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

Abstract

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 SB-Cl exhibits the lowest clearing transition temperature of 180 o C and the widest SmCP phase range of 129 o 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.

Chemical Structures, Mesogenic Properties, and Synthesis of Liquid Crystals with Bent‐Core Structures

“…This moiety has been widely used in rod-like liquid crystals and is well known to stabilize the imine group, thus improving its stability to heat and moisture. In the case of bent-core liquid crystals, the presence of this substituent promotes a strong stabilization of the mesomorphism in comparison of the non-substituted analog, both in 1,3phenylene [6d,65] and 3,4´-biphenylene [66] derivatives. In contrast, Pintre et al [5d] explored the effect of the hydroxyl group in the inner and outer rings of all-ester connected 3,4´-biphenyl-based bentcore structures.…”