Spectroscopic studies on imidazole adducts of iron(III)quadridentate schiff base complexes

Abstract

Optical spectroscopy, EPR and CV studies are carried out on complexes of the type [Fe^lll(SB)(lmH)₂]X. where SB = tetradentate O₂N₂ schiff base. ImH = Imidazole and X = CI^-. CIO₄ '. When the tetradentate ligand contains a phenolate moiety the iron- imidazole interaction is found to be weak and the high-spin state of Fe(lII) is preferentially stabilized. Various ligand field parameters. such as axial/rhombic distortions and the Fe-N(lmH) bond distances have considerable influence on the Fe(III)lFe(lI) redox potential and on the rate of heterogeneous electron transfer (<em>k</em> <em>_s</em>). Correlation of magnetic moments with <em>k _s</em> indicate that high-spin complexes have faster rates of electron transfer in comparison with those of low-spin complexes.