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A chromium(III)-superoxo complex in oxygen atom transfer reactions as a chemical model of cysteine dioxygenase

Title
A chromium(III)-superoxo complex in oxygen atom transfer reactions as a chemical model of cysteine dioxygenase
Authors
Cho J.Woo J.Nam W.
Ewha Authors
남원우조재흥
SCOPUS Author ID
남원우scopus
Issue Date
2012
Journal Title
Journal of the American Chemical Society
ISSN
0002-7863JCR Link
Citation
vol. 134, no. 27, pp. 11112 - 11115
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Metal-superoxo species are believed to play key roles in oxygenation reactions by metalloenzymes. One example is cysteine dioxygenase (CDO) that catalyzes the oxidation of cysteine with O 2, and an iron(III)-superoxo species is proposed as an intermediate that effects the sulfoxidation reaction. We now report the first biomimetic example showing that a chromium(III)-superoxo complex bearing a macrocyclic TMC ligand, [Cr III(O 2)(TMC)(Cl)] +, is an active oxidant in oxygen atom transfer (OAT) reactions, such as the oxidation of phosphine and sulfides. The electrophilic character of the Cr(III)-superoxo complex is demonstrated unambiguously in the sulfoxidation of para-substituted thioanisoles. A Cr(IV)-oxo complex, [Cr IV(O)(TMC)(Cl)] +, formed in the OAT reactions by the chromium(III)-superoxo complex, is characterized by X-ray crystallography and various spectroscopic methods. The present results support the proposed oxidant and mechanism in CDO, such as an iron(III)-superoxo species is an active oxidant that attacks the sulfur atom of the cysteine ligand by the terminal oxygen atom of the superoxo group, followed by the formation of a sulfoxide and an iron(IV)-oxo species via an O-O bond cleavage. © 2012 American Chemical Society.
DOI
10.1021/ja304357z
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자연과학대학 > 화학·나노과학전공 > Journal papers
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