Solvent Effects on Cryptand (222) Complexation

The Role of Reactant Adsorption in the Electrode Reactions of Tl(2,2,2)+ Cryptate Complexes at Mercury Electrodes

“…Among them, the complexation reactions of thallium(I) by macrocyclic ligands in different solvents were often studied. The stability constants of the resulting complexes were determined potentiometrically [1 ± 5] or by using voltammetric methods [6,7]. It was found that in water and organic solvents Tl ion forms with cryptand (2,2,2) stable 1 : 1 inclusion complex and the solvent properties exert important influence on this complex formation reaction.…”

“…Though the reduced state in PC was described as Tl(2,2,2) 0 one may expect that also in this case the thallium amalgam is formed as a final product of the cathodic reaction. In aqueous solutions the Tl(2,2,2) was found to be reversibly reduced on the mercury electrode and its adsorption on the electrode was not reported [6,7]. However rather strong adsorption of cryptand (2,2,2) on the mercury electrode from aqueous solutions was found [9] in the presence of Na cations.…”

Stability of the Nonactin-K+ Complex in Aprotic Media

“…Thus, the solvent change of the logK s values should be treated as chiefly limited by the free energy of K + solvation, comparably to what was shown for other macrocyclic complexes [5,22,23,26]. Thus, the solvent change of the logK s values should be treated as chiefly limited by the free energy of K + solvation, comparably to what was shown for other macrocyclic complexes [5,22,23,26].…”