Trinuclear Nickel Catalyst for Water Oxidation: Intramolecular Proton- Coupled Electron Transfer Triggered Trimetallic Cooperative O-O Bond Formation

We report a molecular trinuclear nickel (TNC-Ni) catalyst for water oxidation that exhibited high catalytic performance and stability under neutral conditions (pH 7). Electrochemical studies disclosed that cooperation among the three nickel sites plays a vital role in both charge accumulation and O-O bond formation. This TNC-Ni catalyst could accomplish 4e(-) oxidation of water by involving all three nickel sites and the O-O bond formation was triggered by a charge distribution process from 5 to 5dp via proton-coupled electron transfer.