LIQUID-CRYSTALLINE MEDIUM

Abstract

The invention relates to a liquid-crystalline medium which comprises one or more compounds of the formula BO

##STR00001##

in which the parameters have the meanings indicated in Claim 1, to the use of the liquid-crystalline medium for electro-optical purposes, in particular in liquid-crystal light valves for lighting devices for motor vehicles, and to liquid-crystal light valves which comprise this medium and lighting devices for motor vehicles which contain such liquid-crystal light valves and to compounds of the formula BO.

Claims

1. Liquid-crystalline medium, characterised in that it comprises one or more compounds of the formula BO ##STR00154## in which the individual radicals have the following meanings: R.sup.01 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by F, Cl or CN and, in addition, one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00155## CC, O, COO or OCO in such a way that O atoms are not linked directly to one another, R.sup.02 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by Cl or CN and one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00156## CC, CHCH, O, COO or OCO in such a way that 0 atoms are not linked directly to one another, A.sup.1, A.sup.2, independently of one another, denote 1,4-cyclohexanediyl, in which one or two CH.sub.2 groups may be replaced by O in such a way that O atoms are not linked to one another, Z.sup.1 denotes CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, C(O)O, OC(O), trans-CHCH, trans-CFCF, CH.sub.2O, OCH.sub.2 or a single bond, Y denotes F, Cl, CF.sub.3 or alkyl or alkoxy having 1 to 6 C atoms, in which one or more H atoms may be replaced by F, r denotes 0 or 1, and s denotes 0, 1, 2, 3 or 4.

2. Liquid-crystalline medium according to claim 1, characterised in that the compounds of the formula BO are selected from compounds of the sub-formulae BO-1 and BO-2 ##STR00157## in which A.sup.1 and A.sup.2 have the meanings given in claim 1 and R.sup.01, R.sup.02 denote alkyl having 2 to 5 C atoms Z.sup.1 denotes a single bond Y denotes F, and s denotes 0, 1 or 2.

3. Liquid-crystalline medium according to claim 1, characterised in that it comprises one or more compounds of the formula I ##STR00158## in which R.sup.1 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by F and, in addition, one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00159## CHCH, O, COO or OCO in such a way that 0 atoms are not linked directly to one another, ##STR00160## on each occurrence, identically or differently, denote ##STR00161## L.sup.11 and L.sup.12, independently of one another, denote H or F, X.sup.1 denotes F, Cl, CN, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical having up to 6 C atoms.

4. Liquid-crystalline medium according to claim 3, characterised in that it comprises one or more compounds selected from the group of the compounds of the formulae I-1 to I-5, ##STR00162## in which R.sup.1, X.sup.1, L.sup.11 and L.sup.12 have the meanings indicated in claim 3 and L.sup.13 and L.sup.14, independently of one another, denote H or F.

5. Medium according to claim 1, characterised in that it comprises one or more compounds of the formula II ##STR00163## in which R.sup.2 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by F and, in addition, one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00164## CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another, ##STR00165## on each occurrence, identically or differently, denote ##STR00166## L.sup.21 and L.sup.22, independently of one another, denote H or F, X.sup.2 denotes F, Cl, CN, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical having up to 6 C atoms, Z.sup.2 denotes CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, COO, trans-CHCH, trans-CFCF, CH.sub.2O or a single bond.

6. Medium according to claim 5, characterised in that the compounds of the formula II are selected from the group of the compounds of the formulae II-1 to II-14, ##STR00167## ##STR00168## in which R.sup.2 denotes n-alkyl having up to 7 C atoms, L.sup.21 and L.sup.22, independently of one another, denote H or F and X.sup.2 denotes F, Cl, halogenated alkyl or halogenated alkoxy having up to 6 C atoms.

7. Medium according to claim 1, characterised in that it comprises one or more compounds of the formula IV, ##STR00169## in which R.sup.41, R.sup.42, independently of one another, denote n-alkyl having up to 7 carbon atoms, ##STR00170## on each occurrence, independently of one another, denote ##STR00171## Z.sup.41 and Z.sup.42 on each occurrence, independently of one another, denote CH.sub.2CH.sub.2, COO, trans-CHCH, trans-CFCF, CH.sub.2O, CF.sub.2O, CC or a single bond, and p denotes 0, 1 or 2.

