Liquid-crystalline medium

Abstract

The invention relates to a liquid-crystalline medium comprising at least one compound of the formula I, ##STR00001##
in which R.sup.1 has the meanings indicated in Claim 1, and to the use thereof in liquid-crystalline media and in electro-optical liquid-crystal displays.

Claims

1. Liquid-crystalline medium, comprising: one or more compounds of the formula I, ##STR00317## in which R.sup.1 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, CHCH, ##STR00318## O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, one or more compounds selected from the group consisting of compounds of the following formulae, ##STR00319## ##STR00320## in which R.sup.3a and R.sup.4a each, independently of one another, denote H, CH.sub.3, C.sub.2H.sub.5 or C.sub.3H.sub.7, provided that for formula IIb R.sup.3a is not hydrogen, and alkyl denotes a straight-chain alkyl group having 1 to 8 C atoms, and one or more compounds selected from the group consisting of compounds of the formulae X and XI, ##STR00321## in which R.sup.0 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, CC, CF.sub.2O, CHCH, ##STR00322## O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, X.sup.0 denotes F, Cl, a mono- or polyfluorinated alkyl or alkoxy radical having 1 to 6 C atoms, or a mono- or polyfluorinated alkenyl or alkenyloxy radical having 2 to 6 C atoms, Y.sub.1-4 each, independently of one another, denote H or F, and ##STR00323## each, independently of one another, denote ##STR00324## wherein the liquid-crystalline medium has a positive dielectric anisotropy.

2. Liquid-crystalline medium according to claim 1, wherein R.sup.1 in formula I denotes a straight-chain alkyl radical, in which, in addition, one or more CH.sub.2 groups may be replaced by CHCH.

3. Liquid-crystalline medium according to claim 1, which comprises at least one compound of formula I which is from the group of the compounds of the formulae I-1 to I-5 ##STR00325##

4. Liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds selected from the compounds of the formulae IV to VIII, ##STR00326## in which R.sup.0 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, CHCH, ##STR00327## O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, X.sup.0 denotes F, Cl, a mono- or polyfluorinated alkyl or alkoxy radical having 1 to 6 C atoms, a mono- or polyfluorinated alkenyl or alkenyloxy radical having 2 to 6 C atoms, Y.sup.1-6 each, independently of one another, denote H or F, Z.sup.0 denotes C.sub.2H.sub.4, (CH.sub.2).sub.4, CHCH, CFCF, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CH.sub.2O, OCH.sub.2, COO, CF.sub.2O or OCF.sub.2, and in the formulae V and VI may also denote a single bond, and r denotes 0 or 1.

5. Liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds selected from the compounds of the formulae Va to Vj, ##STR00328## in which R.sup.0 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, CHCH, ##STR00329## O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, X.sup.0denotes F, Cl, a mono- or polyfluorinated alkyl or alkoxy radical having 1 to 6 C atoms, or a mono- or polyfluorinated alkenyl or alkenyloxy radical having 2 to 6 C atoms.

6. Liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds selected from the compounds of the formulae VI-1a to VI-1d, ##STR00330## in which R.sup.0 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, CHCH, ##STR00331## O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, X.sup.0 denotes F, Cl, a mono- or polyfluorinated alkyl or alkoxy radical having 1 to 6 C atoms, or a mono- or polyfluorinated alkenyl or alkenyloxy radical having 2 to 6 C atoms.

7. Liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds selected from the compounds of the formulae VI-2a to VI-2f, ##STR00332## in which R.sup.0 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, CHCH, ##STR00333## O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, X.sup.0 denotes F, Cl, a mono- or polyfluorinated alkyl or alkoxy radical having 1 to 6 C atoms, or a mono- or polyfluorinated alkenyl or alkenyloxy radical having 2 to 6 C atoms.

8. Liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds selected from the compounds of the formula XII, ##STR00334## in which R.sup.1 and R.sup.2 each, independently of one another, denote alkyl, alkenyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyloxy, each having up to 9 C atoms, and Y.sup.1 denotes H or F.

