New alk(en)-yl-terminated liquid crystal cpds. and use as achiral component - for stabilising smectic C phase in chiral tilted smectic medium used in LCD, esp. ferroelectric LCD

摘要

New liquid crystal (LC) cpds. are linear di- and tri-cyclic ester, ether or satd. or unsatd. hydrocarbon cpds. with terminal (alkoxy)alk-1-enyl gp(s)., of the formula R-(-CX=CY-) -(A1-Z1) -A2-Z2-(-CX=CY-) -R' (I): and R' = 1-15 C alkyl, opt. with halogen substit(s)., in which one or more non-adjacent CH2 gps. may be replaced by -O-; 1-2 = (a) trans-1,4-cyclohexylene, in which one or more non-adjacent CH2 gps. may be replaced by -O- and/or -S-; (b) 1,4-phenylene, in which one or two CH gps. may be replaced by N; or (c) 1,4-cyclohexenylene, 1,4-bicyclo(2,2,2)-octylene, piperidin-1,4-diyl, naphthalen-2,6-diyl, decahydronaphthalen-2,6-diyl or 1,2,3,4-tetrahydronaphthalen-2,6-diyl; and gps. (a) and (b) may be substd. by F; 1-2 = -CO-O-, -O-CO-, CH2O-, -OCH2-, -(CH2)4-, -CH=CH-CH2Ch2-, -C=C- or a single bond; and Y = H, F or Cl; s and o = 0 or 1 and s = o = 1 or more; m = 1 or 2. (I) can be prepd. (not claimed) by standard method, e.g. as described in Houben-Weyl, Methoden der organischen Chemie, Georg-Thieme-Verlag, Stuttgart. Examples are given in the text (see below).