Cyclohexane derivatives and liquid-crystalline medium

Details Cyclohexane derivatives and liquid-crystalline medium Cyclohexane derivatives and liquid-crystalline medium

2001-06-28

2003-04-22

Wu, Shean C. (Department: 1756)

Stock material or miscellaneous articles

Liquid crystal optical display having layer of specified...

C252S299630, C560S065000, C570S127000, C570S128000, C570S130000, C570S131000

Reexamination Certificate

active

06551666

ABSTRACT:

The invention relates to novel cyclohexane derivatives of the formula I
in which
Y is alkyl or alkoxy having 1 to 10 carbon atoms which is unsubstituted or at least monosubstituted by halogen up to perhalo, is alkenyl or alkenyloxy having 2 to 10 carbon atoms which is unsubstituted or at least monosubstituted by —CN, —CF
3
or —F, or is —CN, —F, —OCHF
2
, —OCF
3
, —OCHFCF
3
or —OCF
2
CF
3
,
one of X
1
and
X
2
is CF
3
, CHF
2
, CH
2
F, OCHF
2
, OCF
3
, SF
5
or an alkyl radical having 2 to 10 carbon atoms which is monosubstituted or polysubstituted by fluorine or chlorine, and one of X
1
or X
2
in each cyclohexane ring is H,
R
1
is H, an alkyl or alkenyl radical having 1 to 12 carbon atoms which is unsubstituted, monosubstituted by CN or CF
3
or at least monosubstituted by halogen, where one or more non-adjacent CH
2
groups in these radicals may also, in each case independently of one another, be replaced by
A
1
and A
2
, independently of one another, are
a) a trans-1,4-cyclohexylene radical, in which, in addition, one or more, preferably up to two, non-adjacent CH
2
groups may be replaced by —O— and/or —S—,
b) a 1,4-phenylene radical, in which, in addition, one or two CH groups may be replaced by N,
c) a radical from the group consisting of 1,4-bicyclo[2.2.2]-octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, deca-hydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydro-naphthalene-2,6-diyl,
d) 1,4-cyclohexenylene,
where the radicals a), b) and d) may be substituted by CN, Cl or F, e.g., 0-4 times,
Z
1
, Z
2
are each, independently of one another, —CO—O—, —O—CO—,
and Z
3
—CH
2
O—, —O—, —O—CH
2
—, —CH
2
CH
2
—, —CH═CH—, —C≡C—, —CF
2
CF
2
—CF
2
O—, —OCF
2
— or a single bond,
n and m, independently of one another, are 0, 1, 2 or 3,
and
p is 0, 1, 2 or 3,
where
m+n+p is 1, 2, 3 or 4.
The invention also relates to the use of the compounds of the formula I as components of liquid-crystalline media, and to liquid-crystal and electro-optical display elements which contain the liquid-crystalline media according 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 DAP or ECB (electrically controlled birefringence) or the effect of dynamic scattering.
The substances employed hitherto for this purpose all have certain disadvantages, for example inadequate stability to the action of heat, light or electric fields, or unfavorable elastic and/or dielectric properties.
Similar compounds have already been disclosed in DE 19723276. However, this document only relates to compounds having axial F, Cl or CN, which are not covered by the present application. The laterally substituted cyclohexane derivatives covered by DE 3510432 preferably have equatorially arranged substituents. However, the subject-matter of the present application differs through the nature of the substituents.
The invention had the object of finding novel stable liquid-crystalline or mesogenic compounds having negative or low positive dielectric anisotropy which are suitable as components of liquid-crystalline media, in particular for TFT and STN displays.
