Water Oxidation Reaction Mediated by an Octanuclear Iron‐Oxo Cluster

Abstract

A one‐pot synthetic procedure yields the octanuclear Fe III complex [Fe 8 (µ 4 ‐O) 4 (µ ‐ 4‐ t Bu‐pz) 12 Cl 4 ] ( 2 ). The molecular structure of 2 resembles the building units of iron‐containing minerals like magnetite, ferrihydrite and maghemite. Based on mechanistic investigation we propose that in presence of Et 3 N, iron(III) pyrazolates are reduced to iron(II) pyrazolates, which then activate dioxygen to form 2 . Complex 2 exhibits unique spectroscopic and electrochemical properties relative to those of the previously reported Fe 8 clusters based on pyrazolate ligands. Furthermore, 2 can oxidize water to hydrogen peroxide, thereby mimicking the water splitting process taking place at the surface of magnetite. Compound 2 therefore acts as both structural and functional models of iron‐containing minerals.