Equilibrium Study of the Mixed Complexes of Copper(II) with Adenine and Amino Acids in Aqueous Solution

Abstract

In the present study, the protonation constants of adenine (Ade), a DNA base, and of the amino acids aspartic acid, glutamic acid, asparagine, leucine, phenylalanine and tryptophan, were determined in 0.1 mol·L−1 KNO3 ionic medium and at 25.00 °C by the potentiometric method. The binary and ternary ligand complex systems that Cu(II) establishes with Ade and these amino acids were examined using the same method and in the same ionic medium; stability constants were calculated with the BEST computer software and distribution curves were drawn by means of the SPE software. The relative stability of each ternary complex was compared with that of the corresponding binary complexes in terms of their ∆log10K values.