Activation of a Non-Heme FeIII-OOH by a Second FeIII 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 degrees 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.