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Synthesis, structural, and spectroscopic characterization and reactivities of mononuclear cobalt(III)-peroxo complexes

Title
Synthesis, structural, and spectroscopic characterization and reactivities of mononuclear cobalt(III)-peroxo complexes
Authors
Cho J.Sarangi R.Kang H.Y.Lee J.Y.Kubo M.Ogura T.Solomon E.I.Nam W.
Ewha Authors
남원우조재흥
SCOPUS Author ID
남원우scopus
Issue Date
2010
Journal Title
Journal of the American Chemical Society
ISSN
0002-7863JCR Link
Citation
vol. 132, no. 47, pp. 16977 - 16986
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Metal-dioxygen adducts are key intermediates detected in the catalytic cycles of dioxygen activation by metalloenzymes and biomimetic compounds. In this study, mononuclear cobalt(III)-peroxo complexes bearing tetraazamacrocyclic ligands, [Co(12-TMC)(O 2)] + and [Co(13-TMC)(O 2)] +, were synthesized by reacting [Co(12-TMC)(CH 3CN)] 2+ and [Co(13-TMC)(CH 3CN)] 2+, respectively, with H 2O 2 in the presence of triethylamine. The mononuclear cobalt(III)-peroxo intermediates were isolated and characterized by various spectroscopic techniques and X-ray crystallography, and the structural and spectroscopic characterization demonstrated unambiguously that the peroxo ligand is bound in a side-on η 2 fashion. The O-O bond stretching frequency of [Co(12-TMC)(O 2)] + and [Co(13-TMC)(O 2)] + was determined to be 902 cm -1 by resonance Raman spectroscopy. The structural properties of the CoO 2 core in both complexes are nearly identical; the O-O bond distances of [Co(12-TMC)(O 2)] + and [Co(13-TMC)(O 2)] + were 1.4389(17) Å and 1.438(6) Å, respectively. The cobalt(III)-peroxo complexes showed reactivities in the oxidation of aldehydes and O 2-transfer reactions. In the aldehyde oxidation reactions, the nucleophilic reactivity of the cobalt-peroxo complexes was significantly dependent on the ring size of the macrocyclic ligands, with the reactivity of [Co(13-TMC)(O 2)] + > [Co(12-TMC)(O 2)] +. In the O 2-transfer reactions, the cobalt(III)-peroxo complexes transferred the bound peroxo group to a manganese(II) complex, affording the corresponding cobalt(II) and manganese(III)-peroxo complexes. The reactivity of the cobalt-peroxo complexes in O 2-transfer was also significantly dependent on the ring size of tetraazamacrocycles, and the reactivity order in the O 2-transfer reactions was the same as that observed in the aldehyde oxidation reactions. © 2010 American Chemical Society.
DOI
10.1021/ja107177m
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자연과학대학 > 화학·나노과학전공 > Journal papers
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