Heterobimetallic NiFe Cooperative Molecular Water Oxidation Catalyst

Abstract

We reported herein the development of heterobimetallic NiFe molecular platform to understand NiFe synergistic effect in water oxidation catalysis. Compared to homonuclear bimetallic compounds (NiNi and FeFe), NiFe complex possesses more remarkable catalytic water oxidation performance. Mechanistic studies suggest that this remarkable difference is attributed to the fact that NiFe synergy can effectively promote O−O bond formation. The generated NiIII(μ‐O)FeIV=O is the key intermediate and O−O bond was formed via intramolecular oxyl‐oxo coupling between bridged O radical and terminal FeIV=O moiety.

Added Complexity!—Mechanistic Aspects of Heterobimetallic Complexes for Application in Homogeneous Catalysis

“…Here, the radical character of the oxygen is maintained, and thus the rate-determining oxyl-oxo coupling can occur. This pathway echoes the important role of lattice oxygen in heterogeneous NiFe catalysts [ 140 , 141 ].…”

“…Additionally, the sterically hindered ligand system induces orthogonal chemoselectivity compared with a conventional Ni catalyst Here, the radical character of the oxygen is maintained, and thus the rate-determining oxyl-oxo coupling can occur. This pathway echoes the important role of lattice oxygen in heterogeneous NiFe catalysts [140,141]. Hong and coworkers developed a series of heterobimetallic Ir III -based metal complexes, most notable among them the [Ni II ;Ir III ] complex depicted in Scheme 21.…”