title: A nickel containing polyoxometalate water oxidation catalyst.
abstract: A new pentanickel silicotungstate complex, K(10)H(2)[Ni(5)(OH)(6)(OH(2))(3)(Si(2)W(18)O(66))]·34H(2)O (KH-), has been synthesized and characterized by X-ray crystallography and several other methods. Dynamic light scattering, kinetics and other experiments confirm that in the presence of [Ru(bpy)(3)](2+) (the photosensitizer for light-driven water oxidations) and [Ru(bpy)(3)](3+) (the oxidant in the dark water oxidations) exists in an equilibrium between solution (soluble) and a [Ru(bpy)(3)](n+)- complex (minimally soluble) form. This new pentanickel polyoxometalate catalyzes efficient water oxidation in both the dark and on irradiation with 455 nm LED light with 1.0 mM [Ru(bpy)(3)](2+) photosensitizer and 5.0 mM Na(2)S(2)O(8), sacrificial electron acceptor. Four lines of evidence indicate that in this solution [symbol:see text] Ru(bpy)(3)](n+)- complex equilibrium remains molecular and does not decompose to nickel hydroxide particles.
authors.affiliation: Department of Chemistry, Emory University, Atlanta, GA 30322, USA.
authors.forename: Guibo
authors.initials: G
authors.lastname: Zhu
authors.forename: Elliot N
authors.initials: EN
authors.lastname: Glass
authors.forename: Chongchao
authors.initials: C
authors.lastname: Zhao
authors.forename: Hongjin
authors.initials: H
authors.lastname: Lv
authors.forename: James W
authors.initials: JW
authors.lastname: Vickers
authors.forename: Yurii V
authors.initials: YV
authors.lastname: Geletii
authors.forename: Djamaladdin G
authors.initials: DG
authors.lastname: Musaev
authors.forename: Jie
authors.initials: J
authors.lastname: Song
authors.forename: Craig L
authors.initials: CL
authors.lastname: Hill