DIVALENT TRANSITION-METAL ION MIXED-LIGAND COMPLEXES ALIPHATIC DICARBOXYLIC-ACIDS AND IMIDAZOLES

Mixed ligand metal complexes of Co-II, Ni-II and Cu-II with dicarboxyl ic aliphatic acids, H(2)L (succinic, malic and tartaric) as primary li gands and with imidazoles, L' (imidazole and 2-methylimidazole) as sec ondary ligands were prepared and characterized. MLL(2)' and MLL(4)' mo lecular formulae were suggested for these complexes. Formation constan ts of the different complexes were determined pH-metrically at T = 25 +/- 0.1 degrees C and mu = 0.1 mol dm(-3) (NaClO4). The stability of t he mixed ligand complexes increased as the effective basicity of the d icarboxylic aliphatic acid anion increased, namely, tartarate < malate < succinate acid.