Thermodynamic Characteristics of the Resolvation of Glycylglycinate Ions and Their Contribution to the Change in Stability of Complexes with Cu(II) and Ni(II) in Aqueous–Organic Solvents

Thermodynamic characteristics (∆ G , ∆ Н , T ∆ S ) of the resolvation of glycylglycine and its protonated and deprotonated forms in aqueous solutions of ethanol and dimethylsulfoxide are presented experimentally and calculated on the basis of original and literature data. The change in the Gibbs energy of the reactions of the formation of nickel(II) and copper(II) glycylglycinate complexes in water-ethanol and water-dimethylsulfoxide solvents is considered, and the solvation contributions of the reagents to the change in the stability of complex particles are estimated. Features of the changes in the thermodynamic characteristics of the solvation and complexing of glycylglycinate ions with d -metals in aqueous–organic mixtures are described.