Abstract

We report the FT-i.r., FT-Raman, electronic, and Mössbauer spectra for several new ?-oxo-monobridge FeIIIOFeIII compounds with acyclic tetradentate ligands. Mössbauer spectra confirm the oxidation states for these complexes. The symmetric and asymmetric stretching frequencies determined for Fe - O - Fe bonds have allowed changes to be predicted in the M - O - M angle (from 144.6 to 150.7°). The electronic absorption spectra surprisingly resemble features exhibited by the spectrum of hemerythrine. Voltammetric results in DMF with a vitreous carbon electrode reveal three one-electron reduction stages which correspond to the dimeric processes FeIII FeIII/ FeII FeIII and FeII FeIII /FeII FeII, and to the monomeric process FeII /FeI.