Evidence of an inversion mechanism for the thermal cis–trans isomerization of push–pull azobenzenes. A volumetric study
Abstract
The partial molar volumes of trans-4-dimethylamino-4′-nitroazobenzene in solvents of different polarities are linearly related to the activation volumes in the same solvents for the thermal cis-trans isomerization of this species, which affords unequivocal evidence for an inversion transition state.