title: Base-enhanced catalytic water oxidation by a carboxylate-bipyridine Ru(II) complex.
abstract: In aqueous solution above pH 2.4 with 4% (vol/vol) CH3CN, the complex [Ru(II)(bda)(isoq)2] (bda is 2,2'-bipyridine-6,6'-dicarboxylate; isoq is isoquinoline) exists as the open-arm chelate, [Ru(II)(CO2-bpy-CO2(-))(isoq)2(NCCH3)], as shown by (1)H and (13)C-NMR, X-ray crystallography, and pH titrations. Rates of water oxidation with the open-arm chelate are remarkably enhanced by added proton acceptor bases, as measured by cyclic voltammetry (CV). In 1.0 M PO4(3-), the calculated half-time for water oxidation is ∼7 μs. The key to the rate accelerations with added bases is direct involvement of the buffer base in either atom-proton transfer (APT) or concerted electron-proton transfer (EPT) pathways.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290.
authors.forename: Na
authors.initials: N
authors.lastname: Song
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290.
authors.forename: Javier J
authors.initials: JJ
authors.lastname: Concepcion
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Binstead
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Rudd
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290.
authors.forename: Aaron K
authors.initials: AK
authors.lastname: Vannucci
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Dares
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Coggins
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290 tjmeyer@unc.edu.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Meyer
keywords: Ru polypyridyl complexes; electrocatalysis; solar energy; water oxidation catalysis; water splitting
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