LIQUID CRYSTAL DISPLAYS AND LIQUID CRYSTALLINE MEDIA WITH HOMEOTROPIC ALIGNMENT

Abstract

The present invention relates to liquid-crystalline media (LC media) having negative or positive dielectric anisotropy comprising self-aligning mesogens (SAMs) which effect homeotropic (vertical) alignment of the LC media at a surface or the cell walls of a liquid-crystal display (LC display). The invention therefore also encompasses LC displays having homeotropic alignment of the liquid-crystalline medium (LC medium) without conventional imide alignment layers. The LC media may be supplemented by a polymerisable or polymerised component, which serves for stabilisation of the alignment, for adjustment of the tilt angle and/or as passivation layer.

Claims

1. A LC medium comprising a low-molecular-weight liquid-crystalline component and at least one organic compound, where at least one organic compound contains at least one polar anchor group and at least one ring group, the polar anchor group of the organic compound contains at least one OH structure or an N atom in a primary or secondary or tertiary amino group, said LC medium being nematic, and wherein the organic compound encompasses a compound of the formula MESR.sup.2, in which MES denotes a mesogenic group containing at least one ring system, and R.sup.2 denotes a polar anchor group encompassing a group of sub-formula (A1)
-Sp-[X.sup.2Z.sup.3].sub.kX.sup.1(A1) in which Sp denotes a spacer group, X.sup.1 denotes a group NH.sub.2, NHR.sup.11, NR.sup.11.sub.2, OR.sup.11, OH, (CO)OH or a group of the formula ##STR00358## R.sup.0 denotes H or alkyl having 1 to 12 C atoms, X.sup.2 in each case independently denotes NH, NR.sup.11, O or a single bond, Z.sup.3 in each case independently denotes an alkylene group having 1-15 C atoms, carbocyclic rings having 5 or 6 C atoms, or combinations of one or more rings and alkylene groups, in each of which hydrogen may be replaced by OH, OR.sup.11, (CO)OH, NH.sub.2, NHR.sup.11, NR.sup.11.sub.2 or halogen, R.sup.11 in each case independently denotes a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in this radical may each be replaced, independently of one another, by CC, CHCH, (CO)O, O(CO), (CO) or O in such a way that O atoms are not linked directly to one another, and where two radicals R.sup.11 may be linked to one another to form a ring, and k denotes 0, 1, 2 or 3.

2. The LC medium according to claim 1, additionally comprising a polymerizable or polymerized component, where the polymerized component is obtainable by polymerization of a polymerizable component.

3. The LC medium according to claim 1, wherein the organic compound has a relative molar mass of greater than 100 g/mol.

4. (canceled)

5. (canceled)

6. (canceled)

7. (canceled)

8. (canceled)

9. (canceled)

10. The LC medium according to claim 1, comprising compounds of the formula I in a concentration of less than 10% by weight.

11. The LC medium according to claim 1, comprising one or more polymerizable compounds of the formula M or a polymerized component which comprises one or more compounds of the formula M in polymerized form:
P.sup.a-(Sp.sup.a).sub.s1-A.sup.2(Z.sup.1-A.sup.1).sub.n-(Sp.sup.b).sub.s2-P.sup.bM in which the individual radicals have the following meanings: P.sup.a, P.sup.b each, independently of one another, denote a polymerizable group, Sp.sup.a, Sp.sup.b on each occurrence, identically or differently, denote a spacer group, s1, s2 each, independently of one another, denote 0 or 1, A.sup.1, A.sup.2 each, independently of one another, denote a radical: a) trans-1,4-cyclohexylene, 1,4-cyclohexenylene or 4,4-bicyclohexylene, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by O and/or S and in which, in addition, one or more H atoms may be replaced by F, b) 1,4-phenylene or 1,3-phenylene, in which, in addition, one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by L, c) tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl or selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, d) saturated, partially unsaturated or fully unsaturated, and optionally substituted, polycyclic radicals having 5 to 20 cyclic C atoms, one or more of which may, in addition, be replaced by heteroatoms, n denotes 0, 1, 2 or 3, Z.sup.1 in each case, independently of one another, denotes COO, OCO, CH.sub.2O, OCH.sub.2, CF.sub.2O, OCF.sub.2, or (CH.sub.2).sub.n, where n is 2, 3 or 4, O, CO, C(R.sup.yR.sup.z), CH.sub.2CF.sub.2, CF.sub.2CF.sub.2 or a single bond, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF.sub.5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms.

