The formation of proton and alkali metal complexes with ligands of biological interest in aqueous solution. Thermodynamics of Li+, Na+ and K+-dicarboxylate complex formation

The formation and stability of Li⁺, Na⁺ and K⁺ complexes with oxalate, malonate, succinate, maleate, DL-malate and phthalate were studied potentiometrically at various ionic strengths. From the data thus obtained, as well as from several literature data on the protonation of the above-mentioned ligands in various ionic media and at various temperatures, the dependence of Na⁺ and K⁺ complex formation on temperature was determined. The dependence on ionic strength, both for the protonation and the complex formation, is also discussed.