LIQUID-CRYSTALLINE MEDIUM

Abstract

The present invention relates to liquid-crystalline media comprising one or more compounds of formula DFS

##STR00001##

in which the groups and parameters occurring have the meanings indicated in claim 1, to high-frequency components comprising same, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, in particular for microwave phased-array antennas. The present invention further relates to novel mesogenic compounds.

Claims

1. Liquid-crystal medium, characterised in that it comprises one or more compounds of formula DFS ##STR00369## wherein L.sup.02 denotes R.sup.02 or X.sup.02, R.sup.01 and R.sup.02 denote alkyl, which is straight chain or branched having 1 to 20 C-atoms, is unsubstituted, mono- or poly-substituted by F, Cl or CN, and in which one or more CH.sub.2 groups are optionally replaced, in each case independently from one another, by O, S, SiR.sup.aR.sup.b, CO, COO, OCO, OCOO, SCO, COS, CY.sup.01CY.sup.02 or CC in such a way that O and/or S atoms are not linked directly to one another, Y.sup.01 and Y.sup.02 identically or differently, denote H, F, Cl, or CN, alternatively one of Y.sup.01 and Y.sup.02 may also denote H, R.sup.a and R.sup.b identically or differently, denote alkyl having 1 to 6 C atoms, X.sup.02 denotes H, F, Cl, CN, NCS, SF.sub.5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated or fluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms, Z.sup.01 and Z.sup.04 on each occurrence, identically or differently, denote CC, CFCF, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, or a single bond, ##STR00370## independently of one another, denote ##STR00371## wherein, one or more of CH groups, preferably one CH group or two CH groups, preferably non-adjacent, particularly preferably one CH group, may be replaced by N, and, ##STR00372## on each occurrence, independently of one another, are defined as A.sup.02 and A.sup.03, or alternatively denote ##STR00373## L.sup.0 denotes halogen, alkyl, alkenyl or alkoxy having up to 6 C atoms, cycloalkyl or cycloalkenyl having 3 to 6 C atoms, where one or more H atoms can be substituted by fluorine, r1 is an integer from 0 to 4, r2 is an integer from 0 to 6, d1 and d2 are, independently from one another, 0, 1 or 2.

2. Liquid crystal medium according to claim 1 wherein one or more compounds of formula DFS are selected from the compounds of formula DFS-1 ##STR00374## in which the groups and parameters occurring have the meanings indicated in claim 1.

3. Liquid crystal medium according to claim 1 wherein the total concentration of the compounds of formula DFS-1 is 4% or more by weight.

4. Liquid crystal medium according to claim 1 wherein one or more compounds of formula DFS are selected from the compounds of formula DFS-2 ##STR00375## in which the groups and parameters occurring have the meanings indicated in claim 1.

5. Liquid crystal medium according to claim 1 where the total concentration of compounds of formula DFS-2 is 70% by weight or less.

6. (canceled)

7. Liquid crystal medium according to claim 1, characterised in that it comprises one or more compounds of formula T ##STR00376## wherein R.sup.03 and R.sup.04 independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17, preferably 3 to 10, C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C atoms, preferably alkyl or unfluorinated alkenyl, and in case r is 0, R.sup.04 may also denote F, Cl, CN, SCN, CF.sub.3, OCF.sub.3, or SF.sub.5, ##STR00377## independently of one another, denote ##STR00378## wherein Y denotes S or O, and wherein in the 1,4-phenylene groups, one or more CH groups may be replaced by N, and L.sup.0 on each occurrence, independently of one another, denotes H, Br, Cl, F, CN, NCS, SCN, SF.sub.5, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.3-C.sub.6 cycloalkyl or a mono- or polyfluorinated C.sub.1-C.sub.10 alkyl or alkoxy group, R.sup.05 and R.sup.06 each, independently of one another, denote a halogenated or unsubstituted alkyl or alkoxy radical having 1 to 6 C atoms, r is 0 or 1.