12. The LC medium according to claim 1, wherein the organic compound contains one or more polymerizable groups.

13. A LC display comprising an LC cell having two substrates and at least two electrodes, where at least one substrate is transparent to light and at least one substrate has one or two electrodes, and a layer of an LC medium according to claim 1 located between the substrates, where the organic compound is suitable for effecting homeotropic alignment of the LC medium with respect to the substrate surfaces.

14. The LC display according to claim 13, wherein the substrates have no alignment layers for homeotropic alignment.

15. The LC display according to claim 13, wherein the substrates have unrubbed alignment layers on one or both sides.

16. The LC display according to claim 13, that is a VA display containing an LC medium having negative dielectric anisotropy and electrodes arranged on opposite substrates.

17. The LC display according to claim 13, that is a VA-IPS display containing an LC medium having positive dielectric anisotropy and interdigital electrodes arranged on at least one substrate.

18. A process for the preparation of an LC medium according to claim 1, comprising mixing one or more organic compounds containing at least one polar anchor group and at least one ring group with a low-molecular-weight liquid-crystalline component, and one or more polymerizable compounds and/or additives are optionally added.

19. (canceled)

20. (canceled)

21. (canceled)

22. A process for the production of an LC display comprising an LC cell having two substrates and at least two electrodes, where at least one substrate is transparent to light and at least one substrate has one or two electrodes, comprising: filling of the cell with an LC medium comprising a low-molecular-weight liquid-crystalline component, a polymerizable component and an organic compound containing at least one polar anchor group according to claim 1 which is suitable for effecting homeotropic (vertical) alignment of the LC medium with respect to the substrate surfaces, and optionally polymerization of the polymerizable component, optionally with application of a voltage to the cell or under the action of an electric field.

23. The LC medium according to claim 1, wherein the polycyclic radicals having 5 to 20 cyclic C atoms are bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]-heptane-2,6-diyl, ##STR00359## where, in addition, one or more H atoms in these radicals may be replaced by L, and/or one or more double bonds may be replaced by single bonds, and/or one or more CH groups may be replaced by N, M denotes O, S, CH.sub.2, CHY.sup.1 or CY.sup.1Y.sup.2, R.sup.00 is H, F, straight-chain or branched alkyl having 1 to 12 C atoms in which one or more H atoms are optionally replaced by F, and Y.sup.1 and Y.sup.2 each, independently of one another, are H, F or straight-chain or branched alkyl having 1 to 12 C atoms, in which, in addition, one or more H atoms may be replaced by F, or denote Cl or CN.

Description

EXAMPLES

[0359] The compounds employed, if not commercially available, are synthesised by standard laboratory procedures. The LC media originate from Merck KGaA, Germany.

Synthesis Examples

Example 1: N-[2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl]-ethane-1,2-diamine

1.1 4-Bromo-3-fluoro-4-methoxybiphenyl

[0360] ##STR00325##

[0361] 49.0 g (0.163 mol) of 1-bromo-2-fluoro-4-iodobenzene and 24.7 g (0.163 mol) of 4-methoxybenzeneboronic acid are dissolved in a mixture of 325 ml of toluene, 165 ml of water and 165 ml of ethanol, and, after addition of 1.9 g (1.64 mmol) of tetrakis(triphenylphosphine)palladium and 34.9 g (0.33 mol) of sodium carbonate, the mixture is heated under reflux overnight. The org. phase is separated off, dried over sodium sulfate and evaporated. The residue is filtered through silica gel with heptane/toluene (1:1), and the crude product is recrystallised from ethanol, giving 4-bromo-3-fluoro-4-methoxybiphenyl as a colourless solid.

1.2 2-Fluoro-4-methoxy-4-propyl-[1,1;4,1]terphenyl

[0362] ##STR00326##

[0363] 28.0 g (99.0 mmol) of 4-bromo-3-fluoro-4-methoxybiphenyl, 28.8 g (99.2 mmol) of sodium metaborate octahydrate and 1.4 g (1.96 mmol) of bis(triphenylphosphine)palladium(II) chloride are initially introduced in 75 ml of water and 100 ml of THF, 0.1 ml of hydrazine hydrate is added, and, after addition of a solution of 16.3 g (99.0 mmol) of 4-propylbenzeneboronic acid, the mixture is heated under reflux overnight. The org. phase is separated off, evaporated in vacuo, filtered through silica gel with heptane/toluene, and the crude product is recrystallised from ethanol/toluene (14:1), giving 2-fluoro-4-methoxy-4-propyl-[1,1;4,1 ]terphenyl as colourless crystals.

