| abstract |
Heterocyclic derivatives of 1,2-difluorobenzene of the formula I. wherein R¹ and R² are each independently an alkyl group with 1-15 C atoms, in which one or more CH₂ groups are selected by a bivalent radical selected from the group consisting of -O-, -S-, -CO-, -O-CO -, -CO-O-, -CH = CH- and -C≡C- can be replaced, two heteroatoms not being directly linked to one another, A¹ and A² each independently represent an unsubstituted or fluorine-substituted or polysubstituted 1,4-phenylene group, in which one or two CH groups can also be replaced by N, a 1,3,4-thiadiazole-2,5-diyl Group or a trans-1,4-cyclohexylene group, m and n each represent 0 or 2, 0 0 or 1, and p means 0, 1 or 2, where (o + p) is 1, 2 or 3 and in the case p = 2 the groups A² and n can be the same or different, with the proviso that at least one of the groups A¹ and A² is a 1,3,4-thiadiazole 2,5-diyl group or an unsubstituted or substituted 1,4-phenylene group in which one or two CH groups are replaced by N are suitable as components of liquid-crystalline phases. |