| abstract |
Vinylene compounds of the formula I R<1>-Q<1>-(CH2)m-CH=CH-(CH2)n-Q<2>-(Z-Q<3>)p-R <2 > in which R<1> and R<2> in each case represent alkyl having 1-12 C atoms, where one or two non-adjacent CH2 groups can also be replaced by -O-, -CO-, -CO-O-, -O-CO- or -CH=CH-, and one of the radicals R<1> and R<2> can also represent H, F, Cl, Br, CN or -Q<4>-R<3>, Q<1> and Q<2> in each case represent 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,3-dithiane-2,5-diyl or 1,4-bicyclo(2,2,2)octylene, Q<3> and Q<4> in each case represent 1,4-phenylene, pyrimidine-2,5-diyl, pyridazine-3,6-diyl or the corresponding N-oxide, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,3-dithiane-2,5-diyl or 1,4-bicyclo(2,2,2)octylene, each of which is unsubstituted or substituted by 1 or 2 F, Cl and/or Br atoms and/or CH3 and/or CN groups, R<3> represents alkyl having 1-12 C atoms, where one or two non-adjacent CH2 groups can also be replaced by -O-, -CO-, -CO-O-, -O-CO- or -CH=CH-, or represents F, Cl, Br or CN, Z represents -CO-O-, -O-CO-, -CH2CH2-, -O-CH2-, -CH2-O-, -O-, -CH2-, -CH=CH- or a single bond, m and n represent 0, 1 or 2 and p represents 0 or 1, the total of (m + n) being 0, 1 or 2, with the provisos that a) Z does not represent -CH=CH- if Q<3> is an aromatic ring and b) R<1> is not identical to R<2> if p = 0 and Q<1> and Q<2> in each case represent 1,4-cyclohexylene, are suitable as components in liquid-crystalline phases. |