Raman spectral studies of aqueous solutions of non-electrolytes: Dimethylsulfoxide, acetone and acetonitrile

Abstract

Raman spectra of aqueous solutions of dimethylsulfoxide, dimethylsulfoxide-d₆, acetone and acetonitrile are reported in the OH stretching region, and in the stretching regions of the functional groups of these solutes. Raman intensities and frequency shifts of these bands show definite trends with varying concentrations of the solutions. The results obtained are discussed in terms of the mixture model of water, and they are compared with results obtained from Raman spectral studies of aqueous electrolytes. It is proposed that water structure breaking and the formation of solute-solvent complexes when organic solutes are added to water can account for these results.