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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 ?s. 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.

SUBMITTER: Song N

PROVIDER: S-EPMC4413278 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

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Base-enhanced catalytic water oxidation by a carboxylate-bipyridine Ru(II) complex.

Song Na N Concepcion Javier J JJ Binstead Robert A RA Rudd Jennifer A JA Vannucci Aaron K AK Dares Christopher J CJ Coggins Michael K MK Meyer Thomas J TJ

Proceedings of the National Academy of Sciences of the United States of America 20150406 16

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 wat ...[more]

PMID: 25848035

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