非手性β-甲基丁基多联苯异硫氰酸酯液晶合成及高频介电性能  

Synthesis of liquid crystals of non-chiral β-methylbutyl polybiphenyl isothiocyanate and high-frequency dielectric properties

作　　者：涂友兰 张磊 雷孟龙 吴胜莉 刘豪浩 张智勇 陈红梅 汪相如 TU Youlan;ZHANG Lei;LEI Menglong;WU Shengli;LIU Haohao;ZHANG Zhiyong;CHEN Hongmei;WANG Xiangru(Department of Chemistry and Environmental Engineering,Wuhan Polytechnic University,Wuhan 430023,China;School of Electronic Science and Engineering,University of Electronic Science and Technology,Chengdu 611730,China)

机构地区：[1]武汉轻工大学化学与环境工程学院,湖北武汉430023 [2]电子科技大学光电科学与工程学院,四川成都611730

出　　处：《液晶与显示》2024年第12期1735-1743,共9页Chinese Journal of Liquid Crystals and Displays

基　　金：国家装发部预研基金项目(No.61409230701);广东省重点领域研发项目(No.2019B010158001)。

摘　　要：本文以非手性DL-(±)-2-甲基-1-丁醇和溴苯为原料,通过Appel反应、Grignard偶联反应、Suzuki偶联反应等多种合成方法,设计合成了6种新型异硫氰基非手性β-甲基丁基多联苯类液晶化合物A1~A6,并对其分子结构、相态及微波介电性能进行测试分析。结果表明,三联苯化合物A1~A3的熔点随氟原子数量增多而逐渐降低;其中A3熔点最低,只有37℃,向列相温宽达71℃;当氟原子数量和取代位置相同时,β-甲基丁基化合物的熔点低于正丁基化合物。当四联苯侧位取代基改变时,—F取代化合物A4的熔点最低,其次是—CH_(3)取代化合物A6,而—Cl取代化合物A5的熔点最高,三者的向列相温度范围均大于120℃。在波频9~30 GHz时,化合物A2~A6的介电性能较好,介电各向异性均大于0.903,最大介电损耗在0.003 3~0.010 7之间,其中化合物A6在19 GHz时的最大介电损耗为0.003 8,品质因数高达66.12。不同取代基对降低最大(垂直)介电损耗的贡献程度不同:—CH_(3)>—Cl>—F;不同取代基对提高介电各向异性(Δε_(r))的贡献为:—F>—Cl>—CH_(3)。Six new isothiocyanato-non-chiralβ-methylbutyl polybiphenyl liquid crystal compounds A1~A6 are designed and synthesized by various synthetic methods,such as Appel reaction,Grignard reaction,Suzuki coupling reaction,etc.,using achiral DL-(±)-2-methyl-1-butanol and bromobenzene as raw materials,and the molecular structures,phases,and microwave dielectric properties of these compounds have been tested and analyzed.The results show that the melting points of the triphenyl liquid crystal compounds A1~A3 gradually decrease with the increase of the number of fluorine atoms,and the lowest melting point reaches 37℃,and the width of its nematic phase temperature reaches 71℃.When the substituents of fluorine atoms are in the same position and the same number,the melting point of the compounds withβ-methylbutyl is lower than that of the compounds with n-butyl group.However,when the substituents of the tetrabiphenyl benzene ring side position are changed,the melting point of the—F-substituted compounds A4 is the lowest,followed by that of the—CH_(3) substituent A6,and—Cl substituent A5 has the highest melting point,and all three of them have a nematic phase temperature range of more than 120℃.In the microwave band 9~30 GHz,compounds A2~A6 show good dielectric properties with dielectric anisotropy greater than 0.903 and vertical dielectric loss values between 0.0033~0.0107,among which the vertical dielectric loss of compound A6 is as low as 0.0038 with a quality factor of 66.12 at 19 GHz.The different substituents contribute differently to the reduction of the maximum(vertical)dielectric loss:—CH_(3)>—Cl>—F,and the magnitude of different substituents to the improvement of the dielectric anisotropy(Δε_(r))value is—F>—Cl>—CH_(3).

关 键 词：微波用液晶 介电损耗 β-甲基丁基多联苯 氟取代 合成 

分 类 号：O753.2[理学—晶体学]