Ionic liquid crystals bearing bipyridinium and pentaphenylene groups

Molecular and polymeric liquid crystals bearing bipyridinium and pentaphenylene groups were synthesized and characterized. These new ionic liquid crystals develop single layer smectic-type mesophases with molecules tilted or orthogonal with respect to the smectic planes as a function of temperature. A high tendency to develop a homeotropic behavior was observed for the molecular liquid crystals. A molecular arrangement was proposed in which the different parts of molecules are fully segregated from one another with the ionic groups stabilizing the smectic order. These molecules show a luminescence in the blue region that combined with the liquid-crystalline behavior could be interesting for the fabrication of light emitting thin films with ordered molecular emitters.