New liquid crystalline conjugated derivatives of 3,3 '-bipyridine as components for optoelectronic materials

We present a series of new 6,6'-distyryl-3,3'-bipyridine derivatives synthe sized via a Knoevenagel condensation reaction and disubstituted with electr on donor and acceptor groups. These molecules were characterized by spectro scopic methods (NMR, Raman, UV-vis, photoluminescence). These compounds wer e all found to exhibit thermotropic liquid crystalline (LC) phases, the str uctures of which were analyzed by DSC and temperature-dependent X-ray diffr action. The high degree of conjugation and the mesogenic character of these molecules could lead to nonlinear optical (NLO) applications for the "push -pull" compounds. Absorption in the UV range and blue fluorescence are othe r characteristics of some members of this group. The latter property opens up applications as light-emitting diodes (LEDs).