Raman and infrared study on the effects of dimethylsulphoxide (DMSO) on water structure

Abstract

Abstract Raman and infrared spectra of liquid dimethylsulphoxide (DMSO) and DMSO‐water mixtures in a wide range of concentrations are reported and discussed. It is found that changes in the vibrational spectra can be related to a gradual insertion of water molecules in the cluster structure of liquid DMSO. In the more dilute aqueous solutions a gradual lowering of the ν s =0 stretching frequency is observed and this can be related to the cooperative character of DMSO–water interactions. The interpretation of the spectra is in agreement with the capacity of DMSO for ‘breaking’ the structure of water in the more concentrated aqueous solutions and ‘enhancing’ it in very dilute solutions.