Effects of a Proximal Base on Water Oxidation and Proton Reduction Catalyzed by Geometric Isomers of [Ru(tpy)(pynap)(OH2)]2+
The importance of pendent bases in promoting proton-coupled electron-transfer (PCET) reactions with low activation barriers has been discussed for H+ reduction or H2 oxidation in MeCN by many groups. PCET is also essential for the 4eľ oxidation of water in order to mitigate charge buildup and to reduce overpotential. We investigated the redox and spectroscopic properties, and report the intriguing catalytic activity for the oxidation of H2O and the reduction of protons with geometric isomers of Ru complexes with pendent bases. While 1(OH2)2+ shows catalytic activity toward proton reduction, but not toward water oxidation, the geometric isomer, 2(OH2)2+, exhibits the opposite behavior.
Last Modified: September 13, 2012