Stability of Copper(ii) Complexes With Cryptand[2.2.2] in Aqueous Dimethylsulfoxide Solutions

In this work, the stability constants of mononuclear, binuclear and protonated copper(II) complexes with cryptand[2.2.2] in aqueous and aqueous-dimethylsulfoxide solutions at = 298 K and μ → 0 were determined by potentiometric titration. It was found that an increase in the dimethyl sulfoxide content in solution leads to a decrease in the stability of mononuclear and protonated copper(II) cryptates and an increase in the stability of the binuclear copper(II) cryptate complex. The Gibbs energy values of the transfer of copper(II) cryptates from water to aqueous dimethylsulfoxide solvent have been calculated using our own and literature data. The solvation contributions of reagents to the change of Gibbs energy of the studied reactions have been evaluated.