Exchange interactions in some binuclear iron(III)complexes studied by EPR

The binuclear iron(III) complexes have been the subject of widespread study1–8, mainly by use of magnetic susceptibility measurements, because of their unusual magnetic properties. Among dimeric iron compounds, especially interesting features are exhibited by complexes containing an Fe-O-Fe bridge. The oxygen bridge is not confined only to dimeric iron compounds8–10, and thus EPR has been applied to the problem of recognizing such structures and the role of iron in bridge systems. One example of this is the attempt11 to recognize complexes of FeIII with HEDTA1, and the quintet state spectrum was obtained. The spin Hamiltonian parameter values D and E were not calculated precisely, because of the lack of data relating to resonance field angular dependence.