Potentiometric studies on mixed-ligand complexes of copper(II) and zinc(II) with some amino acids (glycine, DL-?-alanine and DL-valine) as primary ligands and imidazole as a secondary ligand

Abstract

Mixed-ligand complexes of CuII and ZnII with glycine(GL), DL-α-alanine (AL) and DL-valine (VL) as primary ligands and imidazole (IM) as secondary ligand have been studied potentiometrically under physiological conditions (t=37° C and I=0.15 M KNO3). The experimental pH-titration data were analysed with aid of the SUPERQUAD computer program in order to evaluate formation constants of binary and ternary systems involying amino acids (AA) and IM. The relative stability of each of the ternary complexes was compared with that of corresponding binary complexes in terms of Δ log K and log X values.