| abstract |
Disclosed are liquid crystal compounds of formula IR1-P-X-(A1-Z1)n-A2-R2Iwherein R is <IMAGE> HWN, or HSCH2(CH2)mCOO, W is H, Cl or C1-5-alkyl, and m is 1-7, P is C1-12 alkylene, one or more CH2 groups optionally being replaced by O, X is -O-, -S-, -COO-, -OCO- or a single bond, R2 is C1-15-alkyl optionally substituted by halogen, one or more CH2 groups optionally replaced by -O-, -S-, -CO-, -O-CO-, -CO-O- or -O-CO-O-; R1-P-X, CN, F, Cl or -V-Q-T, V is -O-, -S- or a single bond, Q is -CH2-, -CHF-, -CF2-, T is F or Cl, n is 1 or 2, A1, A2 are 1,4-phenylene optionally substituted by F, Cl, CN or -W-CrHsF2r+1-s, or one of A1 or A2 is <IMAGE> pyrimidine-2,5-diyl or pyrimidine-2,5 diyl, Z1 is -CO-O-, -O-CO-, -CH2CH2- or a single bond, r is 1 or 2, s is O, 1, 2, 3, 4, or 5, W is a single bond, -O-, -S- or -CO-, with the provisos (i) that at least one of A1 and A2 is a 1,4-phenylene group which is mono-or polysubstituted by Cl, CN or -W-CrHsF2r+1-s, said substituted 1,4-phenylene group optionally additionally substituted by one or more F-atoms, and (ii) that in case n=2 (a) only one of Z1 is -COO- or -OCO- or (b) at least one of A1 and A2 is double substituted or (c) at least two of A1 and A2 are substituted. |