to Co III 2
Author(s) -
Mishra Ritu,
Banerjee Rupendranath,
Mukhopadhyay Subrata
Publication year - 2012
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.2991
Subject(s) - chemistry , thiol , catalysis , catalytic cycle , copper , reaction rate constant , kinetics , superoxide , polymer chemistry , photochemistry , medicinal chemistry , organic chemistry , enzyme , physics , quantum mechanics
Copper(II) dramatically catalyzes the oxidation of thiols by a superoxide bridging two Co III ions. The catalyzed path overwhelmingly dominates over the uncatalysed path and is first order in the superoxo complex concentration. The first‐order rate constants show a first‐order dependence in [Cu 2+ ], a second‐order dependence in [thiol] and linearly varies with [H + ] −3 . On the basis of observed kinetics reported here, it is proposed that Cu(II) reacts with two thiol molecules to form a Cu II (thiol) 2 complex, an electron is transferred from one ligated thiol to the Cu II center to form Cu I (thiol) and a thiyl radical. The copper(I)‐thiol complex is oxidized by the conjugate base of the title complex to regenerate Cu II (thiol). A Cu II/I catalytic cycle is thus believed to be responsible for the observed catalysis. Copyright © 2012 John Wiley & Sons, Ltd.