New 2,5-di:substd. 1,3-dioxan cpds. with (phenyl-)cyclohexyl gp. - are components of liq. crystal media for twisted cell devices, with high stability, good solubility, etc.

摘要

1,3-Dioxan derivs. of formula (I) are new: Q = CHal H(3=l); OCnH(2n+1) or CH=CH CnH(2n+1); Hal = F or Cl; l = 1-3; n and r = 0-5; Xa = Xb = O and Ya = Yb = Ch2; Xa = Xb = CH2 and Ya = Yb = 0; Z1 and Z2 = C2H4 or single bond; A1 = trans-1,4-cyclohexylene or 1,4-phenylene (or its 3-fluoro or 3,5-difluoro- deriv.); m = 0-2; X = F, Cl, CF3, CN, OCF3 or OCHF2; Y and Z are each H or F. Z1 and Z2 = bond, Ya and Yb = 0; and Q = CH2Hal, OMe or CH = CH2. Pref. X = F, Cl, CF3 or OCF3; (a) Y = H or F and Z = H; (b) Y = F and Z = 6-F; m = zero; r = 2-4 or also 1 when Q is CH = CH2. USE/ADVANTAGE - (I) are useful as components of liq. crystals media for electrooptical displays, esp. those operating on the twisted cell principle. They provide media which remain nematic down to low temps., have excellent chemical stability and elastic properties; low threshold voltage (and its temp. dependence), and/or low optical anisotropy. (I) are colourless; readily soluble in other media components; have high positive dielectric anisotropy and favourable viscosity properties. They provide super twist devices having a very steep slope to the electrooptical characteristic.