Thermodynamic and NMR studies of mixed-ligand complex formation of mercury (II) ethylenediaminetetraacetate with dipeptides in solution

pH-potentiometry, calorimetry and 1Н and 13С NMR spectroscopy have been used to study the mixed-ligand complex formation in the systems Hg2+–Edta4−–L− (L = GlyGly, AlaAla) in aqueous solution at 298.15 K and ionic strength of I = 0.5 (KNO3). The thermodynamic parameters of formation of the HgEdtaL3−, and HgEdtaLH - 1 4 - complexes have been determined. The most probable coordination mode for the complexone and the dipeptide in the mixed-ligand complexes was discussed.