Correlations and statistical analysis of solvent molecule hydrogen bonding – a case study of dimethyl sulfoxide (DMSO)

Abstract

A correlation and statistical study has been performed on crystal structures reported in the Cambridge Structural Database (CSD) that contain solvated dimethylsulfoxide (DMSO) molecules, with an aim to explore the existence of a plausible relationship between the variability of predicted aqueous solubility values and the intermolecular hydrogen bonds present between the solvent and the host molecule. Contour plots were used to demonstrate how the electronegativity of a hydrogen donor highly affected the distribution of hydrogen bonds around the DMSO solvent molecule. The existence of an inverse relationship between the distance and angle of an interaction was established, as was the influence of the total number of hydrogen bonds within a solvent molecule on such properties. It was confirmed that generally, the individual strength of a contact decreased with an increase in the amount of interactions with the same hydrogen bond acceptor. A negative association was detected between the theoretical aqueous solubility values and both the number of coordinates as well as the number of contacts. A regression model was fitted using the logarithmic transformation of the predicted solubility values as the dependent variable. The model retained the following predicators: the number of coordinates, the dimensions of the intermolecular hydrogen bonds, the classification of contacts according to the environment of their respective solvent molecules and the number of interactions within the asymmetric unit. These characteristics were discovered to be statistically significant factors which affected the extent of aqueous solubility of DMSO solvates to different degrees.