Clear Evidence Showing the Robustness of a Highly Active Oxygen-evolving Mononuclear Ruthenium Complex with an Aqua Ligand

Experiments show that [Ru(terpy)(bpy)(OH2)]2+ is highly active as a catalyst toward oxidation of water into molecular oxygen in spite of the mononuclear character of the complex, while [Ru(terpy)(bpy)Cl]+ shows no activity at all. It is also confirmed that [Ru(terpy)(bpy)(OH2)]2+ is fairly stable under strongly oxidizing conditions in the presence of cerium(IV) ammonium nitrate, Ce(NH4)2(NO3)6, which was evidenced by spectrophotometric, mass spectrometric, and gas chromatographic analysis.