Mixed-Ligand Complexes of Some Divalent Transition Metal Ions with Dicarboxylic Amino Acids and 8-Hydroxyquinoline

Abstract

Mixed-ligand complexes of CoII, NiII, and CuII with dicarboxylic amino acids (aspartic and glutamic or H2ADA) as primary ligands and 8-hydroxyquinoline as a secondary ligand were prepared and characterized. Formation constants of the different complexes were determined acidimetrically at 25 °C and at ionic strength I = 0.1 mol dm-3 (KNO3) and were discussed in terms of the nature of both the metal ion and the ligand used. The thermodynamic functions (ΔH, ΔG°, and ΔS°) associated with the formation of [MII + (HADA)1- + 8-hydroxyquinoline] complexes were also calculated and discussed.