Trans-2-phenyl-5-trans-4'-alkylcyclohexyl-1,3-dioxane derivatives represented by the general formula: ##STR1## wherein R is a linear alkyl group of 1 to 10 carbon atoms, A is a single covalent bond or a --CH.sub.2 CH.sub.2 -- group, X is F or CN, Y is F if X is CN or Y is H or F if X is F, and the cyclohexane ring and the 1,3-dioxane ring are trans isomers. The 1,3-dioxane derivatives have large positive dielectric constant anisotropy (.DELTA..epsilon.), small birefringence (.DELTA.n) and have good compatibility with other liquid crystal compounds. The dioxane derivatives may be included in liquid crystal compositions for improved display devices having a low threshold voltage, a low driving voltage and a wide visual angle.
以一般式表示的直链烷基为1至10个
碳原子的烷基
环己烷衍
生物为:##
STR1## 其中R是1至10个
碳原子的线性烷基,A是一个单共价键或一个--CH.sub.2 CH.sub.2--基团,X为F或CN,如果X为CN,则Y为F,如果X为F,则Y为H或F,
环己烷环和1,3-二
氧杂
环丙烷环为反式异构体。1,3-二
氧杂
环丙烷衍
生物具有较大的正介电常数各向异性(Δε),较小的双折射(Δn),并且与其他
液晶化合物具有良好的相容性。这些二
氧杂
环丙烷衍
生物可以包含在
液晶组合物中,用于改善具有低阈值电压、低驱动电压和宽视角的显示装置。