title: High Oxidation State Iridium Mono-μ-oxo Dimers Related to Water Oxidation Catalysis.
abstract: 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-IrL2unit. 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.
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
authors.forename: Liam S
authors.initials: LS
authors.lastname: Sharninghausen
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
authors.forename: Shashi Bhushan
authors.initials: SB
authors.lastname: Sinha
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
authors.forename: Dimitar Y
authors.initials: DY
authors.lastname: Shopov
authors.affiliation: Department of Chemistry, Columbia University , New York, New York 10027, United States.
authors.forename: Bonnie
authors.initials: B
authors.lastname: Choi
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
authors.forename: Brandon Q
authors.initials: BQ
authors.lastname: Mercado
authors.affiliation: Department of Chemistry, Columbia University , New York, New York 10027, United States.
authors.forename: Xavier
authors.initials: X
authors.lastname: Roy
authors.affiliation: Centre of Excellence in Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo , N-0315 Oslo, Norway.
authors.forename: David
authors.initials: D
authors.lastname: Balcells
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Brudvig
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Crabtree