Compositions – Liquid crystal compositions – Containing nonsteryl liquid crystalline compound of...
Reexamination Certificate
2000-01-18
2001-05-15
Kelly, C. H. (Department: 1743)
Compositions
Liquid crystal compositions
Containing nonsteryl liquid crystalline compound of...
C546S146000, C546S200000, C546S202000, C546S225000, C546S230000, C546S215000, C556S405000, C548S237000
Reexamination Certificate
active
06231786
ABSTRACT:
Besides nematic and cholesteric liquid crystals, optically active, tilted, smectic (ferroelectric) liquid crystals have also recently been used in commercial display devices.
Clark and Lagerwall have been able to show that the use of ferroelectric liquid crystals (FLCs) in very thin cells results in opto-electrical switching or display elements which have response times which are faster by a factor of up to 1000 compared with conventional TN (“twisted nematic”) cells (see, for example, EP-A 0 032 362). Owing to this and other favorable properties, for example the possibility of bistable switching and the virtually viewing angle-independent contrast, FLCs are basically highly suitable for areas of application such as computer displays.
For a more detailed explanation of the technical requirements of FLCs, see European Patent Application 97118671.3 and DE-A 197 48 432.
Azole derivatives have already been described for use in liquid-crystal mixtures: thiadiazole derivatives, for example in EP-A 0 309 514, EP-A 0 335 348, U.S. Pat. No. 5,076,961, U.S. Pat. No. 5,200,109; 1,3-thiazole derivatives, for example in EP-A 0 309 514, EP-A 0 439 170; benzothiazole derivatives, for example in JP-A 09-059266, isoxazoles, for example in JP-A 10-333113.
However, since the development, in particular of ferroelectric liquid-crystal mixtures, can in no way be regarded as complete, the manufacturers of displays are interested in a very wide variety of components for mixtures, partly because only the interaction of the liquid-crystalline mixtures with the individual components of the display device or of the cells (for example the alignment layer) allows conclusions to be drawn on the quality of the liquid crystalline mixtures too.
Surprisingly, it has now been found that fluorinated azoles of the formula (I), even when admixed in small amounts, have a favorable effect on the properties of liquid-crystal mixtures, in particular chiral smectic mixtures, for example regarding the dielectric anisotropy and/or the melting point, but also regarding the switching behavior.
The invention therefore relates to fluorinated azoles of the formula (I)
R
1
(—A
1
)
a
—T—(A
2
—)
b
(M—A
3
—)
C
R
2
(I)
where the symbols and indices have the following meanings:
T is undirected and is
4-fluorothiazole-2,5-diyl, 5-fluorothiazole-2,4-diyl, 4-fluorooxazole-2,5-diyl, 5-fluorooxazole-2,4-diyl or 4-fluoroisoxazole-2,5-diyl;
R
1
and R
2
are identical or different and are
hydrogen or a straight-chain or branched C
1-20
-alkyl or C
2-20
-alkenyl radical (with or without asymmetrical carbon atoms), where
a) one or two nonterminal CH
2
groups may be replaced by —O— and/or —C(═O)—, with the proviso that two adjacent CH
2
groups cannot be replaced by heteroatoms, and/or
b) one or more CH
2
groups may be replaced by —CH═CH— and/or —C≡C—, and/or
c) one CH
2
group may be replaced by —Si(CH
3
)
2
—, cyclopropane-1,2-diyl, cyclobutane-1,3-diyl, cyclopentane-1,4-diyl, bicyclo[1.1.1]pentane-1,3-diyl or cyclohexane-1,4-diyl, and/or
d) one or more H atoms may be replaced by F and/or CN;
e) in the case of a straight-chain or branched alkyl radical containing asymmetrical carbon atoms, the asymmetrical carbon atoms either have —CH
3
, —OCH
3
, —CF
3
, F, CN and/or C
1
as substituents, or are incorporated into a 3- to 7-membered ring, in which, in addition, one or two non-adjacent CH
2
groups may be replaced by —O— and one CH
2
group may be replaced by —OC(═O)—;
A
1
, A
2
and A
3
are identical or different and are
phenylene-1,4- diyl, unsubstituted or monosubstituted or disubstituted by CN or F, phenylene-1,3-diyl, unsubstituted or monosubstituted or disubstituted by CN or F, cyclohexane-1,4diyl, in which one or two H atoms may be replaced by CN and/or CH
3
and/or F, 1-cyclohexene-1,4-diyl, in which one H atom may be replaced by F, 1-alkyl-1silacyclohexane-1,4-diyl, pyridine-2,5-diyl, unsubstituted or monosubstituted by F, pyrimidine-2,5-diyl, unsubstituted or monosubstituted by F, or thiophene-2,5-diyl;
M is undirected and is
—OC(═O)—, —OCH
2
—, —CH
2
CH
2
—, —OC(═O)CH
2
CH
2
—, —OCH
2
CH
2
CH
2
—, —C≡C—, —CH
2
CH
2
CH
2
CH
2
— or a single bond;
a, b and c, independently of one another, are 0 or 1, with the proviso that the sum a+b+c is 1 or 2.
