SOLVATION OF COBALT(II), TRIFLUOROMETHANESULFONATE AND PERCHLORATE IONS IN ACETONITRILE-METHANOL MIXTURES

The enthalpies of solution, (Delta(s)H degrees), of cobalt(II) trifluo romethanesulfonate, sodium trifluoromethanesulfonate and sodium perchl orate have been measured in acetonitrile (AN)-methanol (MeOH) mixtures over the whole range of solvent composition. From these data the enth alpies of transfer, (Delta d(t)H degrees) for cobalt(II), CF3SO3- and ClO4- ions have been determined using the literature data for sodium i on. The visible absorption spectra of Co(CF3SO3)(2)-acetonitrile-metha nol solutions, sensitive to the changes in the first solvation sphere of cobalt(II) ion, have been used as an aid in the interpretation of t he calorimetric data. The solvation of the ions examined has been disc ussed in terms of ion-solvent and solvent-solvent interactions in acet onitrile-methanol mixtures and compared with the results in acetonitri le-water mixtures.