| abstract |
New compounds of the general formula I:n wherein R¹ is a normal or branched alkyl chain H 2n+1 C n - or a normal or branched alkoxy group H 2n+1 C n O-, n being an integer number from 1 to 12; X is a bridging group from the set: -COO-, -OCO-, -CH₂O-, -OCH₂-, -COCH₂-, -CHOHCH₂-, -CH=CH-,-CH₂CH₂-, -CHClCH₂-, -CHCNCH₂-, -CHBrCH₂-, -CHFCH₂-, -CHOCH₃CH₂-; Y is a terminal group from the set: -NO₂, -NH₂, -NCS, -Cl, -Br, -F; the cyclohexane rings are trans-1,4-disubstituted ones and the benzene rings are 1,4-disubstituted ones, and besides one of them may contain sometimes additionally a fluorine atom in position 2 or 3, k and l are integer numbers from the set: 0, 1, 2 fulfilling the condition that k+1=2 or 3; besides, if X denotes the -COO- or -OCO- group, then k+1 also may assume the value of 1 , their manufacture and liquid crystalline admixture containing them and use for electro-optical devices as dielectrics are described. |