Formation of the syn isomer of [FeIV(Oanti)(TMC)(NCMe)]2+ in the reaction of Lewis acids with the side-on bound peroxo ligand in [FeIII(η2-O2)(TMC)]+

Abstract

We demonstrate that the reactions of [Fe^III(η²-O₂)(TMC)]⁺ (TMC = tetramethylcyclam) with Lewis acids (H⁺ and NO⁺) afford the recently described syn isomer of [Fe^IV(O)(TMC)(NCMe)]²⁺ (and not the anti isomer as had been tacitly assumed). This outcome is a logical consequence of the fact that the side-on peroxo ligand is bound to the syn face of the Fe(TMC) unit in the precursor.