Conformations and dipole moments of furan derivatives in solution

Abstract

Dielectric measurements have been made on solutions of tetrahydrofuran in water and of tetra-hydrofurfuryl alcohol in carbon tetrachloride, cyclohexane and water. Buckingham's theory has been used to calculate apparent dipole moments of the solutes, and the dipole moment of tetrahydrofurfuryl alcohol has also been estimated using bound moments and semi-empirical potential energy functions. The calculated and experimental results for non-polar solvents agree, but the apparent dipole moment in aqueous solution is higher than that calculated for any likely conformation. Using a clathrate model for an aqueous solution of tetrahydrofuran the effect of the reaction field due to near neighbour water molecules on the interstitial solute molecule has been estimated, but the model cannot account for the high experimental apparent dipole moment.