Conformational change of N-benzylideneanilines in crystals

The crystal structures of N-(4-nitrobenzylidene)aniline (1), N-(4-chlorobenzylidene)-4-methylaniline (2) and N-(4-methylbenzylidene)-4-methylaniline (3) were determined by X-ray diffraction analyses at various temperatures. A dynamic disorder was observed in the crystal structures of all compounds. The dynamic disorder is accounted for in terms of a conformational change involving a pedal motion in the crystals.