Molecular Design, Synthesis And Mesomorphism Of Truxene Discotic Liquid

Discotic liquid crystals self-assemble to highly ordered hexagonal columnar mesophase (Colho), exhibit anisotropic high charge carrier mobility and show huge potential application as organic electronic materials. In this paper, we synthesize some very key intermediate compounds and further synthesize an series of turxene Discotic liquid crystals, which property were studied. The structure characterization of these compounds were carried out with 1H NMR, 13C NMR and EA. Thermal gravimetry analysis (TGA) showed these compounds have good thermal stability. The thermotropic liquid crystal properties were studied through polarizing optical microscopy (POM) , differential scanning calorimetry (DSC) and XRD. The structure-property relationship of these molecules was proposed, and it is hopefully to contribute to the molecular designing and practical application of truxene liquid crystals as new materials.The thesis consists of four chapters:1. Chapter one briefly introduced the fundamental knowledge about liquid crystal materials and the researching and developing of truxene2. We have developed an efficient method for the synthesis of C3-symmetrical truxene derivative 2,7,12-trihydroxy-3,8,13-trimethoxytruxene, and further a serious of ether-ester mixed tail truxene discogen HTn. The truxene discogen HTn have been characterized by using 1H and 13C NMR and high resolution Mass. The liquid crystal properties have been investigated by using POM, DSC and XRD. It exhibits an ordered hexagonal column mesophase (Colho) in a fairly wide temperature range.3. In the synthesize process of 2,7,12-tridecyloxy -3,8,13-trimethoxytruxene, we found one equivalent Monomer, One-third of equivalent p-toluenesulfonic acid monohydrate and One-sixth equivalent ethane-1,2-diol was refluxed in toluene(10 mL) to get a good yield and further demethylated yielding the key intermediate 2,7,12-tridecyloxy-3,8,13-trihydroxytruxene. Both of them show an ordered hexagonal column mesophase (Colho) in the POM and DSC and only have three tails.