H2O2 activation with biomimetic non-haem iron complexes and AcOH: connecting the g=2.7 EPR signal with a visible chromophore

Mechanistic studies of H2O2 activation by complexes related to [(BPMEN)Fe-II(CH3CN)(2)](2+) with electron-rich pyridines revealed that a new intermediate formed in the presence of acetic acid with a 465 nm visible band can be associated with an unusual g = 2.7 EPR signal. We postulate that this chromophore is an acylperoxoiron(III) intermediate.