Mechanism of Geometrical Isomerization about the Carbon- Nitrogen Double Bond

Article abstract of DOI:10.1021/jo00263a022

For pyrazolone azomethines and N-benzylideneanilines, we report kinetic effects of pressure, solvent, and substituent on geometrical isomerization about the carbon-nitrogen double bond.Our results demonstrate the versatility of the inversion mechanism in these two groups of compounds.Invalidated is the rotation mechanism that had been previously predicted for pyrazolone azomethines with electron-donating substituents in the para position of the aromatic ring attached to the imino nitrogen.Contrary to azobenzene, mere push-pull substitution in N- benzylideneanilines is not enough to realize the rotation mechanism even in a relatively polar solvent such as methanol.