Synthesis and Properties of New Thiadiazole Liquid Crystalline Compounds with Amide Central Linkages

Sixteen 2,5-bisphenyl-1,3,4-thiadiazoles with amide central linkages were synthesized. Their chemical structures were analyzed by IR and 1H NMR spectrometry. The liquid crystalline properties were determined by POM and DSC. The results show that they are all thermally stability liquid crystals and have higher phase transition temperatures and wide phase transition temperature ranges. The paper indicated that the amide central linkages are more conductive to smectic phase. The effect of the carbon atom number of terminal group on mesomorphic properties was discussed.