Reaction of NN′-ethylenebis(thiosalicylideneiminato)iron(II) with dioxygen. Formation of a µ-peroxo-intermediate and isolation of a µ-oxo-complex with the unusual S=½ spin state

Abstract

The complex of NN′-ethylenebis(thiosalicyl-ideneiminato)iron(II), Fe(Ssalen)(magnetic moment of 1·90 B.M. at 295 K) was treated with dioxygen in pyridine solution at room temperature to yield the µ-oxo-compound [Fe(Ssalen)]2O.pyridine via an oxygen complex whose formation could be reversed at higher temperatures (e.s.r. measurements and the stoicheiometry of the oxygen reaction suggest that the latter compound is a peroxo-bridged species); the µ-oxo-complex contains Fe in the unusual S=½ spin state and displays weak antiferro-magnetic coupling.