Molecular Mechanism of the Mononuclear Copper Complex‐Catalyzed Water Oxidation from Cluster‐Continuum Model Calculations

Abstract

Cluster-continuum model calculations were conducted to decipher the mechanism of water oxidation catalyzed by a mononuclear copper complex. Among various OÀ O bond formation mechanisms investigated in this study, the most favorable pathway involved the nucleophilic attack of OH À onto the * + LÀ Cu II À OH À intermediate. During such process, the initial binding of OH À to the proximity of * + LÀ Cu II À OH À would result in the spontaneous oxidation of OH À , leading to OH * radical and Cu II À OH À species. The further OÀ O coupling between OH * radical and Cu II À OH À was associated with a barrier of 14.8 kcal mol À 1 , leading to the formation of H 2 O 2 intermediate. Notably, the formation of "Cu III À O *À " species, a widely proposed active species for OÀ O bond formation, was found to be thermodynamically unfavorable and could be bypassed during the catalytic reactions. On the basis the present calculations, a catalytic cycle of the mononuclear copper complex-catalyzed water oxidation was proposed.

Deciphering the active species and reaction mechanism in water oxidation catalyzed by a copper complex with redox-active ligands

“…Given the complexities at the mechanistic level, it is crucial to elucidate the reaction mechanism of Cu-based water oxidation catalysts through theoretical calculations. 26,27,29,33 These insights offer valuable information for the future design and development of novel copper-based water oxidation catalysts (WOCs).…”

“…In particular, concerning copper-based catalysts, 26,27 the active intermediate in their catalytic cycle has been identified as M-oxyl. Notably, the active intermediate is identified as an M-oxyl complex 28,29 instead of an M-oxo complex.…”