Spectroscopic and Electronic Structure Studies of Phenolate Cu(II) Complexes: Phenolate Ring Orientation and Activation Related to Cofactor Biogenesis

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• 作者：Somdatta Ghosh ; Jordi Cirera ; Michael A. Vance ; Tetsuya Ono ; Kiyoshi Fujisawa ; Edward I. Solomon
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：December 3, 2008
• 年：2008
• 卷：130
• 期：48
• 页码：16262-16273
• 全文大小：623K
• 年卷期：v.130,no.48(December 3, 2008)
• ISSN：1520-5126

文摘

A combination of spectroscopies and DFT calculations have been used to define the electronic structures of two crystallographically defined Cu^II-phenolate complexes. These complexes differ in the orientation of the phenolate ring which results in different bonding interactions of the phenolate donor orbitals with the Cu^II, which are reflected in the very different spectroscopic properties of the two complexes. These differences in electronic structures lead to significant differences in DFT calculated reactivities with oxygen. These calculations suggest that oxygen activation via a Cu^I phenoxyl ligand-to-metal charge transfer complex is highly endergonic (>50 kcal/mol), hence an unlikely pathway. Rather, the two-electron oxidation of the phenolate forming a bridging Cu^II peroxoquinone complex is more favorable (11.3 kcal/mol). The role of the oxidized metal in mediating this two-electron oxidation of the coordinated phenolate and its relevance to the biogenesis of the covalently bound topa quinone in amine oxidase are discussed.