Synthesis and Characterization of Achiral Bent-Core Liquid Crystalline Molecules Containing Salicylaldimine-Based with a Wide Temperature Range of SmCP Phase

The design and synthesis of a series bent-core materials base on a 3,4'-biphenyldiol central core containing salicylaldimine-based and two terminal tetradecyloxy tails are reported. In addition, the effects of lateral substituents (R = F and Cl) at the biphenyl core into 3'-position are examined. These substituents have a strong influence in reducing the clearing temperatures and increasing temperature range of SmCP phase. Upon cooling process the isotropic liquid, compound SR-CI exhibits the lowest clearing transition temperature of 180 degrees C and the widest SmCP phase range of 129 degrees C. The mesophase behaviour were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and electro-optical (EO) measurements in the mesophase temperature range.