The cis-[RuII(bpy)2(H2O)2]2+ water-oxidation catalyst revisited

The only operating mechanism in the oxidation of water to dioxygen catalyzed by the mononuclear cis-[Ru^II(bpy)₂(H₂O)₂]²⁺ complex when treated with excess Ce^IV was unambiguously established. Theoretical calculations together with ¹⁸O-labeling experiments (see plot) revealed that it is the nucleophilic attack of water on a RuO group.