Synthesis And Properties Of Novel Liquid Crystals Based On [1,2,3]-Triazole And Dichroic Dyes

The introduction of heteroatoms into liquid crystals can result in large changes in the corresponding liquid-crystalline phases and/or in the physical properties of the observed phases, such as enrich the range of different liquid crystalline phases, change the molecular dipole and dielectric anisotropy. Low threshold voltage and fast response time are required in LC-related devices.In this work, a series of novel liquid crystals containing [1,2,3]-triazole ring were synthesized via click chemistry. Their mesomorphic properties and photoelectric properties were investigated and the results indicated that most of compounds exhibited SmA over a wide temperature range (153.3-201.0℃). Mixed compound T4 with LC 50100, threshold voltage and response time of the mixture were shorten by 0.124 V and 77.9 ms, respectively.10 compounds based on fluorenone were designed and synthesized and their properties were discussed. The compounds containing ester linkage were easy to form mesophase with a wide temperature range. The widest temperature range of compound TOF1 was up to 139.7℃. In addition, the compounds in this series showed bright colours. Mixed compound MOF2 with LC 50100, the threshold voltage of the mixture was lowered by 0.207 V and response time was reduced by 28.1 ms.GH-LCDs have many merits, such as displaying information in excellent colour, wide viewing angle, high brightness and good contrast ratio. Owing to the combination of the excellent hues and high brightness levels of emissive displays with the desirable features of LCDs, fluorescent dyes based on GH-LCDs have been proposed as a less energy consuming display for portable electronics. Therefore, it's necessary to develop novel dichroic fluorescent dyes with good performance.A new series of dyes containing N-substituted-1,8-naphthalimides (Y) have been designed and synthesized. Spectroscopic tests showed that these dyes emitted strong bule and yellow-green fluorescence at 419-504 nm with high quantum yields (0.7). When dispered in LC 80B and MLC 6237-01ε, these dyes showed negative fluorescent dichroism and SA, SF were up to-0.38,-0.26, respectively.In order to broaden the color range, dyes based on the 3-substitutedacenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile have been designed and synthesized. Spectroscopic tests indicated that these dyes emitted yellow, orange-yellow and orange-red fluorescence at 506-588 nm, except compound B3. These dyes showed negative fluorescent dichroism in LC 80B and MLC 6237-01ε. And SA, SF were up to -0.32,-0.28, respectively.