Thermodynamics of Mixed Ligand Complex Formation of Copper(II) and Nickel Ions with Glycine and Histidine in Solution

Mixed ligand complexes of copper(II) and nickel(II) with glycine (Gly) and histidine (His) have been studied in aqueous solution using calorimetric, potentiometric and spectrophotometric data at 298.15 K and the ionic strength of I = 0.5 mol·L–1 (KNO3). The thermodynamic parameters of formation of various mixed complexes have been determined. The probable coordination modes of amino acid residues in mixed ligand complexes is discussed.