8. Liquid-crystal medium according to claim 1, characterised in that it comprises one or more compounds of formula I ##STR00379## wherein ##STR00380## denotes ##STR00381## L.sup.11 denotes H, alkyl having 1 to 6 C atoms, cycloalkyl having 3 to 6 C atoms or cycloalkenyl having 4 to 6 C atoms, X.sup.11 denotes H, alkyl having 1 to 3 C atoms or halogen, R.sup.11 to R.sup.14, independently of one another, denote unfluorinated alkyl or unfluorinated alkoxy, each having 1 to 15 C atoms, unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl, each having 2 to 15 C atoms, or cycloalkyl, alkylcycloalkyl, cycloalkenyl, alkylcycloalkenyl, alkylcycloalkylalkyl or alkylcycloalkenylalkyl, each having up to 15 C atoms, and alternatively one of R.sup.13 and R.sup.14 or both also denote H.

9. Process for the preparation of a liquid-crystal medium according to claim 1, characterised in that one or more compounds of formula DFS of claim 1 are mixed one another and optionally with one or more further compounds and/or with one or more additives.

10. (canceled)

11. Component for high-frequency technology, characterised in that it contains a liquid-crystal medium according to claim 1.

12. Microwave antenna array, characterised in that it comprises one or more components for high-frequency technology according to claim 11.

13. Process for tuning a microwave antenna array, characterised in that a component for high-frequency technology according to claim 11 is electrically addressed.

14. A compound of formula DFS-2 ##STR00382## wherein X.sup.02 denotes NCS, ##STR00383## denotes ##STR00384## d2 is 0, and the other groups and parameters occurring have the meaning as indicated in claim 1.

15. A method of forming liquid crystalline medium, which comprises incorporating a compound of claim 14 into said medium.

16. Process for the preparation of a compound of formula DFS-2, characterised in that a compound of formula DFS-2A ##STR00385## is converted into a compound of formula DFS-2.

17. Liquid crystal medium of claim 1, which comprises one or more compounds of formula DFS-1 ##STR00386## and one or more compounds of formula DFS-2 ##STR00387##

18. Liquid crystal medium according to claim 17 where the total concentration of compounds selected from the group of compounds of formulae DFS-1 and DFS-2 is 4% or more.

Description

EXAMPLES

[0463] The following examples illustrate the present invention without limiting it in any way. However, it becomes clear to the person skilled in the art from the physical properties what properties can be achieved and in what ranges they can be modified. In particular, the combination of the various properties which can preferably be achieved is thus well defined for the person skilled in the art.

SYNTHESIS EXAMPLES

Synthesis Example 1: 5-[(E)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-1,3-difluoro-2-isothiocyanato-benzene

1.1 [(Z)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-triethyl-silane

[0464] ##STR00360##

[0465] A solution of n-BuLi in hexane (19.1 mL, 15%, 30.4 mmol) are added dropwise to a stirred solution of 4-Bromo-n-pentylbenzene (6.7 g, 29.5 mmol) in THF (65 mL) at 70 C. The resulting mixture is stirred for 1.5 h before it is treated with a solution of triethylsilyl-trifluroethylene (6.4 g, 31.6 mmol) in THF (10 mL) at the same temperature. The reaction mixture is allowed to warm to room temperature and stirred overnight, before it is quenched with sat. NH.sub.4Cl solution and diluted with methyl tert-butyl-ether. The aqueous phase is separated and extracted with methyl tert-butyl ether. The combined organic phase are washed with sat. NaCl solution, dried over Na.sub.2SO.sub.4, filtered and concentrated under vacuo. The residue is filtered through a short pad of silica (heptane) to give [(Z)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-triethyl-silane as a colourless oil.

