A diiron(IV) complex that cleaves strong C-H and O-H bonds

The controlled cleavage of strong C-H bonds such as those of methane poses a significant and industrially important challenge for chemists. In nature, methane is oxidized to methanol by soluble methane monooxygenase via a diiron(IV) intermediate called Q. However, the only two reported diiron(IV) complexes have activities towards C-H bonds that fall far short of the activity of this biological catalyst. In this paper, we model the chemistry of MMO-Q by generating an oxo-bridged diiron(IV) complex by electrochemical oxidation. This species is a more effective oxidant. It can attack C-H bonds as strong as 100 kcal mol(-1) and reacts with cyclohexane 100- to 1,000-fold faster than mononuclear Fe(IV)=O complexes of closely related ligands. Strikingly, this species can also cleave the strong O-H bonds of methanol and t-butanol instead of their weaker C-H bonds, representing the first example of O-H bond activation for iron complexes.