Sc-Promoted O-O Bond Cleavage of a (μ-1,2-Peroxo)diiron(III) Species Formed from an Iron(II) Precursor and O to Generate a Complex with an Fe(μ-O) Core.

Soluble methane monooxygenase (sMMO) carries out methane oxidation at 4 °C and under ambient pressure in a catalytic cycle involving the formation of a peroxodiiron(III) intermediate () from the oxygenation of the diiron(II) enzyme and its subsequent conversion to , the diiron(IV) oxidant that hydroxylates methane. Synthetic diiron(IV) complexes that can serve as models for are rare and have not been generated by a reaction sequence analogous to that of sMMO. In this work, we show that Fe(MeNTB)(CHCN) (MeNTB = tris((1-methyl-1-benzo[d]imidazol-2-yl)methyl)amine) () reacts with O in the presence of base, generating a (μ-1,2-peroxo)diiron(III) adduct with a low O-O stretching frequency of 825 cm and a short Fe···Fe distance of 3.07 Å. Even more interesting is the observation that the peroxodiiron(III) complex undergoes O-O bond cleavage upon treatment with the Lewis acid Sc and transforms into a bis(μ-oxo)diiron(IV) complex, thus providing a synthetic precedent for the analogous conversion of to in the catalytic cycle of sMMO.