New di:fluoro-allyl-benzene cpds. and use in liquid crystal media - esp. dielectric for electrical optical display with favourable optical and dielectric anisotropy and good low temp. property

摘要

New difluoroallyl-terminated benzene derivs. are of formula (I): R = H, 1-15C alk(en)yl, opt. with 1 CN or CF3 or at least 1 halogen substit., in which 1 or more CH2 gps. may be replaced by -O-, -S-, 1,3-cyclobutylene, -CO-, -CO-O-, -O-CO- or -O-CO-O, without directly linked O atoms; L1-2 = H or F; A1-2 = (a) trans-1,4-cyclohexylene (Cyc), in which 1 or more non-adjacent CH2 gps. may be replaced by -O- and/or -S-; 1,4-phenylene (Phe), in which 1 or 2 CH gps. may be replaced by N; or (C) 1,4-cyclohexenylene, 1,4-bicyclo(2,2,2)octylene, piperidin-1,4-diyl, naphth-2,6-diyl, decanhydronaphth-2,6-diyl and 1,2,3,4-tetrahydronapth-2,6-diyl; and gps. (a) and (b) may have 1 or 2 F substits.; Z1-2 = -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CH2CH2-, -CH=CH-, or a single bond and one of Z1-2 may also - -(CH2)4- or -CH=CH-CH2CH2-; Y = -O-, -S-, -CH2-, -CHF-, -CF2-, -CO-, -OCH2-, -CH2O-, -OCF2-, -CF2O-, -CH2CH2-, -CF2CH2-, -COCH2-, -COO- or a single bond; Z = -CF2-CH=CH2 or -CH2-CH=CF2; m = 0, 1 or 2. (I) can be prepd. by standard methods, e.g. as described in Houben-Weyl, Methoden der Organischen Cehmie, Georg-Thieme-Verlag, Stuttgart. (I) with Y = -O- can be prepd. by metallising the 2-unsubstd. benzene deriv. (-Y-Z = H) and electrophilic reaction. Examples are given in the text. Z1 = a single bond; L1 - F; Y = -O- or a single bond. USE/ADVANTAGE - (I) are used as components of liquid crystal (LC) media, which are used in LCDs, esp. as dielectrics in electrooptical displays. They are esp. useful in displays of the twisted cell, guest-host, deformation aligned phase or dynamic scattering type. (I) are stable, LC or mesogenic cpds. with relatively low viscosity and high dielectric anisotropy. LC media contg. (I) are stable and have relatively low viscosity, a wide mesophase range, advantageous optical and dielectric anisotropy and very good low temp. properties.