Coordination properties of tridentate ( N, O, O) heterocyclic alcohol (PDC) with Cu(II) : Mixed ligand complex formation reactions of Cu(II) with PDC and some bio-relevant ligands

Abstract

The formation equilibria of copper(II) complexes and the ternary complexes Cu(PDC)L (PDC = 2,6-bis-(hydroxymethyl)-pyridine, HL = amino acid, amides or DNA constituents) have been investigated. Ternary complexes are formed by a simultaneous mechanism. The results showed the formation of Cu(PDC)L, Cu(PDC, H −1)(L) and Cu(PDC, H −2)(L) complexes. The concentration distribution of the complexes in solution is evaluated as a function of pH. The effect of dioxane as a solvent on the protonation constant of PDC and the formation constants of Cu(II) complexes are discussed. The thermodynamic parameters Δ H ° and Δ S ° calculated from the temperature dependence of the equilibrium constants are investigated.