Probing Ligand Effects on O–O Bond Formation of Ru-Catalyzed Water Oxidation: A Computational Survey

Ligand effects of some representative monomeric Ru-based water oxidation catalysts on the key O–O formation step are revealed in this work. Three effects, namely, cis-effect, net charge effect, and steric hindrance effect, are identified, which can exert sizable modulation on the O–O formation barriers for the two widely accepted O–O formation mechanisms of WNA (water nucleophilic attack) and I2M (direct coupling of two high-valent metal oxo units). The study demonstrates that, through the way of ligand design, there remains a large space for improving O–O bond formation reactivity.