1.2 1-[(E)-1,2-difluorovinyl]-4-pentyl-benzene

[0466] ##STR00361##

[0467] A solution of tetrabutylammonium fluoride in THF (17.1 mL, 1M, 17.1 mmol) are added dropwise to a stirred solution of [(Z)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-triethyl-silane (6.2 g, 15.5 mmol) in THF (40 mL) and water (0.28 mL, 15.5 mmol) at room temperature. The resulting mixture is stirred for 3 h at the same temperature before it is treated with water and methyl tert-butyl ether. The aqueous phase is separated and extracted with methyl tert-butyl ether. The combined organic phase are washed with sat. NaCl solution, dried over Na.sub.2SO.sub.4, filtered and concentrated under vacuo. The residue is filtered through a pad of silica (pentane) to give 1-[(E)-1,2-difluorovinyl]-4-pentyl-benzene as a colourless oil.

1.3 1-[(E)-1,2-difluoro-2-iodovinyl]-4-pentyl-benzene

[0468] ##STR00362##

[0469] A solution of n-BuLi in hexane (13.8 mL, 15%, 22.1 mmol) is added dropwise to a stirred solution of 1-[(E)-1,2-difluorovinyl]-4-pentyl-benzene (6.4 g, 66%, 20.1 mmol) in THF (12 mL) at 70 C. The resulting mixture is stirred 1 h at the same temperature, before it is treated with a solution of iodine (6.1 g, 24.1 mmol) in 15 mL THF. The reaction mixture is allowed to warm to 0 C., treated with water, methyl tert-butyl ether and sodium thiosulfate (2.2 g, 8.8 mmol). The aqueous phase is separated and extracted with methyl tert-butyl ether. The combined organic phases are washed with sat. NaCl solution, dried over Na.sub.2SO.sub.4, filtered and concentrated under vacuo. The residue is filtered through a pad of silica (pentane) to give 1-[(E)-1,2-difluoro-2-iodovinyl]-4-pentyl-benzene as a red oil.

1.4 4-[(E)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-2,6-difluoro-aniline

[0470] ##STR00363##

[0471] To a premixed suspension of sodium orthosilicate (1.8 g, 9.83 mmol) in water (4.8 mL) and PdCl.sub.2[P(Cy).sub.3].sub.2 (0.23 g, 0.31 mmol) THF (16 mL) is added, followed by 2,6-difluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (3.8 g, 14.9 mmol) and 1-[(E)-1,2-difluoro-2-iodovinyl]-4-pentyl-benzene (7.2 g, 14.9 mmol, GC: 69.6%) at room temperature. The resulting mixture is stirred overnight at 65 C., before the organic phase is separated and extracted with water. The aqueous phases are combined and extracted with methyl tert-butylether. The combined organic phase are washed with water, dried over Na.sub.2SO.sub.4, filtered and concentrated in vacuo. The residue is filtered through a pad of silica (heptane/toluene 1:1) to give 4-[(E)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-2,6-difluoro-aniline as an orange solid.

1.5 5-[(E)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-1,3-difluoro-2-isothiocyanato-benzene

[0472] ##STR00364##

[0473] Thiophosgene (1.7 mL, 21.5 mmol) is added dropwise to a stirred suspension of 4-[(E)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-2,6-difluoro-aniline (3.7g, 10.7 mmol), pyridine (0.09 mL, 1.08 mmol) and aqueous NaHCO.sub.3 (51.6g, 8.8%, 53.8 mmol) in ethyl acetate (25 mL) at 0 C. The mixture is allowed to warm to room temperature and stirred for 1 h. Additional 20 mL of sat. NaHCO.sub.3 are added followed by 1 h stirring at ambient temperature before the organic phase is separated. The aqueous phase is extracted with ethyl acetate. The combined organic phases are concentrated in vacuo, and the residue is filtered through a pad of silica (heptane/toluene 1:1), followed by crystallization from heptane (2 times) to give 5-[(E)-1,2-difluoro-2-(4-pentylphenyl)vinyl]-1,3-difluoro-2-isothiocyanato-benzene as colourless needles.

