Activation of a Non-Heme Fe^III-OOH by a Second Fe^III to Hydroxylate Strong C−H Bonds: Possible Implications for Soluble Methane Monooxygenase

Non-heme iron oxygenases contain either monoiron or diiron active sites, and the role of the second iron in the latter enzymes is a topic of particular interest, especially for soluble methane monooxygenase (sMMO). Herein we report the activation of a non-heme Fe^III-OOH intermediate in a synthetic monoiron system using Fe^III(OTf)₃ to form a high-valent oxidant capable of effecting cyclohexane and benzene hydroxylation within seconds at −40 °C. Our results show that the second iron acts as a Lewis acid to activate the iron–hydroperoxo intermediate, leading to the formation of a powerful Fe^V=O oxidant—a possible role for the second iron in sMMO.