An Iron(II)[1,3-bis(2′-pyridylimino)isoindoline] Complex as a Catalyst for Substrate Oxidation with H2O2 - Evidence for a Transient Peroxidodiiron(III) Species

The complex [Fe(indH)(solvent)(3)](ClO4)(2) (1) has been isolated from the reaction of equimolar amounts of 1,3-bis(2-pyridylimino)isoindoline (indH) and Fe(ClO4)(2) in acetonitrile and characterized by X-ray crystallography and several spectroscopic techniques. It is a suitable catalyst for the oxidation of thioanisoles and benzyl alcohols with H2O2 as the oxidant. Hammett correlations and kinetic isotope effect experiments support the involvement of an electrophilic metal-based oxidant. A metastable green species (2) is observed when 1 is reacted with H2O2 at -40 degrees C and has a Fe-III(-O)(-O-2)Fe-III core on the basis of UV/Vis, electron paramagnetic resonance, resonance Raman, and X-ray absorption spectroscopic data.