| abstract |
Compounds with the general formula (I): R-S1-A-Z1-B-S2-R, where A and B are independent ring systems with the formulae (a1), (a2) or (b),whereby in the trans-1,4-cyclohexylene ring, one or two non-adjacent CH2 groups may be replaced by oxygen, and whereby, in the 1,4-phenylene ring, one or two non-adjacent CH groups may be replaced by nitrogen; L1, L2, L3 represent, independently, hydrogen, C1-C20-alkyl, C1-C20-alkenyl, C1-C20-alkyloxy, C1-C20-alkyloxy carbonyl, formyl, C1C20-alkyl carbonyl, C1-C20-alkyl carbonyloxy, halogen, cyano or nitro; Z1, Z2, Z3 represent, independently, a single bond, -CH2CH2-, -CH2O-, -OCH2-, -COO-, -OOC-, -(CH2)4-, -O(CH2)3-, -(CH2)3O- or -C=C-; S1, S2 represent a spacer unit; R represents crosslinkable groups, with the proviso that at least one of the ring systems A or B represents a ring system with the formula (a1) or (a2), Z1 or Z2 denoting a single bond. |