Design of a dinuclear ruthenium based catalyst with a rigid xanthene bridge for catalytic water oxidation

• Development of a dinuclear ruthenium complex for probing catalytic water oxidation
• Kinetic studies revealed a first-order reaction mechanism.
• The results implied a water nucleophilic attack pathway for OO bond formation.

A new dinuclear ruthenium complex 1 (L1[Ru(bda)2(picoline)]2) based on Ru–bda (H2bda = 2,2′-bipyridine-6,6′-dicarboxylic acid) and dipyridyl xanthene (L1 = 4,5-dipyridyl-2,7-di-tert-butyl-9,9-dimethyl xanthene) ligand was synthesized to probe the catalytic oxidation of water. An oxygen evolution experiment displays a low catalytic water oxidation activity with a first-order reaction kinetic mechanism. The result indicates that the OO bond formation of the dinuclear catalyst 1 follows a water nucleophilic attack pathway rather than a radical coupling pathway. The most plausible interpretation is that the steric hindrance effects of the L1 and bda ligands lead to a disadvantage in forming the face-to-face configuration of the two active sites in a one dimer molecule.

A new dinuclear ruthenium complex 1 was synthesized to probe the catalytic oxidation of water. An oxygen evolution experiment displays a low catalytic water oxidation activity with a first-order reaction kinetic mechanism. The result indicates that the OO bond formation of the dinuclear catalyst 1 follows a water nucleophilic attack pathway rather than a radical coupling pathway.Figure optionsDownload as PowerPoint slide