1.3 2-Fluoro-4-propyl-[1,1;4,1]terphenyl-4-ol

[0364] ##STR00327##

[0365] 27.2 g (85 mmol) of 2-fluoro-4-methoxy-4-propyl-[1,1;4,1 ]terphenyl are initially introduced in 400 ml of dichloromethane at 10 C., and 100 ml (100 mmol) of a 1 M solution of boron tribromide in hexane are added dropwise. The cooling is removed, and the batch is left to stir at room temp. for 3 h. The batch is subsequently hydrolysed using 200 ml of water with cooling, the precipitated product is dissolved by addition of 800 ml of warm dichloromethane, and the aqueous phase is separated off. The org. phase is washed with water and sat. sodium hydrogencarbonate soln. and dried over sodium sulfate, giving 2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-ol as a colourless solid, which is employed in the next step without further purification.

1.4 4-(2-Benzyloxyethoxy)-2-fluoro-4-propyl-[1,1;4,1]terphenyl

[0366] ##STR00328##

[0367] The crude product from step 1.4 is dissolved in 300 ml of ethyl methyl ketone, 23.9 g (173 mmol) of potassium carbonate and 20.0 g (90 mmol) of 2-benzyloxyethyl bromide are added, and the mixture is heated under reflux overnight. The batch is filtered, the filtrate is evaporated, and the residue is filtered through silica gel with toluene. Crystallisation of the crude product from ethanol/toluene (6:1) gives 4-(2-benzyloxyethoxy)-2-fluoro-4-propyl-[1,1;4,1]terphenyl as a colourless solid.

1.5 2-(2-Fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethanol

[0368] ##STR00329##

[0369] 24.5 g (56 mmol) of 4-(2-benzyloxyethoxy)-2-fluoro-4-propyl-[1,1;4,1 ]terphenyl are hydrogenated to completion on palladium/carbon in THF. The catalyst is filtered off, the filtrate is evaporated, and the crude product is recrystallised from ethanol/toluene (8:1), giving 2-(2-fluoro-4-propyl-[1,1;4,1 ]terphenyl-4-yloxy)ethanol as colourless needles.

1.6 2-(2-Fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl toluene-4-sulfonate

[0370] ##STR00330##

[0371] 7.0 g (20 mmol) of 2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethanol are dissolved in 200 ml of dichloromethane, 3.3 ml (40 mmol) of pyridine and 120 mg of DMAP are added, and the mixture is cooled to 10 C. After addition of 4.6 g (24 mmol) of tosyl chloride, the batch is stirred at room temperature overnight, and 500 ml of water are subsequently added. The aqueous phase is separated off and extracted with dichloromethane. The combined org. phases are washed with dil. hydrochloric acid and with sat. sodium hydrogencarbonate solution and dried over sodium sulfate. The solvent is removed in vacuo, and the residue is purified by chromatography on silica gel with toluene, giving 2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl toluene-4-sulfonate as a colourless solid.

1.7 N-[2-(2-Fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl]ethane-1,2-diamine

[0372] ##STR00331##

[0373] 1.00 g (1.98 mmol) of 2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)-ethyl toluene-4-sulfonate is warmed at 60 C. overnight in 20 ml of ethylenediamine. The amine is subsequently removed in vacuo, and the residue is filtered through silica gel with dichloromethane/methanol/25 percent ammonia (80:20:2), giving N-[2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl]ethane-1,2-diamine as a colourless solid.

