The N,N '-bis[4-(4-n-alkyloxybenzoyloxy)benzylidene]phenylene-1,3-diamines: mesophase behaviour and physical properties

A homologous series of banana-shaped compounds (n=1-12) is described. The s hort-chain derivatives exhibit a B-6 phase, while B-6/B-1 dimorphism is fou nd for the pentyloxy and hexyloxy homologues. The B-1 phase of the compound s having longer alkyloxy chains is changed to a B-2 phase for the compounds with n=11 and 12. The phase characterization was performed using their opt ical textures and by means of X-ray investigations. Transition enthalpics w ere measured using DSC. In addition, density measurements were performed on one selected homologue. The compound n=8 exhibiting a B-1 phase was invest igated also by high-pressure DTA.