9. Liquid-crystalline medium according claim 1, which additionally comprises one or more compounds selected from the compounds of the formulae XIII to XVI, ##STR00335## in which R.sup.0 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, CH, ##STR00336## O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, X.sup.0 denotes F, Cl, a mono- or polyfluorinated alkyl or alkoxy radical having 1 to 6 C atoms, a mono- or polyfluorinated alkenyl or alkenyloxy radical having 2 to 6 C atoms, Y.sup.1-2 each, independently of one another, denote H or F.

10. Liquid-crystalline medium according to claim 1: which additionally comprises a compound of the formula CC-3-V; ##STR00337## or which comprises a compound of IIb or IIc which is of one of the following formulae; ##STR00338##

11. Liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds selected from the compounds of the formulae D1, D2, D3, D4 and D5, ##STR00339## in which R.sup.0 denotes an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, CHCH, ##STR00340## O, COO or OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, X.sup.0 denotes F, Cl, a mono- or polyfluorinated alkyl or alkoxy radical having 1 to 6 C atoms, a mono- or polyfluorinated alkenyl or alkenyloxy radical having 2 to 6 C atoms, Y.sup.1-2 each, independently of one another, denote H or F.

12. Liquid-crystalline medium according to claim 1, which comprises 1-30% by weight of compounds of the formula I.

13. Liquid-crystalline medium according to claim 1, which additionally comprises one or more UV stabilisers and/or antioxidants.

14. Liquid-crystalline medium according to claim 1, which additionally additionally comprises one or more polymerisable compounds.

15. Liquid-crystalline medium according to claim 14, wherein the polymerisable compound is selected from the following compounds RM-1 to RM-83: ##STR00341## ##STR00342## ##STR00343## ##STR00344## ##STR00345## ##STR00346## ##STR00347## ##STR00348## ##STR00349##

16. A process for the preparation of a liquid-crystalline medium according to claim 1, comprising mixing one or more compounds of the formula I with at least one further mesogenic compound and optionally with one or more additive(s) and/or one or more polymerisable compounds.

17. An electro-optical device comprising a liquid-crystalline medium according to claim 1.

18. An electro-optical device according to claim 17 which is a TN, STN, TN-TFT, OCB, IPS, PS-IPS, FFS or PS-FFS display, a shutter spectacle for 3D effects, an LC lens or a positive VA display.

19. Electro-optical liquid-crystal display containing a liquid-crystalline medium according to claim 1.

20. Liquid-crystalline medium according to claim 1, which additionally comprises one or more stabilizers selected from the following: ##STR00350## ##STR00351## ##STR00352## ##STR00353##

21. Liquid-crystalline medium according to claim 20, which comprises up to 10% by weight of the one or more stabilizers.

22. Liquid-crystalline medium according to claim 1, which additionally comprises a stabilizer of the following formula: ##STR00354##

23. Liquid-crystalline medium according to claim 22, which comprises up to 10% by weight of the stabilizer.

24. Liquid-crystalline medium according to claim 1, which comprises at least one compound of formula I which is of the formulae I-2: ##STR00355##

Description

EXAMPLES

(1) The following working examples are intended to explain the invention without restricting it.

(2) Above and below, percentage data denote percent by weight. All temperatures are indicated in degrees Celsius. m.p. denotes melting point, cl.p.=clearing point. Furthermore, C=crystalline state, N=nematic phase, S=smectic phase and I=isotropic phase. The data between these symbols represent the transition temperatures. Furthermore, V.sub.o denotes threshold voltage, capacitive [V] at 20 C. n denotes the optical anisotropy measured at 20 C. and 589 nm denotes the dielectric anisotropy at 20 C. and 1 kHz cp. denotes clearing point [ C.] K.sub.1 denotes elastic constant, splay deformation at 20 C., [pN] K.sub.3 denotes elastic constant, bend deformation at 20 C., [pN] .sub.1 denotes rotational viscosity measured at 20 C. [mPa.Math.s], determined by the rotation method in a magnetic field LTS denotes low-temperature stability (nematic phase), determined in test cells.

Synthesis Examples

(3) Conventional work-up means: water is added if necessary, the mixture is extracted with methylene chloride, diethyl ether, methyl tert-butyl ether or toluene, the phases are separated, the organic phase is dried and evaporated, and the product is purified by distillation under reduced pressure or crystallisation and/or chromatography.

