Compositions – Liquid crystal compositions – Containing nonsteryl liquid crystalline compound of...
Patent
1995-09-12
1997-07-01
Wu, Shean C.
Compositions
Liquid crystal compositions
Containing nonsteryl liquid crystalline compound of...
25229961, 25229962, 25229966, 25229967, 349182, 544298, 549369, 549370, 560 65, 560100, 560102, 570127, 570129, 570144, 568588, 568634, C09K 1930, C09K 1912, C07C 2513, C07C 4302
Patent
active
056434952
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP94/00767 filed Mar. 11, 1994.
The invention relates to 1,2,2,2-tetrafluoroethyl ethers of the formula I --O--CHF--CF.sub.3 I unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, it also being possible for one or more CH.sub.2 groups in these radicals to be replaced, in each case independently of one another, by --O--, --S--, ##STR1## --CO--, --CO--O--, --O--CO-- or --O--CO--O-- in such a way that O atoms are not linked directly to one another, non-adjacent CH.sub.2 groups can be replaced by --O-- and/or --S--, be replaced by N, 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphtalene -2,6-diyl, atoms, --O--CO--, --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --CH.dbd.CH--, --C.tbd.C-- or a single bond, and one of the radicals Z.sup.1 and Z.sup.2 is alternatively --(CH.sub.2).sub.4 -- or --CH.dbd.CH--CH.sub.2 CH.sub.2 --, and
The invention furthermore relates to the use of these compounds as components of liquid-crystalline media and to liquid-crystal and electro-optical display elements containing the liquid-crystalline media according ing to the invention.
The compounds of the formula I can be used as components of liquid-crystalline media, in particular for displays based on the principle of the twisted cell, the guest-host effect, the effect of deformation of aligned phases or the effect of dynamic scattering.
The invention had the object of finding novel, stable, liquid-crystalline or mesogenic compounds which are suitable as components of liquid-crystalline media and in particular have at the same time comparatively low viscosity and relatively high dielectric anisotropy.
It has now been found that compounds of the formula I are eminently suitable as components of liquid-crystalline media. In particular, they have comparatively low viscosities. They can be used to obtain stable liquid-crystalline media having a broad mesophase range and advantageous values for the optical and dielectric anisotropy. Furthermore, these media have very good low-temperature behaviour.
In the general formula, WO 88/00335 covers the compounds of the formula I, but the compounds according to the invention are not mentioned therein.
DE-A 41 04 126 describes compounds containing a terminal O--CH.sub.2 --CF.sub.3 or O--CH.sub.2 --CH.sub.2 F group, such as, for example, ##STR2##
However, in view of the very wide range of areas of application of such compounds having high .DELTA..epsilon., it was desirable to have available further compounds of high nematogeneity which have properties precisely customized to the particular applications.
In addition, the provision of compounds of the formula I very generally considerably broadens the range of liquid-crystalline substances which are suitable, from various applicational points of view, for the preparation of liquid-crystalline mixtures.
The compounds of the formula I have a broad range of applications. Depending on the choice of substituents, these compounds can be used as base materials from which liquid-crystalline media are predominantly composed; however, it is also possible to add compounds of the formula I to liquid-crystalline base materials from other classes of compound in order, for example, to modify the dielectric and/or optical anisotropy of a dielectric of this type and/or to optimize its threshold voltage and/or its viscosity.
In the pure state, the compounds of the formula I are colorless and form liquid-crystalline mesophases in a temperature range which is favourably located for electro-optical use. They are stable chemically, thermally and to light.
The invention thus relates to the compounds of the formula I and to the use of these compounds as components of liquid-crystalline media. The invention furthermore relates to liquid-crystalline media containing at least one compound of the formula I and to liquid-crystal display elements, in particular electro-optical display elements, containing media of this type
REFERENCES:
patent: 5051527 (1991-09-01), Suzuki et al.
patent: 5389289 (1995-02-01), Rieger et al.
patent: 5409637 (1995-04-01), Rieger et al.
patent: 5422035 (1995-06-01), Bartmann et al.
patent: 5458806 (1995-10-01), Bartmann et al.
Bartmann Ekkehard
Finkenzeller Ulrich
Merck Patent Gesellschaft mit beschrankter Haftung
Wu Shean C.
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