Cyclohexane derivatives, liquid crystal compositions comprising the same and liquid crystal display devices

摘要

Liquid crystalline compounds are disclosed which have large dielectric anisotropy and relatively low viscosity, and which are represented by formula (1) wherein R<1> represents hydrogen or C1-C15 alkyl in which one or more non-adjacent methylene may be replaced by oxygen, sulfur or -CH=CH- and one or more hydrogen may be replaced by halogen; R<2> represents hydrogen, cyano, halogen or C1-C15 alkyl in which one or more non-adjacent methylene may be replaced by oxygen, sulfur or -CH=CH- and one or more hydrogen may be replaced by halogen; L represents halogen or hydrogen; A<1>, A<2>, A<4> and A<5> each independently represent trans-1,4-cyclohexylene or 1,4-phenylene, one or more -CH2- in the trans-1,4-cyclohexylene may be replaced by oxygen or sulfur, one or more =CH- in the 1,4-phenylene may be replaced by nitrogen, and one or more hydrogen in the 1,4-phenylene ring may be replaced by halogen; A<3> represents trans-1,4-cyclohexylene in which one or more -CH2- may be replaced by oxygen or sulfur; Z<1>,Z<2>,Z<3> and Z<4> each independently represent -COO-, -OCO-, -CH2CH2-, -(CH2)4-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or a single bond; Q represents -CF2CH2- or -CH2CF2-; and k, l, m and n each independently represent 0 or 1 with the condition of k+l+m+n