Liquid crystal propene or propenyl nitrile derivatives

Details Liquid crystal propene or propenyl nitrile derivatives Liquid crystal propene or propenyl nitrile derivatives

2000-01-24

2002-09-03

Wu, Shean C. (Department: 1756)

Stock material or miscellaneous articles

Liquid crystal optical display having layer of specified...

C252S299610, C252S299620, C252S299630, C252S299660, C544S242000, C544S335000, C546S350000, C549S369000, C558S401000

Reexamination Certificate

active

06444279

ABSTRACT:

The present invention relates to acetylene derivatives of the formula I
in which
R is an alkyl or alkenyl radical having 1 to 15 carbon atoms which is unsubstituted, mono-substituted by CN or CF
3
so at least monosubstituted by halogen, where, in addition, one or more —CH
2
— groups in these radicals may be replaced, in each case independently of one another, by —O—, —S—,
—CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another,
A
1
and A
2
are each, independently of one another,
(a) a trans-1,4-cyclohexylene radical, in which, in addition, one or more non-adjacent —CH
2
— groups may be replaced by —O— and/or —S—,
(b) a 1,4-phenylene radical, in which, in addition, one so two CH groups may be replaced by N,
(c) trans-1,4-cyclohexenylene,
(d) a radical from the group consisting of 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl,
where the radicals (a) to (c) may be monosubstituted or disubstituted by fluorine or CH
3
,
Z
1
, Z
2
and Z
3
are each, independently of one another, —CO—O—, —O—CO—, —CH
2
O—, —OCH
2
—, —CH
2
CH
2
—, —CH═CH—, —C≡C—, —(CH
2
)
4
—, —OCF
2
—, —CF
2
O—, —CH═CH—CH
2
CH
2
— or a single bond,
m is 0, 1 or 2,
n is 0 or 1,
L
1
, L
2
and L
3
are each, independently of one another, H or F, and
Y is —C≡C—, —CH═CH—, —CF═CH—, —CH═CF— or —CF═CF—,
with the proviso that, in the case where
Y=—C≡C— or —CH═CH—,
a) n=1 and Z
3
is a single bond
or
b) L
1
and/or L
2
is/are fluorine
or
c) R is alkenyl or alkenyloxy having 2 to 12 carbon atoms
or
d) A
2
is a pyridine radical, a pyrimidine radical or a trans-1,4-cyclohexylene radical which is monosubstituted or disubstituted by fluorine or CH
3
or
e) one of the radicals Z
1
, Z
2
or Z
3
is —CO—O—.
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 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 or the effect of dynamic scattering.
The invention has the object of finding novel, stable, liquid-crystalline or mesogenic compounds which are suitable as components of liquid-crystalline media and in particular simultaneously have 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 high &Dgr;∈ values at the same time as high clearing points. They can be used to obtain stable liquid-crystalline media having a broad mesophase range and advantageous optical and dielectric anisotropy values. These media furthermore have very good low-temperature behaviour.
Compounds of the formula
are disclosed, for example, in JP 55-149371, JP 55-009012, JP 55-011529, PL 137 995 and PL 138 286.
Cyanoethyne derivatives of the formula
are disclosed in JP 59-190 958 A2, JP 60-169 455 A2, JP 60-188 358 A2 and JP 60-019 756 A2.
Biphenylacetylenes of the formula
are described in DE 32 46 440 A1.
However, the fluorinated compounds according to the invention are not mentioned therein.
However, in view of the extremely wide variety of areas of application of such compounds of high &Dgr;∈, it was desirable to have available further compounds of high nematogeneity which have properties which are 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 of which liquid-crystalline media are predominantly composed; however, compounds of the formula I can also be added 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 generally form liquid-crystalline mesophases in a temperature range which is favourably located for electro-optical use. The compounds according to the invention are stable chemically and thermally.
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 comprising 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.
For reasons of simplicity, A
4
and A
3
below denote a radical of the formula
and
respectively, Cyc 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 Bi denotes a bicyclo[2.2.2]octylene radical, where Cyc and/or Phe may be unsubstituted or monosubstituted or disubstituted by F or CN.
A
1
and A
2
are preferably selected from the group consisting of Cyc, Che, Phe, Pyr, Pyd and Dio.
Accordingly, the compounds of the formula I include bicyclic compounds of the sub-formulae Ia and Ib:
R-A
2
-A
4
-Y-CN
la
R-A
2
-Z
2
A
4
-Y-CN
lb
tricyclic compounds of the sub-formulae Ic to Ig
R-A
1
-A
2
-A
4
-Y-CN
lc
R-A
1
-Z
1
-A
2
-A
4
-Y-CN
ld
R-A
1
-A
2
-Z
2
-A
4
-Y-CN
le
R-A
1
-A
2
-A
4
-Y-CN
lf
R-A
1
-Z
1
-A
3
-A
4
-Y-CN
lg
and tetracyclic compounds of the sub-formulae Ih to Ik:
R-A
1
-A
2
-A
3
-A
4
-Y-CN
lh
R-A
1
-Z
1
-A
2
-A
3
-A
4
-Y-CN
li
R-A
1
-A
2
-Z
2
-A
3
-A
4
-Y-CN
lj
R-A
1
-Z
1
-A
2
-Z
2
-A
3
-A
4
-Y-CN
lk
Y is preferably —C≡C—, furthermore —CF═CF— or —CF═CH—. Preference is also given to compounds of the formula I and of all sub-formulae in which A
1
, A
2
, A
3
and/or A
4
are 1,4-phenylene which is monosubstituted or disubstituted by F. In particular, these are 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene and 3,5-difluoro-1,4-phenylene.
A
1
and A
2
are preferably
Z
1
, Z
2
and Z
3
are preferably a single bond, —CO—O—, —O—CO— or —CH
2
CH
2
—, secondarily preferably —CF
2
O—, —OCF
2
—, —CH
2
O— or —OCH
2
—. If one of the radicals Z
1
, Z
2
and Z
3
is —(CH
2
)
4
— or —CH═CH—CH
2
CH
2
—, the other radical Z
1
or Z
2
or Z
3
(if present) is preferably a single bond.
m and n are preferably 1 or 0, particular preference being given to compounds in which m=n=0, furthermore those in which m+n=1.
If R is an alkyl radical and/or an alkoxy radical, this can be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and accordingly is preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, furthermore methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy.
Oxaalkyl is preferably straight-chain 2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.
If R is an alkyl radical in which one —CH
2
— group has been replaced by —CH═CH—, this can be straight-chain or branched. I

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