[0374] .sup.1H-NMR (300 MHz, CDCl.sub.3)

[0375] =0.98 ppm (t, J=7.4 Hz, 3H, CH.sub.3), 1.56 (s, br., 2H, NH.sub.2), 1.69 (sext., J=7.4 Hz, 2H, CH.sub.2CH.sub.2CH.sub.3), 2.64 (t, J=7.4 Hz, 2H, CH.sub.2Et), 2.76 (t, J=5.8 Hz, 2H, CH.sub.2NH.sub.2), 2.85 (t, J=5.8 Hz, 2H, CH.sub.2CH.sub.2NH.sub.2), 3.05 (t, J=5.2 Hz, 2H, OCH.sub.2CH.sub.2), 4.13 (t, J=5.8 Hz, 2H, OCH.sub.2), 6.99 (AB-d, J=8.7 Hz, 2H, ArH), 7.26 (d, J=8.5 Hz, 2H, ArH), 7.33 (dd, J=1.7 Hz, J=12.1 Hz, 1H, ArH), 7.38 (dd, J=1.7 Hz, J=8.0 Hz, 1H, ArH), 7.50 (m.sub.c, 2 H, ArH), 7.54 (AB-d, J=8.7 Hz, 2H, ArH).

Example 2: N-[2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl]-propane-1,3-diamine

[0376] ##STR00332##

[0377] Analogously to Example 1, 2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl toluene-4-sulfonate and 1,3-diaminopropane give N-[2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl]propane-1,3-diamine.

[0378] .sup.1H-NMR (300 MHz, CDCl.sub.3)

[0379] =0.98 ppm (t, J=7.3 Hz, 3H, CH.sub.3), 1.55-1.90 (m, 6H, in which: 1.67 (quint., J=7.1 Hz, NHCH.sub.2CH.sub.2CH.sub.2NH.sub.2); s, br., NH2; CH.sub.3CH.sub.2CH.sub.2), 2.63 (dd, J=7.3 Hz, J=8.0 Hz, 2H, ArCH.sub.2Et), 2.75 (t, J=7.1 Hz, 2H, CH.sub.2NH.sub.2), 2.78 (t, J=6.9 Hz, 2H, NHCH.sub.2(CH.sub.2).sub.2NH.sub.2), 3.01 (t, J=5.3 Hz, 2H, OCH.sub.2CH.sub.2NH), 3.41 (s, 1H, NH), 4.11 (t, J=5.3 Hz, 2H, OCH.sub.2), 6.98 (AB-d, J=8.8 Hz, 2H, ArH), 7.26 (d, J=8.2 Hz, 2H, ArH), 7.32 (dd, J=1.8 Hz, J=12.2 Hz, 1H, ArH), 7.37 (dd, J=1.8 Hz, J=8.0 Hz, 1H, ArH), 7.43-7.56 (m, 5H, ArH).

Example 3: [2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl]-(2-methoxyethyl)amine

[0380] ##STR00333##

[0381] Analogously to Example 1, 2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl toluene-4-sulfonate and 2-methoxy-1-ethylamine give [2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl]-(2-methoxyethyl)amine as a colourless solid.

[0382] .sup.1H-NMR (400 MHz, CDCl.sub.3)

[0383] =0.98 ppm (t, J=7.3 Hz, 3H, CH.sub.3), 1.69 (sext., J=7.5 Hz, 2H, CH.sub.3CH.sub.2CH.sub.2), 1.74 (s, br., NH), 2.64 (dd, J=6.7 Hz, J=8.6 Hz, 2H, CH.sub.2 Et), 2.89 (t, J=5.3 Hz, 2H, CH.sub.2NH), 3.06 (t, 5.3 Hz, 2H, CH.sub.2NH), 3.38 (s, 3H, OCH.sub.3), 3.54 (dd, J=5.3, J=5.3 Hz, 2H, OCH.sub.2), 4.13 (t, 5.3 Hz, 2H, OCH.sub.2), 7.00 (AB-d, J=8.7 Hz, 2H, ArH), 7.26 (d, J=8.3 Hz, 2H, ArH), 7.32 (dd, J=1.7 Hz, J=12.2 Hz, 1H, ArH), 7.39 (dd, J=1.8 Hz, J=8.0 Hz, 1H, ArH), 7.44-7.57 (m, 5H, ArH).

