Intramolecular C–H and C–F Bond Oxygenation Mediated by a Putative Terminal Oxo Species in Tetranuclear Iron Complexes

Herein
we report the intramolecular arene C–H and C–F
bond oxygenation by tetranuclear iron complexes. Treatment of [LFe3(PhPz)3OFe]­[OTf]2 (1) or
its fluorinated analog [LFe3(F2ArPz)3OFe]­[OTf]2 (5) with iodosobenzene results
in the regioselective hydroxylation of a bridging pyrazolate ligand,
converting a C–H or C–F bond into a C–O bond.
The observed reactivity suggests the formation of terminal and reactive
Fe-oxo intermediates. With the possibility of intramolecular electron
transfer within clusters in 1 and 5, different
reaction pathways (FeIV-oxo vs FeIII-oxo) might
be responsible for the observed arene hydroxylation.