High Oxidation State Iridium Mono-μ-oxo Dimers Related to Water Oxidation Catalysis

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• 作者：Liam S. Sharninghausen ; Shashi Bhushan Sinha ; Dimitar Y. Shopov ; Bonnie Choi ; Brandon Q. Mercado ; Xavier Roy ; David Balcells ; Gary W. Brudvig ; Robert H. Crabtree
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：December 14, 2016
• 年：2016
• 卷：138
• 期：49
• 页码：15917-15926
• 全文大小：552K
• ISSN：1520-5126

文摘

The highly active iridium “blue solution” chemical and electrochemical water oxidation catalyst obtained from Cp*IrL(OH) precursors (L = 2-pyridyl-2-propanoate) has been difficult to characterize as no crystal structure can be obtained because of the multiplicity of geometrical isomers present. Other data suggest complete loss of the Cp* ligand and the formation of a LIr-O-IrL unit. We have now developed a route to a series of well-defined Ir(IV,IV) mono-μ-oxo dimers, containing the closely related L₂Ir-O-IrL₂ unit. Unlike the catalyst, these model compounds are separable by silica gel chromatography and readily form single crystals. We report three stereoisomers with the formula ClL₂Ir-O-IrL₂Cl, which are fully characterized, including by X-ray crystallography, and are compared to the “blue solution”. To the best of our knowledge, these species represent the first examples of structurally characterized dinuclear μ-oxo Ir(IV,IV) compounds without metal–carbon bonds.