Metal-Complexes As Ligands to Generate Asymmetric Homo- and Heterodinuclear MAIIIMBII Species: a Magneto-Structural and Spectroscopic Comparison of Imidazole-N versus Pyridine-N

Ten hetero- and homodinuclear MAIIIMBIII complexes, 1−10, containing the metal centers FeIIIZnII (1), FeIIICuII (2), FeIIINiII (3), FeIIIFeII (4), FeIIIMnII (5), CrIIINiII (6), CrIIIZnII (7), GaIIINiII (8), CoIIIFeII (9), and MnIIIMnII (10) are described. The tridentate ligation property of the divalent metal complexes tris(1-methylimidazole-2-aldoximato)metal(II) with three facially disposed pendent oxime O-atoms has been utilized to generate the said complexes. Complexes were characterized by various physical methods including MS, IR, UV−vis, Mossbauer and EPR spectroscopy, cyclic voltammetry (CV), variable-temperature (2−290 K) magnetic susceptibility, and X-ray diffraction techniques. Binuclear complexes 1−10 contain three oximato anions as bridging ligands and are isostructural in the sense that they all contain a metal(III) ion, LMAIII (L = 1,4,7-trimethyl-1,4,7-triazacyclononane), in a distorted octahedral environment MAIIIN3O3 and a second six-coordinated divalent metal ion, MBII, in a trigonally ...