Synthesis, Characterization and Mesomorphic Properties of <i>N,N'-(</i>1,4-Phenylene(methanylylidene))bis(4-(hexyloxy)aniline)

Abstract

Liquid crystals (LCs) are compounds that have properties between isotropic liquids and solid crystal materials. Although there is not a parameter to predict this behavior, the liquid crystals reported until now have common characteristics, for example rigid groups such as columns or rods within its structures, and long hydrocarbon chains that give flexibility. In this work we report the synthesis and characterization of LCN,N'-(1,4-phenylene bis (methanylylidene)) bis (4-(hexyloxy) aniline). The compound was characterized by infrared (IR), raman and1H-nuclear magnetic resonance (1H-NMR) spectroscopies. The mesomorphic properties were determined by Differential Scanning Calorimetry (DSC) and Polarized Optical Microscopy (POM). The compoundN,N'-(1,4-phenylene bis (methanylylidene)) bis (4-(hexyloxy) aniline) was obtained with a yield of 87 % and purity of 99.9 % determined by elementary analysis. The POM study revealed that this compound have a typical low molecular weight liquid crystal behavior. At temperatures of 157 and 174 °C typical mesophases of liquid crystals were observed; the phase transitions were analyzed by DSC. The POM images reveal the typical birefringence of liquid crystal behavior and different anisotropic textures of smectic and nematic mesophases, these textures are characteristic of the benzylideneanilines or Schiff bases.