It has now been found that the compounds of the formula I are eminently suitable as components of liquid-crystalline media. They can be used to obtain stable liquid-crystalline media, in particular suitable for TFT or STN displays. The novel compounds are distinguished, in particular, by high thermal stability, which is advantageous for a high holding ratio, and exhibit favorable clearing point values. Preferred compounds of the formula I have negative dielectric anisotropy and are therefore particularly suitable for displays based on the effect of deformation of aligned phases.
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 may serve as base materials of 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 optimise its threshold voltage and/or its viscosity. The meaning of the formula I covers all isotopes of the chemical elements bound in the compounds of the formula I. The meaning of the formula I likewise covers both enantiomers of the respective compounds of the formula I. In enantiomerically pure or enriched form, the compounds of the formula I are also suitable as chiral dopants and in general for achieving chiral mesophases. One of ordinary skill can, with routine experimentation, determine the characteristics and properties needed to optimize the compounds and mixtures for use in these and other displays, as is wholly conventional in the art.
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 having a content of at least one compound of the formula I and to liquid-crystal display elements, in particular electro-optical display elements, which contain media of this type.
Above and below, n, m, p, R
1
, X
1
, X
2
, Z
1
, Z
2
, Z
3
, A
1
A
2
and Y are as defined above, unless expressly stated otherwise. If the radical X
1
occurs more than once, it may adopt identical or different meanings. The same applies to X
2
, A
1
, A
2
, Z
1
, Z
2
and Z
3
.
For reasons of simplicity, Cyc below denotes a 1,4-cyclohexylene radical, Che denotes a 1,4-cyclohexenylene radical, Dio denotes a 1,3-dioxane-2,5-diyl radical, Dit denotes a 1,3-dithiane-2,5-diyl radical, Phe denotes a 1,4-phenylene radical, Pyd denotes a pyridine-2,5-diyl radical, Pyr denotes a pyrimidine-2,5-diyl radical and Bco denotes a bicyclo[2.2.2]octylene radical, where Cyc and/or Phe may be unsubstituted or monosubstituted or polysubstituted by Cl, F or CN.
W denotes the following structural unit:
in which p, X
1
, X
2
, X
3
and Z
2
are as defined above.
Formula I thus encompasses, i.a., compounds of the sub-formula Ia:
R
1
—W—Y  Ia
compounds of the sub-formulae Ib, Ic and Id:
R
1
—W—A
2
—Y  Ib
R—W—Z
3
—A
2
—Y  Ic
R
1
—A
1
—Z
1
—W—Y  Id
compounds of the sub-formulae Ie to Ii:
R
1
—W—A
2
—A
2
—Y  Ie
R
1
—W—A
2
—Z
3
—A
2
—Y  If
 R
1
—W—Z
3
—A
2
—A
2
—Y  Ig
R
1
—W—Z
3
—A
2
—Z
3
—A
2
—Y  Ih
R
1
—A
1
—Z
1
—W—A
2
—Y  Ii
and compounds of the sub-formulae Ij to Ir:
R
1
—W—A
2
—A
2
—A
2
—Y  Ij
R
1
—W—Z
3
—A
2
—A
2
—A
2
—Y  Ik
R
1
—W—A
2
—Z
3
—A
2
—A
2
—Y  II
R
1
—W—A
2
—A
2
—Z
3
—A
2
—Y  Im
R
1
—W—Z
3
—A
2
—Z
3
—A
2
—A
2
—Y  In
R
1
—W—Z
3
—A
2
—A
2
—Z
3
—A
2
—Y  Io
R
1
—W—A
2
—Z
3
—A
2
—Z
3
—A
2
—Y  Ip
R
1
—W—Z
3
—A
2
—Z
3
—A
2
—Z
3
—A
2
—Y  Iq
R
1
—A
1
—Z
1
—W—A
2
—Z
2
—A
2
—Y  Ir
Of these, particular preference is given to those of the sub-formulae Ia, Ib, Id, Ie, If, Ih, Ii and Ij.
The preferred compounds of the sub-formula Ib include those of the sub-formulae Iba and Ibb:
R
1
—W-Phe-Y  Iba
R
1
—W-Cyc-Y  Ibb.
The preferred compounds of the sub-formula Ic include those of the sub-formulae Ica and Icb:
R
1
—W—Z
3
-Phe-Y  Ica
R
1
—W—Z
3
-Cyc-Y  Icb.
The preferred compounds of the sub-formula Id include those of the sub-formulae Ida and Idb:

Affiliated with

Also associated with

Rating

Cyclohexane derivatives and liquid-crystalline medium does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Cyclohexane derivatives and liquid-crystalline medium, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cyclohexane derivatives and liquid-crystalline medium will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3009707