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

Cluster-continuum model calculations were conducted to decipher the mechanism of water oxidation catalyzed by a mononuclear copper complex. Among various O-O bond formation mechanisms investigated in this study, the most favorable pathway involved the nucleophilic attack of OH- onto the L center dot+-Cu-II-OH- intermediate. During such process, the initial binding of OH- to the proximity of L center dot+-Cu-II-OH- would result in the spontaneous oxidation of OH-, leading to OH center dot radical and Cu-II-OH- species. The further O-O coupling between OH center dot radical and Cu-II-OH- was associated with a barrier of 14.8 kcal mol(-1), leading to the formation of H2O2 intermediate. Notably, the formation of Cu-III-O center dot- species, a widely proposed active species for O-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.

Automated summary

Cluster-continuum model calculations were used to investigate the mechanism of water oxidation catalyzed by a mononuclear copper complex. The most favorable pathway involved the nucleophilic attack of OH- onto the L center dot+-Cu-II-OH- intermediate. A catalytic cycle for the mononuclear copper complex-catalyzed water oxidation was proposed based on the calculations.