1973 Volume 46 Issue 9 Pages 2716-2721
In order to examine the effect of solvents on the hyperfine splittings of anion radical the electron spin resonance spectra of substituted nitrobenzene anion radicals were studied. The effect of hydroxylic solvent is enhanced when the nitro group is forced out of the plane of the benzene ring due to the steric influence of the bulky functional group at the ortho position. The effect is reduced when the nitro group forms intramolecular hydrogen bond with the hydroxyl group at the ortho position. A model for the solvent effect considering the hindered rotation of the nitro group in the radical molecule caused by the formation of intermolecular hydrogen bond with solvent is found to be reasonable from a molecular orbital calculation, taking account of changes in molecular orbital parameters resulting from hydroxylic solvation. The shifts in polarographic half wave potentials with the solvent system as well as the dehalogenation reaction in the course of electrochemical reduction of halonitrobenzenes is interpreted by means of the model.
This article cannot obtain the latest cited-by information.