| abstract |
Trifluorobenzene derivatives having good stability and a large positive dielectric anisotropy value and which may be used in liquid crystal compositions, have the formula: <CHEM> wherein R represents an alkyl group of 1 to 10 carbon atoms in which one -CH2- group or two non-adjacent -CH2- groups may be replaced by an oxygen atom and/or a -CO- group and/or a -COO- group and/or a -CH=CH- group; -A- and -B- each represent a 1,4-cyclohexylene, 1,4-phenylene, pyrimidine-2,5-diyl or 1,3-dioxane-2,5-diyl group; 1 represents 0, 1 or 2; m represents 0, 1 or 2 and 1+m>/=1; and Z<1> and Z<2> are the same or different and each represents a group -COO-, -CH2CH2-, -OCH2-, -CH2- or -CH=CH-, or a single bond. |