Axial Ligand Effects of Ru‐BDA Complexes in the O–O Bond Formation via the I2M Bimolecular Mechanism in Water Oxidation Catalysis

Abstract

A detailed computational investigation of the mechanistic aspects of the water oxidation catalysis (WOC) for ruthenium‐based catalysts [Ru(bda)(isoq) 2 ] (H 2 bda = 2,2′‐bipyridine‐6,6′‐dicarboxylic acid; isoq = isoquinoline). Density functional theory (DFT) calculations describe the kinetics by means of the energy barrier that leads to the O–O coupling, the rate‐limiting step for WOC. To test the effect of the axial ligand environment, we investigated bda complexes with para ‐substituted isoquinolines, phthalazines and pyridines. Since previous screening analyses of the potential energy surface revealed a face to face orientation of metal‐oxo species to be best for facilitating the O–O bond formation, this paper probes the deeper role of the axial ligands that saturate the Ru(bda) based complexes from a computational point of view.