Solvation studies of copper(I) perchlorate and bis(2,9-dimethyl-1,10-phenanthroline) copper(I) perchlorate in acetonitrile + trimethylphosphate mixtures at 298K

Abstract

Molar conductances of tetrabutylammonium tetraphenylborate (Bu₄NClO₄), tetrabutylammonium perchlorate (Bu₄NClO₄), copper(l) perchlorate (CuCIO₄) and bis (2,9-dimethyl-1, 10-phenanthroline) copper(l) perchlorate [Cu(DMPhen)₂CIO₄ ] have been measured in acetonitrile + trimethylphosphate (AN + TMPA) mixtures at 298K. Limiting molar conductances Ù_o for various electrolytes have been calculated using Shedlovsky's method and split into the contribution of individual ions by the Bu₄NBPh₄ assumption. Solvated radii (r_i) for Cu⁺, CIO₄^- and [Cu(DMPhen)₂]⁺ have been calculated. The solvated radius for Cu⁺ remains almost constant up to »35 mol % TMPA and then increases significantly with further increase in mol % TMPA. The result shows preferential solvation of Cu⁺ by AN up to »35 mol % TMPA. At higher mol % TMPA, some AN molecules from the solvation sphere of Cu⁺ are replaced by bulkier TMPA molecules. For CIO₄^- the ri value decreases throughout with the increase in TMPA concentration. This result shows better solvation of CIO₄^- by AN which decreases with the increase in TMPA mol %. The ri value for [Cu(DMPhen)₂]⁺ remains constant at all the AN + TMPA compositions showing either no solvation or the solvation by AN or TMPA to the same extent.