Solvation of copper(I) and stability of its complex with cryptand 222 in dimethyl sulfoxide–acetonitrile mixtures

Abstract

Stability constants of copper(I) complex with cryptand 222 in acetonitrile (AN) and in its mixtures with dimethyl sulfoxide (DMSO) have been derived from potentiometric measurements at 25 °C. The experimentally evaluated stability constants of the Cu+222 cryptate, K, have been correlated with the mixed solvent composition with the use of a coordination model of solvation. The correlation parameters βi, which may be assigned to the overall formation constants of the copper(I) solvato-complex: Cu+(AN)4+i DMSO [graphic omitted] Cu+(AN)4–i(DMSO)i+i AN have been found from a curve-fitting procedure to be: log β1= 0.44, log β2=–0.05, log β3=–0.61 and log β4=–2.13. The value of log β4 has been used for calculations of Cu+222 stability in pure DMSO.