For example, b+1, and a+c is at least 1.
According to an embodiment of the invention, R
1
and R
2
cannot be alkenyl radicals or, with the above provisos e), straight-chain alkyl radicals.
For use in liquid-crystal mixtures, preference is given to the following compounds of the formulae (I-1) to (I-9):
in which:
R
3
and R
4
, independently of one another, are hydrogen or a straight-chain or branched alkyl radical (with or without asymmetrical carbon atoms) having 1 to 16 carbon atoms, in which, in addition, one nonterminal CH
2
group may be replaced by —O— or, undirected, —OC(═O)— and in which one or more H atoms may be replaced by F;
R
5
is hydrogen or a straight-chain or branched alkyl radical (with or without asymmetrical carbon atoms) having 1 to 16 carbon atoms, in which, in addition, one nonterminal CH
2
group which is not directly adjacent to the ring may be replaced by —O— or, undirected, —OC(═O)— and in which one or more H atoms may be replaced by F.
Particular preference is given to the compounds of the formula (I-1) in which R
3
and R
4
are a straight-chain alkyl radical having 2 to 12 carbon atoms.
Particular preference is likewise given to the compounds of the formula (I-1) in which R
3
or R
4
is hydrogen and the other radical R
3
or R
4
is a straight-chain alkyl or alkoxy radical having 2 to 12 carbon atoms.
Particular preference is likewise given to the compounds of the formula (I-1) in which R
3
or R
4
is a straight-chain alkyl radical having 2 to 12 carbon atoms and the other radical R
3
or R
4
is a straight-chain alkoxy radical having 2 to 12 carbon atoms.
Particular preference is likewise given to the compounds of the formula (I-1) in which R
3
or R
4
is an alkanoyloxy radical having 2 to 12 carbon atoms and the other radical is an alkyl radical having 1 to 12 carbon atoms.
Particular preference is likewise given to the compounds of the formula (I-2) in which R
3
is a straight-chain alkyl or alkoxy radical having 2 to 12 carbon atoms and R
5
is hydrogen or a straight-chain alkyl radical having 1 to 12 carbon atoms.
Particular preference is likewise given to the compounds of the formula (I-8) in which R
3
and R
4
are straight-chain alkyl or alkoxy radicals having 1 to 12 carbon atoms.
Particular preference is likewise given to the compounds of the formula (I-9) in which R
3
and R
4
are straight-chain alkyl or alkoxy radicals having 1 to 12 carbon atoms.
Of the compounds of the formula (I) which are to be used as optically active components (dopants), preference is given to those containing the following groups:
a) —C*H(CH
3
)C
m
H
2m+1
, where m has a value of from 2 to 8
b) —OC*H(CH
3
)C
m
H
2m+1
, where m has a value of from 2 to 8
c) —OC*H(CH
3
)CO
2
C
m
H
2m+1
, where m has a value of from 1 to 10
d) —OC(═O)C*H(CH
3
)OC
m
H
2m+1
, where m has a value of from 1 to 10
e) —OC(═O)C*H(F)C
m
H
2m+1
, where m has a value of from 1 to 10
f) —OCH
2
C*H(F)C
m
H
2m+1
, where m has a value of from 1 to 10
g) —OCH
2
C*H(F)C*H(F)C
m
H
2m+1
, where m has a value of from 1 to 10
in which C* denotes the asymmetrical carbon atom.
The compounds of the formula (I) can also be employed for the production of medicaments/pharmaceuticals and crop-protection products/agrochemicals.
For use as a component of agrochemicals or pharmaceuticals or alternatively as an intermediate in the production of agrochemicals or pharmaceuticals, preference is given to the compounds of the formula (I) in which
T, A
2
, R
1
and R
2
are as defined above, and
a and c are each zero.
Particular preference is given in this context to the compounds in which T is 4-fluorothiazole-2,5-diyl or 4-fluorooxazole-2,5-diyl.
The compounds according to the invention
Hornung Barbara
Ogawa Ayako
Schmidt Wolfgang
Wingen Rainer
Clariant GmbH
Frommer & Lawrence & Haug LLP
Kelly C. H.
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