Example 4: 2-fluoro-4-[2-(2-methoxyethoxy)ethoxy]-4-propyl-[1,1;4,1]terphenyl

[0384] ##STR00334##

[0385] 735 mg (18.4 mmol) of a 60 percent dispersion of sodium hydride in mineral oil are washed with pentane under nitrogen and dried in vacuo. 30 ml of THF and 1.21 g (15.9 mmol) of ethylene glycol monomethyl ether are subsequently added, and the mixture is left to stir at room temp. until the evolution of gas is complete. After addition of a solution of 5.00 g (12.2 mmol) of 2-(2-fluoro-4-propyl-[1,1;4,1]terphenyl-4-yloxy)ethyl toluene-4-sulfonate in 10 ml of THF, the batch is left to stir at room temperature for 3 d, and excess sodium hydride is then decomposed by addition of methanol. The solution is added to water, acidified using 2 M hydrochloric acid and extracted three times with MTB ether. The combined org. phases are dried over sodium sulfate and evaporated in vacuo. The crude product is filtered through silica gel with dichloromethane and recrystallised from toluene, giving 2-fluoro-4-[2-(2-methoxyethoxy)ethoxy]-4-propyl-[1,1;4,1]terphenyl as colourless crystals.

Example 5: N-{2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]-ethyl}ethane-1,2-diamine

5.1 tert-Butyl-{2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethoxy}dimethylsilane

[0386] ##STR00335##

[0387] 1.15 g (28.8 mmol) of a 60 percent suspension of sodium hydride in paraffin oil are initially introduced in 70 ml of THF, and a solution of 9.0 g (23.2 mmol) of (3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-ol in 60 ml of THF is added dropwise. The batch is heated at 70 C. for 2 h, a solution of 10 ml (49 mmol) of (2-bromoethoxy)-tert-butyldimethylsilane in 50 ml of THF is added, and the mixture is stirred at 70 C. overnight. The mixture is subsequently hydrolysed using 300 ml of water and extracted three times with MTB ether. The combined org. phases are washed with water and dried over sodium sulfate. The solvent is removed in vacuo, and the residue is chromatographed on silica gel with toluene, giving tert-butyl-{2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethoxy}dimethylsilane as colourless crystals.

5.2 2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-Dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethanol

[0388] ##STR00336##

[0389] 1.90 g (3.47 mmol) of tert-butyl-{2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethoxy}dimethylsilane are dissolved in 20 ml of THF, and 3.8 ml (38 mmol) of a 1 M solution of tetrabutylammonium fluoride in THF are added dropwise with ice cooling. The cooling is removed, the batch is left to stir at room temp. for 15 min and added to water. The aqueous phase is separated off and extracted with MTB ether. The combined org. phases are washed with sat. sodium chloride soln., dried over sodium sulfate, and the solvent is removed in vacuo, giving 2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethanol as a viscous yellow oil, which is employed in the next step without further purification.

5.3 2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-Dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethyl toluene-4-sulfonate

[0390] ##STR00337##

[0391] Analogously to Example 1, 2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethanol gives 2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethyl toluene-4-sulfonate as a viscous oil.

5.4 N-{2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-Dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethyl}-ethane-1,2-diamine

[0392] ##STR00338##

[0393] Analogously to Example 1, 2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethyl toluene-4-sulfonate gives N-{2-[(3S,5S,8R,9S,10S,13R,14S,17R)-17-((R)-1,5-dimethylhexyl)-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-3-yloxy]ethyl}ethane-1,2-diamine as a colourless viscous oil.

[0394] .sup.1H-NMR (500 MHz, CDCl.sub.3)

[0395] =0.65 (s, 3H, CH.sub.3), 0.75-0.89 (m, 46H, in which: 0.79 (s, 3H, CH.sub.3),0.86 (d, J=2.1 Hz, 3H, CH.sub.3), 0.87 (d, J=2.1 Hz, 3H, CH.sub.3), 0.90 (d, J=6.5 Hz, 3H, CH.sub.3), alkyl-H, NH, NH.sub.2), 1.96 (ddd, J=12.6 Hz, J=3.2 Hz, J=3.2 Hz, 1H), 2.69 (t, J=6.0 Hz, 2H, CH.sub.2NH.sub.2), 2.77 (dd, J=5.4 Hz, J=5.4 Hz, 2H, OCH.sub.2CH.sub.2NH), 2.81 (t, J=6.0 Hz, 2H, NHCH.sub.2CH.sub.2NH.sub.2), 3.22 (dddd, J=4.7 Hz, J=4.7 Hz, J=4.7 Hz, J=4.7 Hz, 1H, >CHO), 3.58 (m.sub.c, 2 H, CH.sub.2O).

