The catalyticwater oxidation activity of mononuclear ruthenium complexes comprising a pyridine-functionalized abnormal triazolylidene ligand can be adjusted by modification of the triazolylidene substituents, which is readily achieved through click-type cycloaddition chemistry, affording some of the most active ruthenium catalysts known thus far for water oxidation (TONs > 400, TOFs close to 7000 h⁻¹).

Combined kinetic & in operando spectroscopic studies, factor analysis, and DFT calculations provide insight into the water oxidation reaction catalyzed by operationally homogeneous iridium mesoionic carbene complexes.