Computational studies in aqueous and chloroform solutions of complex organic solutes: distinctive effects of the solvent on solutes with small chemical differences

The solvation in chloroform and aqueous solutions of three complex organic molecules have been investigated using self-consistent reaction-field (SCRF ) methods. Solutes contain a phenyl ring with two attached methoxy groups, differing only in the chemical nature of the two functional groups located at the end of a flexible aliphatic chain. The study of solutes with only su ch small difference constitute a challenge for SCRF methods. Calculations i n solution were performed on a selected number of conformers generated thro ugh a conformational search. The results provide a picture of the changes i nduced by the different solvents on the conformational preferences of the s olutes. Conformations are described using general structural patterns rathe r than discrete structures due to the flexibility of the methoxy groups and the aliphatic chain. On the other hand, solute-solvent interactions have b een analyzed and related with the transfer free energies and the partition coefficients to chloroform from water. (C) 1999 Elsevier Science B.V. All r ights reserved.