Synthesis And Liquid Crystal Properties Of Triazole Easter

Liquid crystal materials are more and more widely used in life,and have been used in liquid crystal display,nano materials,anti electromagnetic and medical composite materials.Ester liquid crystal compounds have been widely studied because of their wide mesomorphic temperature range,small thermal deformation and good optical properties.The [1,2,3] triazole heterocycles can increase the phase stability of liquid crystal compounds and enrich the phase types of liquid crystal compounds.In this paper,triazole ring was introduced into ester liquid crystal compounds to construct polycyclic liquid crystal compounds,which were modified by side chains of different lengths.The liquid crystalline properties were studied by hot stage polarizing microscope(POM)and differential scanning calorimetry(DSC),so as to seek liquid crystal materials with good properties and practical value.In this paper,ester compounds were prepared by esterification of hydroquinone and trans-1,4-cyclohexanediol with 4-ethynylbenzoic acid,and then a series of triazole esters with different length side chain were synthesized by click reaction with azides.The structures of the synthesized compounds were characterized by IR,HRMS and NMR.The optical properties of the compounds were studied by UV and fluorescence spectra.The liquid crystal properties were investigated by DSC and POM.The results show that the compounds with chain length of 12 or 14 carbon have liquid crystalline property.Moreover,the stability of the triazole ester liquid crystal compounds with the rigid structure of hydroquinone as the central core is higher than that of the triazole ester with the flexible trans-1,4-cyclohexanediol as the central core;the introduction of ferrocene at the end does not induce the liquid crystalline of the compounds.