Coordination geometries and cooperative ordering effects in copper(II) complexes with tridentate schiff base dianions—II. EPR study on N-salicylideneglycinatocopper(II) complexes with imidazole derivatives
摘要:
N-salicylideneglycinatocopper(II) complexes of the composition Cu(salgly) (L)(H2O)(x) were synthesized with L = 1-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, benzimidazole; and x = 0, 1 or 2. According to the results of ligand-field and EPR spectra, the coordination polyhedra around copper(II) exhibit geometries ranging from square-pyramidal to square-planar. The water of crystallization and the substituents on the imidazole ligand, moreover, remarkably influence cooperative ordering effects. A variety of coupling patterns between ferrodistortive and antiferrodistortive is observed. In some cases enhancement of the EPR measuring frequency from 9 to 35 GHz results in partial decoupling of the systems.