8. Medium according to claim 7, characterised in that the compounds of the formula IV are selected from the compounds of the formulae IV-1 to IV-13 ##STR00172## ##STR00173## in which R.sup.41 and R.sup.42, independently of one another, denote n-alkyl having 1 to 7 C atoms and L.sup.4 denotes H or F.

9. Use of the liquid-crystalline medium according to claim 1 for electro-optical purposes.

10. Use according to claim 9 in liquid-crystal light valves for lighting devices for motor vehicles or in liquid-crystal displays.

11. Electro-optical component containing a liquid-crystalline medium according to claim 1.

12. Electro-optical component according to claim 11, where the component is a liquid-crystal light valve.

13. Lighting device for motor vehicles containing a liquid-crystal light valve according to claim 12.

14. Liquid-crystal display containing a liquid-crystal light valve according to claim 12.

15. A compound of the formula BO ##STR00174## in which the individual radicals have the following meanings: R.sup.01 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by F, Cl or CN and, in addition, one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00175## CC, O, COO or OCO in such a way that O atoms are not linked directly to one another, R.sup.02 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more H atoms in these radicals may be replaced by Cl or CN and one or more CH.sub.2 groups may each be replaced, independently of one another, by ##STR00176## CC, CHCH, O, COO or OCO in such a way that O atoms are not linked directly to one another, A.sup.1, A.sup.2, independently of one another, denote, 1,4-cyclohexanediyl, in which one or two CH.sub.2 groups may be replaced by O in such a way that O atoms are not linked to one another, Z.sup.1 denotes CH.sub.2CH.sub.1, CF.sub.2CF.sub.2, C(O)O, OC(O), trans-CHCH, trans-CFCF, CH.sub.2O, OCH.sub.2 or a single bond, Y denotes F, Cl, CF.sub.3 or alkyl or alkoxy having 1 to 6 C atoms, in which one or more H atoms may be replaced by F, r denotes 0 or 1, and s denotes 0, 1, 2, 3 or 4.

16. A compound according to claim 15, where the compounds are selected from the group of the compounds of the formulae BO-1 and BO-2 ##STR00177## in which R.sup.01, R.sup.02 denote alkyl having 2 to 5 C atoms Z.sup.1 denotes a single bond Y denotes F, and s denotes 0, 1 or 2.

17. A compound according to claim 15, where the compounds are selected from the group of the compounds of the formulae BO-1a-1 to BO-2i-4 ##STR00178## ##STR00179## ##STR00180## ##STR00181## ##STR00182## ##STR00183## ##STR00184##

Description

SYNTHESIS EXAMPLES

Example 1: 4-[2-Fluoro-4-(4-propylcyclohexyl)phenyl]-1-pentylbicyclo-[2.2.2]octane

[0156] ##STR00148##

1.1 1-Fluoro-3-(4-propylcyclohexen-1-yl)benzene

[0157] ##STR00149##

[0158] 128 ml of isopropylmagnesium chloride solution (2 M in THF, 0.26 mol) are added dropwise with ice cooling to a solution of 37.4 g (0.21 mol) of 1-bromo-3-fluorobenzene in 225 ml of tetrahydrofuran (THF). The reaction mixture is subsequently stirred at room temperature for two hours, and 30.0 g (0.21 mol) of 4-propylcyclohexanone in 200 ml of THF are then added dropwise with ice cooling. The cooling bath is removed, and the batch is left to stir overnight at room temperature. The mixture is diluted with ice-water and acidified using 2 N hydrochloric acid. The aqueous phase is extracted with MTB ether, the combined organic phases are washed with sat. sodium chloride solution, dried over sodium sulfate, filtered and evaporated. The residue is dissolved in 500 ml of toluene, and 2.1 g (12 mmol) of p-toluenesulfonic acid monohydrate are added. The batch is subsequently heated under reflux for 4 h and, after cooling, washed with 30 ml of 0.5 M sodium hydroxide solution, dried over sodium sulfate, filtered and evaporated. The residue is filtered through silica gel with n-heptane and reacted further directly without further purification.

1.2 1-Fluoro-3-(4-propylcyclohexyl)benzene

[0159] ##STR00150##

[0160] A solution of 8.7 g (30.2 mmol) of 1-fluoro-3-(4-propylcyclohexen-1-yl)benzene in 30 ml of toluene is hydrogenated to completion on a palladium/activated carbon catalyst. The catalyst is filtered off, the filtrate is evaporated, and the product obtained is subsequently filtered through silica gel with n-heptane, giving 1-fluoro-3-(4-propylcyclohexyl)benzene as a colourless oil.

