title: Homogeneous Photocatalytic Water Oxidation with a Dinuclear Co(III)-Pyridylmethylamine Complex.
abstract: A bis-hydroxo-bridged dinuclear Co(III)-pyridylmethylamine complex (1) was synthesized and the crystal structure was determined by X-ray crystallography. Complex 1 acts as a homogeneous catalyst for visible-light-driven water oxidation by persulfate (S2O8(2-)) as an oxidant with [Ru(II)(bpy)3](2+) (bpy = 2,2'-bipyridine) as a photosensitizer affording a high quantum yield (44%) with a large turnover number (TON = 742) for O2 formation without forming catalytically active Co-oxide (CoO(x)) nanoparticles. In the water-oxidation process, complex 1 undergoes proton-coupled electron-transfer (PCET) oxidation as a rate-determining step to form a putative dinuclear bis-μ-oxyl Co(III) complex (2), which has been suggested by DFT calculations. Catalytic water oxidation by 1 using [Ru(III)(bpy)3](3+) as an oxidant in a H2(16)O and H2(18)O mixture was examined to reveal an intramolecular O-O bond formation in the two-electron-oxidized bis-μ-oxyl intermediate, prior to the O2 evolution.
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Ishizuka
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Watanabe
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kotani
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Dachao
authors.initials: D
authors.lastname: Hong
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Satonaka
authors.affiliation: Department of Chemistry, College of Science, Rikkyo University , 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Wada
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University , Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Shiota
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University , Motooka, Nishi-ku, Fukuoka 819-0395, Japan.|Elements Strategy Initiative for Catalysts & Batteries, Kyoto University , Nishi-ku, Kyoto 615-8520, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yoshizawa
authors.affiliation: Faculty of Pharmaceutical Science at Kagawa Campus, Tokushima Bunri University , 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Ohara
authors.affiliation: Faculty of Pharmaceutical Science at Kagawa Campus, Tokushima Bunri University , 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, and ALCA, Japan Science and Technology Agency , Suita, Osaka 565-0871, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kato
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, and ALCA, Japan Science and Technology Agency , Suita, Osaka 565-0871, Japan.|Faculty of Science and Technology, Meijo University, ALCA and SENTAN, Japan Science and Technology Agency (JST) , Tempaku, Nagoya, Aichi 468-8502, Japan.|Department of Chemistry and Nano Science, Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kojima