A Ru-2(Ii,Iii) Diphosphonato Complex With A Metal-Metal Bond For Water Oxidation

Unlike [Ru-2(mu-O2CCH3)(4)], the structurally analogous water-soluble Ru-2(II,III) diphosphonato complex K-3[Ru-2(hedp)(2)(H2O)(2)] (K-3.1) is only involved in stoichiometric water oxidation with a maximum 67% O-2 yield under CAN/HNO3 solution (pH 1.0) for 2.5 h. The water oxidation mechanism and intermediate products were ascertained by UV-vis, ESI-MS and DFT calculation.