1.3 4-[2-Fluoro-4-(4-propylcyclohexyl)phenyl]-1-pentylbicyclo-[2.2.2]-octane

[0161] ##STR00151##

[0162] Sulfuric acid (25 ml, 95-97 percent) is initially introduced at room temperature, and a melt of 1-pentylbicyclo-[2.2.2]octan-4-ol and 1-fluoro-3-(4-propylcyclohexyl)benzene is added dropwise. After 1 h, a further 10 ml of sulfuric acid are added, and the mixture is stirred at room temperature for 3 h. The batch is subsequently warmed at 30 C. for 30 min and then poured directly onto ice. The aqueous phase is extracted with ether, the combined organic phases are washed with water, dried over sodium sulfate and evaporated. The residue is filtered through silica gel with n-heptane. The product obtained is crystallised from ethanol and filtered off with suction, giving 4-[2-fluoro-4-(4-propylcyclohexyl)phenyl]-1-pentyl-bicyclo[2.2.2]octane as a colourless solid.

[0163] .sup.1H NMR (400 MHz, CDCl.sub.3): (ppm)=0.91 (dd, J=7.1, 7.1 Hz, 3H), 0.92 (dd, J=7.1, 7.1 Hz, 3H), 0.99-1.51 (m, 23H), 1.84-1.93 (m, 10H), 2.43 (dddd, J=12.1, 12.1, 3.3, 3.3 Hz, 1H), 6.84 (dd, J=14.3, 1.8 Hz, 1H), 6.91 (dd, J=8.1, 1.9 Hz, 1H), 7.12 (dd, J=8.4, 8.4 Hz, 1H); .sup.19F NMR (376 MHz, CDCl.sub.3): (ppm)=109.1 (dd, J=14.3, 8.8 Hz); .sup.13C NMR (101 MHz, CDCl.sub.3): (ppm)=14.3, 14.6, 20.2, 22.9, 23.5, 30.3, 30.8 (3C), 31.5 (3C), 33.1, 33.6 (2C), 34.3 (2C), 34.4 (d, J=3.3 Hz), 37.2, 39.9, 41.9 43.9, 114.7 (d, J=24.2 Hz), 122.1 (d, J=2.7 Hz), 127.3 (d, J=6.5 Hz), 133.6 (d, J=11.5 Hz), 147.7 (d, J=7.9 Hz), 162.2 (d, J=247.4 Hz).

[0164] Phase sequence: C, 73 SmB 126 N, 180.7 I.

[0165] The following are obtained analogously to Example 1:

Example 2: 4-[2-Fluoro-4-(4-propylcyclohexyl)phenyl]-1-propylbicyclo-[2.2.2]octane

[0166] ##STR00152##

[0167] Phase sequence: C, 92 SmB 159 N, 179 I

Example 3: 4-[2-Fluoro-4-(4-pentylcyclohexyl)phenyl]-1-pentylbicyclo-[2.2.2]octane

[0168] ##STR00153##

[0169] Phase sequence: C, 69 SmB 173 N, 192 I

Mixture Examples

[0170]

TABLE-US-00006 Mixture Example M1 CCQU-2-F 14.00% Clearing point [ C.]: 125.4 CCQU-3-F 16.00% n [589 nm, 20 C.]: 0.0864 CCQU-5-F 10.00% [1 kHz, 20 C.]: 9.3 CCP-2F.F.F 7.00% .sub.1 [mPa .Math. s, 20 C.]: 286 CCP-3F.F.F 13.00% CCP-5F.F.F 5.00% CCP-3-1 8.00% CBC-53F 4.00% CBC-33F 3.00% CGBo-3-3 20.00%

TABLE-US-00007 Mixture Example M2 CCQU-2-F 14.00% Clearing point [ C.]: 120.2 CCQU-3-F 16.00% n [589 nm, 20 C.]: 0.0851 CCQU-5-F 14.00% [1 kHz, 20 C.]: 10.4 CCP-2F.F.F 8.00% .sub.1 [mPa .Math. s, 20 C.]: 287 CCP-3F.F.F 14.00% CCP-5F.F.F 5.00% CBC-53F 6.00% CBC-33F 3.00% CGBo-3-3 20.00%