Pyrimidines

Details Pyrimidines Pyrimidines

1986-09-12

1991-08-27

Lee, Mary C.

Compositions

Liquid crystal compositions

Containing nonsteryl liquid crystalline compound of...

544335, 544298, 359103, C09K 1934, C07D23902

Patent

active

050430939

DESCRIPTION:

BRIEF SUMMARY
The invention relates to compounds of the formula ##STR2## in which R is an alkyl group of 1-15 C atoms in which in addition one or two nonadjacent CH.sub.2 groups can be replaced by --O--, --CO--, --O--CO--, --CO--O--, --CHY-- and/or --.dbd.CH--, or is H, F, Cl or CN, CH.sub.2 groups are replaced by --O--, --CO--, --O--CO--, --CO--O--, --CHY-- and/or by --.dbd.CH--, nonadjacent CH.sub.2 groups can be replaced by --O--, --CO--, --O--CO--, --CO--O--, --CHY-- and/or --.dbd.CH--, monosubstituted or disubstituted by F and/or Cl atoms and/or CH.sub.3 groups and/or CN groups, or is a single bond, and nonadjacent and, if A is a single bond, nonterminal CH.sub.2 groups can be replaced by 0 atoms and/or --.dbd.CH--groups, with the proviso that R is an alkyl group having 1-15 C atoms, in which in addition one or two nonadjacent CH.sub.2 groups can be replaced by --O--, --O--CO--, --CO--O--and/or --.dbd.CH--, if X is --S--R.sup.2.
For simplicity, hereinafter Cy is an optionally substituted 1,4-cyclohexylene group, Phe is a 1,4-phenylene group and Pyr is a pyrimidine-2,5-diyl group.
Similar compounds are known for example from Japanese Offenlegungsschrift 56-164,169. However, the three ring compounds specified there do not, unlike the present compounds, contain saturated rings (Cy).
The compounds of the formula I, like similar compounds, can be used as components of liquid-crystalline phases, in particular for displays which are based on the principle of the twisted cell (TN displays), the guest-host effect, the effect of the deformation of aligned phases or the effect of dynamic scattering.
The invention had for its object to find new stable liquid-crystalline or mesogenic compounds which are suitable for use as components of liquid-crystalline [sic]phases.
It was found that the compounds of the formula I are highly suitable for use as components of liquid-crystalline phases. In particular, with their aid it is possible to prepare stable liquid-crystalline phases for TN displays having high multiplexing rates.
The trinuclear compounds of the formula I thereby make possible the development of highly multiplexible mixtures of very small optical anisotropy, with which a twisted cell can be operated in particular in the first Gooch-Tarry transmission minimum. The result is consequently a very small dependence of the angle of observation on the contrast. The dinuclear compounds of the formula I have particularly favorable elastic constants and an excellent low-temperature stability. By providing the compounds of the formula I, in addition, the range of liquid-crystalline substances which are suitable from various application aspects for preparing nematic mixtures is, in general, quite appreciably widened.
The compounds of the formula I have a wide application area. Depending on the choice of substituents, these compounds can serve as base materials of which liquid-crystalline dielectrics are predominantly composed; however, it is also possible to add compounds of the formula I to liquid-crystalline base materials of other compound classes, for example in order to vary the dielectric and/or optical anisotropy of such a dielectric or in order to improve the elastic properties. The compounds of the formula I are further suitable for use as intermediates for preparing other substances which can be used as constituents of liquid-crystalline dielectrics. Some of the compounds of the formula I merely exhibit monotropic liquid-crystalline properties. However, such compounds are also highly suitable for use as constituents of liquid-crystalline dielectrics.
The compounds of the formula I are colorless in the pure state and form liquid-crystalline mesophases in a temperature range which is favorable for electro-optical use. They are very stable chemically, thermally and to light.
The invention thus provides the compounds of the formula I. The invention further provides the use of the compounds of the formula I as components of liquid-crystalline phases. The invention further provides liquid-crystalline phases containing at least on

REFERENCES:
patent: 4391730 (1983-07-01), Kuschel et al.
patent: 4510069 (1985-04-01), Eidenschink et al.
patent: 4565425 (1986-01-01), Petrzilka et al.
patent: 4725688 (1988-02-01), Taguchi et al.
patent: 4780241 (1988-10-01), Furukawa et al.

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