Example 1

(4) The compound of the formula

(5) ##STR00307##
is prepared in accordance with the following scheme:

(6) ##STR00308## C 20 S.sub.B 74 N 78 I; n=0.057; =0.82; .sub.1=28 mPa.Math.s;
The following compounds

(7) ##STR00309##
are prepared analogously.

Mixture Examples

(8) The electro-optical data are measured in a TN cell at the 1st minimum (i.e. at a d.Math.n value of 0.5 m) at 20 C., unless expressly indicated otherwise. The optical data are measured at 20 C., unless expressly indicated otherwise. All physical properties are determined in accordance with Merck Liquid Crystals, Physical Properties of Liquid Crystals Status November 1997, Merck KGaA, Germany, and apply for a temperature of 20 C., unless explicitly indicated otherwise.

Example M1

(9) TABLE-US-00007 CC-3-V 10.00% Clearing point [ C.]: 100.0 CC-3-V1 12.00% n [589 nm, 20 C.] 0.1014 CC-3-2V 12.00% [kHz, 20 C.]: +8.7 CC-3-2V1 11.00% .sub.1 [mPa .Math. s, 20 C.]: 100 CCGU-3-F 6.00% K.sub.1 [20 C.]: 21.9 APUQU-2-F 7.00% K.sub.3 [20 C.]: 22.2 APUQU-3-F 12.00% V.sub.0 [V]: 1.67 CCP-30CF.sub.3 6.00% CCP-40CF.sub.3 5.00% PP-1-2V1 6.00% ECCP-30CF.sub.3 5.00% ECCP-50CF.sub.3 5.00% PGUQU-3-F 3.00%

Example M2

(10) TABLE-US-00008 CC-3-V 14.00% Clearing point [ C.]: 104.5 CC-3-V1 14.00% n [589 nm, 20 C.] 0.1019 CC-3-2V 12.00% [kHz, 20 C.]: +8.8 CC-3-2V1 12.00% .sub.1 [mPa .Math. s, 20 C.]: 108 CCGU-3-F 7.00% K.sub.1 [20 C.]: 20.6 APUQU-2-F 7.00% K.sub.3 [20 C.]: 21.2 APUQU-3-F 13.00% V.sub.0 [V]: 1.62 PP-1-2V1 3.00% ECCP-30CF.sub.3 5.00% ECCP-50CF.sub.3 5.00% PGUQU-3-F 4.00% CBC-33 4.00%

Example M3

(11) For the preparation of a PS-IPS mixture, 0.25% of compound RM-1

(12) ##STR00310##
is added to mixture M2.

Example M4

(13) TABLE-US-00009 CC-3-V 25.00% Clearing point [ C.]: 91.50 CC-3-V1 11.00% n [589 nm, 20 C.] 0.1047 CC-3-2V 11.00% [kHz, 20 C.]: +10.3 CCQU-3-F 22.50% .sub.1 [mPa .Math. s, 20 C.]: 86 PGUQU-3-F 3.00% K.sub.1 [20 C.]: 14.4 PGUQU-4-F 9.50% K.sub.3 [20 C.]: 17.1 PGUQU-5-F 5.50% V.sub.0 [V]: 1.25 CPPQU-3-F 12.50%

Example M5

(14) For the preparation of a PS-FFS mixture, 0.25% of compound RM-1

(15) ##STR00311##
is added to mixture M4.

Example M6

(16) TABLE-US-00010 CC-3-V 28.00% Clearing point [ C.]: 90.5 CC-3-2V 10.00% S .fwdarw. N transition: CCP-V-1 4.00% n [589 nm, 20 C.] 0.1205 CCP-V2-1 7.00% [kHz, 20 C.]: +16.1 PP-1-2V1 1.00% .sub.1 [mPa .Math. s, 20 C.]: 102 PGP-2-2V 3.00% K.sub.1 [20 C.]: 14.5 PUQU-3-F 9.00% K.sub.3 [20 C.]: 15.2 APUQU-3-F 10.00% V.sub.0 [V]: 1.01 PGUQU-3-F 5.00% LTS (bulk) [25 C.]: >1000 h PGUQU-4-F 5.00% PGUQU-5-F 4.00% CDUQU-3-F 7.00% DPGU-4-F 7.00%

