Spin State Differentiated [3Fe-4S] Cluster Electrocatalyzes Water Oxidation Efficiently.

Abstract

Though there are many synthetic iron-sulfur clusters that have been reported to show catalytic activity mimicking the natural cofactors in metalloenzymes, the influence of the spin state on the catalytic property is seldom touched. Here, a disulfide-bridged triiron(II) complex is shown, namely [Fe₃(Sip)₄][CF₃SO₃]₂ (Fe₃(Sip)₄, HSip = sulfanylpropyliminomethyl-pyridine), can efficiently electrocatalyze water oxidation with a turnover frequency of 932 s^-1 and Faraday efficiency of 86%, better than many iron-based catalysts. More importantly, the terminal low-spin (S = 0) iron(II) sites possessing a N4S2 first coordination environment, along with the synergetic catalysis of ligands, play a crucial role in the catalytic process. This research highlights the unconventional applications of iron-sulfur clusters in electrocatalytic water oxidation and underlines a promising avenue for developing innovative catalysts.