液晶与显示2017，Vol.32Issue(9)：692-700,9.DOI:10.3788/YJYXS20173209.0692
乙炔桥键四环异硫氰酸酯液晶化合物的合成及性能
Synthesis and properties of four-ring isothiocyanate liquid crystals with ethynyl bridge
摘要
Abstract
In order to investigate the relationship between the structures and properties of LCs,twelve isothiocyanate liquid crystals composed of four-ring core and ethynyl bridge were synthesized via six steps based on arylboronic acid and 1-bromo-2-fluoro-4-iodobenzene.Their structures were confirmed by infrared spectrometry (IR)and 1 H-nuclear magnetic resonance (1 H NMR).The mesomorphic properties,birefringence and dielectric anisotropy of these compounds were investigated.The result reveals that all these compounds exhibit high clearing points (>300 ℃),wide nematic phase range (>150 ℃),high birefringence (Δn =0.40~0.51)and large dielectric anisotropy (Δε>17).The melt-ing points of these compounds decreased with increasing the carbon number of alkyl chain,while the smectic phase intervals enlarged.Lateral fluorines in the position of Y,Z result in a drop of the melt-ing points and the clearing points,but an additional fluorine in the position of X results in an increase of the melting points and decrease of the clearing points.Replacement of the left benzene ring by cy-clohexane is useful to lower the melting point and increase nematic phase range.The introduction of lateral fluorine will reduce the birefringence of 0.008~0.036.The target compounds are useful for ele-vating the birefringence values,clearing points and reduce the threshold voltage of liquid crystal mix-tures.关键词
液晶/乙炔/异硫氰酸酯/介晶性/双折射率Key words
liquid crystals/ethynyl/isothiocyanate/nematic phase/birefringence引用本文复制引用
李娟利,彭增辉,李建,安忠维,张璐..乙炔桥键四环异硫氰酸酯液晶化合物的合成及性能[J].液晶与显示,2017,32(9):692-700,9.基金项目
国防基础科研项目(No.B0520132007,No.B1120132028) （No.B0520132007,No.B1120132028）
陕西省科技攻关项目(No.2016GY-212) （No.2016GY-212）
应用光学国家重点实验室开放基金(No.Y6133FQ112) （No.Y6133FQ112）
国家自然科学基金(No.61378075) Supported by the Defense Industrial Technology Development Program of China(No.B0520132007,No. B1120132028) （No.61378075）
the Key Science and Technology Program of Shaanxi Province,China(No.2016GY-212) （No.2016GY-212）
the State Key Laboratory of Applied Optics(No.Y6133FQ112) （No.Y6133FQ112）
the National Natural Science Foundation of China(No.61378075) （No.61378075）
