Weak Complexes of Sulfur and Selenium Oxo Species A Thermodynamic View on Solvent Effects in Mixed Solvents PDF

Keywords

solvents, thermodynamic, infrared

Abstract

Free energies and enthalpies of formation of the weak complexes SO2X-, SOCl2X-, SOBr2X- and SO2Cl2X- (X= Cl, Br, I) in the mixed solvent acetonitrile-dimethyl sulphoxide (MeCN-dmso) can be described by the existence of solute-solvent and solvent-solvent interactions. Stability constants of dmso or MeCN with the sulphur compounds SO2, SOCl2, SOBr2 and SO2Cl2 are evidence to solute-solvent interactions. Solvent-solvent interactions are confirmed from H(vap), S(vap) and H(vis) of the mixtures of MeCN and dmso. They are supplemented by the excess functions from refractive index, dielectric constants and densities of solvent mixtures. Infrared and Raman shifts point to the formation of 1:1 MeCN-dmso adducts.