[0396] The following compounds for use in LC media are prepared analogously or in accordance with a literature procedure (in some cases also commercially available):

TABLE-US-00007 Example No. Structural formula 6. [00339] 7. [00340] 8. [00341] 9. [00342] 10. [00343] 11. [00344] 12. [00345] 13. [00346] 14. [00347] 15. [00348] 16. [00349] 17. [00350] 18. [00351] 19. [00352] 20. [00353] 21. [00354] 22. [00355]

Mixture Examples

[0397] For the preparation of LC media according to the invention, the following liquid-crystalline mixtures consisting of low-molecular-weight components in the stated percentage proportions by weight are used.

TABLE-US-00008 TABLE 1 Nematic LC medium M1 ( < 0) CY-3-O4 14% Cl.p. +80 C. CCY-3-O2 9% n 0.090 CCY-3-O3 9% 3.3 CPY-2-O2 10% .sub. 3.4 CPY-3-O2 10% K.sub.3/K.sub.1 0.97 CCY-3-1 8% CCH-34 9% CCH-35 6% PCH-53 10% CCH-301 6% CCH-303 9%

TABLE-US-00009 TABLE 2 Nematic LC medium M2 ( > 0) CC-4-V 10% Cl.p. +77 C. CC-5-V 13.5%.sup. n 0.113 PGU-3-F 6.5% 19.2 ACQU-2-F 10% .sub. 23.8 ACQU-3-F 12% K.sub.3/K.sub.1 0.97 PUQU-3-F 11% CCP-V-1 12% APUQU-2-F 6% APUQU-3-F 7% PGUQU-3-F 8% CPGU-3-OT 4%

Mixture Example 1

[0398] The compound from Synthesis Example 5 (0.2% by weight) is added to a nematic LC medium M1 of the VA type (<0) as shown in Table 1, and the mixture is homogenised.

[0399] Use in test cells without pre-alignment layer:

[0400] The resultant mixture is introduced into a test cell (without polyimide alignment layer, layer thickness d4.0 m, ITO coating on both sides, no passivation layer). The LC medium has spontaneous homeotropic (vertical) alignment to the substrate surfaces. This alignment remains stable up to 70 C. In the temperature-stable range, the VA cell can be switched reversibly between crossed polarisers by application of a voltage of between 0 and 30 V.

Mixture Example 2

[0401] The compound from Synthesis Example 5 (0.5% by weight) is added to a nematic LC medium M2 of the VA-IPS type (>0) as shown in Table 2, and the mixture is homogenised.

[0402] Use in test cells without pre-alignment layer:

[0403] The resultant mixture is introduced into a test cell (without polyimide alignment layer, layer thickness d10 m, ITO interdigital electrodes arranged on a substrate surface, glass on the opposite substrate surface, no passivation layer). The LC medium has spontaneous homeotropic (vertical) alignment to the substrate surfaces. This alignment remains stable up to 70 C. In the temperature-stable range, the VA-IPS cell can be switched reversibly between crossed polarisers by application of a voltage of between 0 and 20 V.

Mixture Examples 3-17

[0404] The compounds of Synthesis Examples 1, 2, 3 and Examples 6-17 are added analogously to Mixture Example 1 to a nematic LC medium M1 (<0) as shown in Table 1, and the mixture is homogenised. The proportions by weight of the compounds in the medium are indicated in Table 3. The resultant LC medium is in each case introduced into a test cell without prealignment layer and has spontaneous homeotropic (vertical) alignment to the substrate surfaces. In the temperature-stable range, the VA cell can be switched reversibly between crossed polarisers by application of a voltage of between 0 and 30 V.

