Base-enhanced catalytic water oxidation by a carboxylate-bipyridine Ru(II) complex
Article
Song, N, Concepcion, JJ, Binstead, RA et al. (2015). Base-enhanced catalytic water oxidation by a carboxylate-bipyridine Ru(II) complex
. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 112(16), 4935-4940. 10.1073/pnas.1500245112
Song, N, Concepcion, JJ, Binstead, RA et al. (2015). Base-enhanced catalytic water oxidation by a carboxylate-bipyridine Ru(II) complex
. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 112(16), 4935-4940. 10.1073/pnas.1500245112
In aqueous solution above pH 2.4 with 4% (vol/vol) CH3CN, the complex [RuII(bda)(isoq)2] (bda is 2,2′-bipyridine-6,6′-dicarboxylate; isoq is isoquinoline) exists as the open-arm chelate, [RuII(CO2-bpy-CO2-)(isoq)2(NCCH3)], as shown by 1H and 13C-NMR, X-ray crystallography, and pH titrations. Rates of water oxidation with the open-arm chelate are remarkably enhanced by added proton acceptor bases, asmeasured by cyclic voltammetry (CV). In 1.0 M PO43-, 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.
