Formation of the syn isomer of [Fe(IV)(Oanti)(TMC)(NCMe)](2+) in the reaction of Lewis acids with the side-on bound peroxo ligand in [Fe(III)(η(2)-O2)(TMC)](.).

Abstract

We demonstrate that the reactions of [Fe(III)(η(2)-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.