TABLE-US-00010 TABLE 3 Proportions by weight for doping in M1 and alignment of the resultant LC mixture at 25 C. and 70 C. Test cell of the VA type Compound Propor- Alignment at Alignment at Mixture Example tion by 25 C./ 70 C./ Example No. weight switchable switchable 3 1 0.25% homeotropic/yes homeotropic/yes 4 2 0.15% homeotropic/yes homeotropic/yes 5 3 5.0% homeotropic/yes homeotropic/yes 6 6 1.0% homeotropic/yes homeotropic/yes 7 7 1.5% homeotropic/yes homeotropic/yes 8 8 2.5% homeotropic/yes homeotropic/yes 9 9 2.5% homeotropic/yes homeotropic/yes 10 10 2.5% homeotropic/yes homeotropic/yes 11 11 2.5% homeotropic/yes homeotropic/yes 12 12 0.5% homeotropic/yes homeotropic/yes 13 13 0.5% homeotropic/yes homeotropic/yes 14 14 2.0% homeotropic/yes homeotropic/yes 15 15 0.7% homeotropic/yes homeotropic/yes 16 16 1.0% homeotropic/yes homeotropic/yes 17 17 2.0% homeotropic/yes homeotropic/yes 18 18 2.0% homeotropic/yes 19 19 2.0% homeotropic/yes 20 20 1.0% homeotropic/yes 21 21 0.7% homeotropic/yes 22 22 0.5% homeotropic/yes

Mixture Examples 22-26

[0405] The compounds of Synthesis Example 1 and Examples 6, 7, 10, 11 are added analogously to Mixture Example 2 to a nematic LC medium M2 (>0) as shown in Table 2, and the mixture is homogenised. The proportions by weight of the compounds in the medium are indicated in Table 4. The resultant LC medium is in each case introduced into a test cell without pre-alignment layer and has spontaneous homeotropic (vertical) alignment to the substrate surfaces. In the temperature-stable range, the VA-IPS cell can be switched reversibly between crossed polarisers by application of a voltage of between 0 and 20 V.

TABLE-US-00011 TABLE 4 Proportions by weight for doping in M2 and alignment of the resultant LC mixture at 25 C. and 60 C. Test cell of the VA-IPS type Mixture Compound Propor- Alignment at Alignment at Example Example tion by 25 C./ 60 C./ No. No. weight switchable switchable 22 1 0.5% homeotropic/yes homeotropic/yes 23 6 3.0% homeotropic/yes planar 24 7 1.0% homeotropic/yes homeotropic/yes 25 10 1.7% homeotropic/yes planar 26 11 2.5% homeotropic/yes planar 27 18 2.0% homeotropic/yes 28 19 2.0% homeotropic/yes 29 20 1.0% homeotropic/yes 30 21 0.7% homeotropic/yes 31 22 0.5% homeotropic/yes

Mixture Example 32 (Polymer Stabilisation of Mixture Example 6)

[0406] A polymerisable compound (RM-1, 0.5% by weight) and a self-aligning compound (6, 1.0% by weight) are added to a nematic LC medium M1 (<0) as shown in Table 1, and the mixture is homogenised.

##STR00356##

[0407] Use in test cells without pre-alignment layer:

[0408] The resultant mixture is introduced into a test cell (without polyimide alignment layer, layer thickness d4.0 m, ITO coating on both sides, no passivation layer). The LC medium has spontaneous homeotropic (vertical) alignment to the substrate surfaces. The cell is irradiated with UV light of intensity 100 mW/cm.sup.2 at 40 C. for 15 min with application of a voltage greater than the optical threshold voltage. This causes polymerisation of the monomeric, polymerisable compound. The homeotropic alignment is thus additionally stabilised, and a pretilt is established. The resultant PSA-VA cell can be switched reversibly at up to 70 C. with application of a voltage of between 0 and 30 V. The response times are shortened compared with the unpolymerised cell.

Mixture Example 33 (Polymer Stabilisation of Mixture Example 7)

[0409] A polymerisable compound (RM-1, 0.5% by weight) and a self-aligning compound (7, 1.7% by weight) are added to a nematic LC medium M1 (<0) as shown in Table 1, and the mixture is homogenised.

##STR00357##

[0410] Use in test cells without pre-alignment layer:

[0411] The resultant mixture is introduced into a test cell (without polyimide alignment layer, layer thickness d4.0 m, ITO coating on both sides, no passivation layer). The LC medium has spontaneous homeotropic (vertical) alignment to the substrate surfaces. The cell is irradiated with UV light of intensity 100 mW/cm.sup.2 at 40 C. for 15 min with application of a voltage greater than the optical threshold voltage. This causes polymerisation of the monomeric compound. The homeotropic alignment is thus additionally stabilised, and a pretilt is established. The resultant PSA-VA cell can be switched reversibly at up to 70 C. by application of a voltage of between 0 and 30 V. The response times are shortened compared with the unpolymerised cell.