Solvent effects in proton nuclear magnetic resonance spectra of substituted benzenes

Physics Institute, University of Basel, Switzerland.

Abstract

The influence of solvents with high dielectric constants on the nuclear magnetic resonance spectra of substituted benzenes is interpreted in terms of an electrostatic reaction field.

Benzene solvent effects are attributed to a non-random distribution of benzene solvent molecules in the neighbourhood of the solute molecules. These effects can be shown to be proportional to the solute substituent electric dipole moments. On the other hand evidence is given against a simple one-to-one complex formation responsible for the solvent effects observed.

Steric contributions to solvent effects of benzene that have been measured in substituted mesitylenes and durenes are discussed.