Example M7

(17) TABLE-US-00011 CC-3-V 30.00% Clearing point [ C.]: 89.0 CC-3-V1 10.00% n [589 nm, 20 C.] 0.1098 PGP-2-2V 3.00% [kHz, 20 C.]: +19.1 APUQU-2-F 10.00% .sub.1 [mPa .Math. s, 20 C.]: 104 APUQU-3-F 9.00% K.sub.1 [20 C.]: 14.4 PGUQU-4-F 7.00% K.sub.3 [20 C.]: 14.9 DGUQU-4-F 8.00% V.sub.0 [V]: 0.92 CDUQU-3-F 10.00% DPGU-4-F 6.00% CC-3-2V 7.00%

Example M8

(18) For the preparation of a PS-FFS mixture, 0.3% of compound RM-41

(19) ##STR00312##
is added to mixture M7.

Example M9

(20) TABLE-US-00012 CC-3-V 32.00% Clearing point [ C.]: 89.5 CC-3-V1 11.00% n [589 nm, 20 C.] 0.1083 CC-3-2V 8.00% [kHz, 20 C.]: +15.4 CCP-V2-1 6.00% .sub.1 [mPa .Math. s, 20 C.]: 92 APUQU-2-F 7.00% K.sub.1 [20 C.]: 14.5 APUQU-3-F 8.00% K.sub.3 [20 C.]: 15.5 PGUQU-3-F 3.00% V.sub.0 [V]: 1.03 PGUQU-4-F 7.00% PGUQU-5-F 3.00% DPGU-4-F 7.00% DGUQU-4-F 8.00%

Example M10

(21) TABLE-US-00013 CC-3-V 27.50% Clearing point [ C.]: 85.5 CC-3-V1 11.00% n [589 nm, 20 C.] 0.1092 CC-3-2V1 7.00% [kHz, 20 C.]: +17.6 CC-3-2V 3.50% .sub.1 [mPa .Math. s, 20 C.]: 92 PGP-2-2V 1.00% K.sub.1 [20 C.]: 14.5 CCP-30CF.sub.3 6.00% K.sub.3 [20 C.]: 14.7 PUQU-3-F 4.00% V.sub.0 [V]: 0.96 APUQU-2-F 6.00% APUQU-3-F 6.50% PGUQU-3-F 3.50% PGUQU-4-F 7.00% DPGU-4-F 6.00% DGUQU-2-F 3.50% DGUQU-4-F 7.50%

Example M11

(22) For the preparation of a PS-FFS mixture, 0.2% of compound RM-61

(23) ##STR00313##
is added to mixture M10.

Example M12

(24) TABLE-US-00014 CC-3-V 27.50% Clearing point [ C.]: 85.0 CC-3-V1 8.00% n [589 nm, 20 C.] 0.1093 CC-3-2V1 10.00% [kHz, 20 C.]: +17.6 CC-3-2V 5.00% .sub.1 [mPa .Math. s, 20 C.]: 93 PGP-2-2V 1.00% K.sub.1 [20 C.]: 14.6 CCP-30CF.sub.3 4.50% K.sub.3 [20 C.]: 14.8 PUQU-3-F 4.00% V.sub.0 [V]: 0.97 APUQU-2-F 6.00% APUQU-3-F 6.00% PGUQU-3-F 3.50% PGUQU-4-F 7.00% DPGU-4-F 6.50% DGUQU-2-F 3.50% DGUQU-4-F 7.50%

Example M13

(25) For the preparation of a PS-IPS mixture, 0.25% of compound RM-17

(26) ##STR00314##
is added to mixture M12.

Example M14

(27) For the preparation of a PS-FFS mixture, 0.2% of compound RM-61

(28) ##STR00315##
is added to mixture M12.

Example M15

(29) For the preparation of a PS-FFS mixture, 0.3% of compound RM-80

(30) ##STR00316##
is added to mixture M12.

(31) The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

(32) From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

(33) The entire disclosures of all applications, patents and publications, cited herein and of corresponding German Application No. DE 10 2013 013 500.1, filed Aug. 16, 2013 are incorporated by reference herein.