Solvent polarity effects on the E/Z conformational equilibrium of N-1- naphthylamides

Article abstract of DOI:10.1016/S0040-4020(98)00379-2

The ratio of the E and Z conformers of N-alkyl-N-l-naphthylformamides has been measured in a series of solvents using NMR spectroscopy. A linear relationship was found between the free energy of the conformational equilibrium, ΔG⁰, and the relative dielectric permittivity of the solvent. The comparison of NMR data with quantum-chemically calculated SCRF heats of equilibria reveals that the solvent effect is a combination of both the electrostatic and specific solute-solvent interactions, the latter being directly connected to the solvent-induced sterical deformations of the solute molecule.