Complexes of divalent ions in mixed solvent media. III. Outer-sphere interactions in amine + diluent solutions

Abstract

The standard enthalpies and (in part) free energies and entropies of transfer from amine (L) to amine + diluent (D) mixtures have been determined for MX2L2 complexes at 25°C using chloroform, 1,1,2,2,-tetrachloroethane (TCE), benzene, chlorobenzene, and ethyl acetate as diluents (M=Co and Zn; X=Cl and Br; L = pyridine, α-picoline, and γ-picoline). Thermodynamic functions of transfer indicate specific outer-sphere interactions of the complexes with amine and protic diluents (chloroform and TCE) and reveal solvent-solvent interactions of amine + protic diluent mixtures. The effects of the nature of X, L, and M of the MX2L2 complexes on their interaction with the components of the mixed solvent are discussed.