THE INFLUENCE OF THE SOLVENT ON THE CONFORMATIONAL ENERGY DIFFERENCES DUE TO THE ANOMERIC EFFECT

The solvation free energy DELTA-G(sol) of molecules exhibiting the anomeric effect is computed in an approach that considers a continuous distribution for the solvent. A partition of DELTA-G(sol) into separately evaluated contributions confirms that changes in the energy of the systems due to changes in conformation of the solute are ruled by the electrostatic contribution. A comparison with the "exact" values indicates that the approximate expression for the electrostatic contribution to DELTA-G(sol) are not accurate enough to permit a proper modeling of the solvent influence on the anomeric effect. The systems are composed of methanediol, methoxymethanol, dimethoxymethane, and 2-methoxytetrahydropyran in carbon tetrachloride, chloroform, acetone, and water. The calculations have been performed at the SCF level with the STO-3G and 4-31G basis sets.