A Synthetic Model for the Possible Fe2IV(μ-O)2 Core of Methane Monooxygenase Intermediate Q Derived from a Structurally Characterized FeIIIFeIV(μ-O)2 Complex

A bis(mu-oxo)diiron(IV,IV) complex as a model for intermediate Q in the methane monooxygenase reaction cycle has been prepared. The precursor complex with a [(FeFeIV)-Fe-III(mu-O)(2)] core was fully characterized by X-ray crystallography and other spectroscopic analyses and was converted to the [Fe-2(IV)(mu-O)(2)] complex via electrochemical oxidation at 1000 mV (vs Ag/Ag+) in acetone at 193 K. The UV-vis spectral features, Mossbauer parameters (Delta E-Q = 2.079 mm/s and delta = -0.027 mm/s), and EXAFS analysis (Fe-O/N = 1.73/1.96 angstrom and Fe center dot center dot center dot Fe = 2.76 angstrom) support the structure of the low-spin (S = 1, for each Fe) [Fe-2(IV)(mu-O)(2)] core. The rate constants of the hydrogen abstraction reaction from 9,10-dihydroanthracene at 243 K suggest the high reactivity of these synthetic bis(mu-oxo)diiron complexes supported by simple N4 tripodal ligand.

Automated summary

In this study, a bis(mu-oxo)diiron(IV,IV) complex was synthesized as a model for intermediate Q in the methane monooxygenase reaction cycle. The structure of the complex was characterized by X-ray crystallography and spectroscopic techniques, and its high reactivity was demonstrated through hydrogen abstraction reactions.