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Dioxygen activation at a single copper site: structure, bonding, and mechanism of formation of 1:1 Cu-O2 adducts.
- Source :
-
Journal of the American Chemical Society [J Am Chem Soc] 2004 Dec 29; Vol. 126 (51), pp. 16896-911. - Publication Year :
- 2004
-
Abstract
- To evaluate the fundamental process of O(2) activation at a single copper site that occurs in biological and catalytic systems, a detailed study of O(2) binding to Cu(I) complexes of beta-diketiminate ligands L (L(1) = backbone Me; L(2) = backbone tBu) by X-ray crystallography, X-ray absorption spectroscopy (XAS), cryogenic stopped-flow kinetics, and theoretical calculations was performed. Using synchrotron radiation, an X-ray diffraction data set for L(2)CuO(2) was acquired, which led to structural parameters in close agreement to theoretical predictions. Significant Cu(III)-peroxo character for the complex was corroborated by XAS. On the basis of stopped-flow kinetics data and theoretical calculations for the oxygenation of L(1)Cu(RCN) (R = alkyl, aryl) in THF and THF/RCN mixtures between 193 and 233 K, a dual pathway mechanism is proposed involving (a) rate-determining solvolysis of RCN by THF followed by rapid oxygenation of L(1)Cu(THF) and (b) direct, bimolecular oxygenation of L(1)Cu(RCN) via an associative process.
Details
- Language :
- English
- ISSN :
- 0002-7863
- Volume :
- 126
- Issue :
- 51
- Database :
- MEDLINE
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 15612729
- Full Text :
- https://doi.org/10.1021/ja045678j