Regularities in the influence of aqueous-organic solvents on thermodynamics of complexing reactions. Communication 2. Enthalpy and entropy changes upon the formation of ammine and carboxylate complexes

On the basis of results of previously conducted thermochemical studies the dynamics of enthalpy and entropy contributions into displacement of equilibria of d-metal ions complexing in aqueous-organic solvents was considered. It is shown that increase in stability of cadmium(2) ethylenediamine complexes in aqueous solutions of ethanol at all stages of coordination occurs largely due to the entropy contribution. Insignificant value of the enthalpy contribution during formation of cadmium monoligand complex stems from the fact that differences in the enthalpy characteristics of the central ion and complex solvation in the solutions are approximately equal to the change in ligand transfer enthalpy, taken with the opposite sign