THEORETICAL INVESTIGATION OF THE ELECTRONIC-PROPERTIES OF DONOR-ACCEPTOR N-BENZYLIDENEANILINES AND RELATED MOLECULES

The dipole moments, transition energies and hyperpolarizabilities of a substituted stilbene, azobenzene and two isomeric-benzylideneanilines containing the 4-dimethylamino-group at one end of the molecule and t he 4-nitro-group at the other, have been calculated using a semi-empir ical sum-over-states method on structures optimized with the 3-21G bas is set. An excellent correlation is found between the calculated and e xperimental spectra. The azobenzene is predicted to have the largest h yperpolarizability of this series of molecules, followed by the stilbe ne and N-(nitrobenzylidene)aniline which have comparable values, with the non-planar N-(benzylidene)nitroaniline showing the smallest value.