N–O Bond Homolysis of an Iron(II) TEMPO Complex Yields an Iron(III) Oxo Intermediate

The reaction of TEMPO with the iron­(I) synthon PhB­(MesIm)3Fe­(COE) leads to formation of the κ1-TEMPO complex PhB­(MesIm)3Fe­(TEMPO). Structural and spectroscopic data establish the complex contains divalent iron bound to a nitroxido anion and is isoelectronic to an iron­(II) peroxo complex. Thermolysis of the complex results in N–O bond homolysis, leading to the formation of an iron­(III) oxo intermediate. The oxo intermediate is active in oxygen atom transfer reactions and can be trapped by the triphenylmethyl radical to give the iron­(II) alkoxo complex PhB­(MesIm)3Fe­(OCPh3).