[0474] .sup.1H NMR: 0.91-0.94 (m, 3H), 1.31-1.43 (m, 4H), 1.64-1.71 (m, 2H), 2.66-2.70 (m, 2H), 7.31 (d, J=8.2 Hz, 2H), 7.37-7.42 (m, 2H), 7.71-7.65 (m, 2H); .sup.19F NMR: 154.4 (dt, J=119.4, 3.7 Hz, 1F),145.4 (d, J=119.1 Hz, 1F),116.8 (dt, J=9.2, 2.8 Hz, 2F); EI-MS: 379.1.

[0475] Phase sequence: K 64 SmA 102 N 113.5 I

[0476] In Analogy to Synthesis Example 1, the Synthesis Examples 2, 3 and 4 are prepared:

Synthesis Example 2

[0477] ##STR00365##

[0478] Phase sequence: K 75 SmA 95 N 112.3 I

[0479] =16.2

[0480] n=0.3986

[0481] .sub.1=64 mPa s

Synthesis Example 3

[0482] ##STR00366##

[0483] Phase sequence: K 47 N 57 I

[0484] =19.7

[0485] n=0.3035

[0486] .sub.1=77 mPa s

Synthesis Example 4

[0487] ##STR00367##

[0488] Phase sequence: K 75 SmX 234 N 274.4 I

[0489] In analogy to the above described synthesis and starting from 1-(4-n-pentylphenylethynyl)-2-ethyl-4-(Z-1,2-difluoro-2-iodoethylenyl)-benzene, prepared according to the procedure described on page 33 of WO 2012/069133 A1, Synthesis Example 4 is prepared.

Synthesis Example 5

[0490] ##STR00368##

[0491] Phase sequence: K 120 N 196.9 I

[0492] n=0,5312

[0493] .sub.1=1983 mPa s

[0494] Use Examples

Comparative Example C-1

[0495] A liquid-crystalline substance having the abbreviation PTP(2)TP-6-3 is prepared by the method of Hsu, C. S., Shyu, K. F., Chuang, Y. Y. and Wu, S.-T., Liq. Cryst., 27 (2), (2000), pp. 283-287, and investigated with respect to its physical properties, in particular in the microwave region. The compound has a nematic phase and a clearing point (T(N,I)) of 119 C. and a melting point of 14 C. Further physical properties at 20 C. are: n.sub.e(589.3 nm)=1.8563; n(589.3 nm)=0.3250; .sub.(1 kHz)=3.4; (1 kHz)=0.8 and .sub.1=1708 mPa.Math.s. The compound is suitable for applications in the microwave region and/or millimetre wave region, in particular for phase shifters but lacks low temperature stability due to its high melting point of 14 C.

TABLE-US-00006 TABLE 1a Properties of the compound PTP(2)TP-6-3 at 30 GHz T/ C. .sub.r, .sub.r, tan .sub., r, tan .sub., r, 20 3.22 2.44 0.242 0.0029 0.0064 37.9

TABLE-US-00007 TABLE 1b Properties of the compound PTP(2)TP-6-3 at 19 GHz T/ C. .sub.r, .sub.r, tan .sub., r, tan .sub., r, 20 3.35 2.42 0.278 0.0029 0.0061 45.2

[0496] In addition, the properties of the compound n-1-pentyl-4-cyanobiphenyl (also called PP-5-N or CB15) (Comparative Example C-2) and the liquid-crystal mixture ZLI-4792 (product from Merck KGaA, Darmstadt, Germany, Comparative Example C-3) were investigated at 19 GHz.

[0497] Mixture Examples 1 to 30 are prepared according to the tables given below. All Mixture Examples have broad nematic phase ranges with the clearing temperatures (T(N,I)) given in the respective table and good low temperature stability suitable for applications in microwave devices.

[0498] Use Example 1

TABLE-US-00008 PVfP-2-4 100% T.sub.(N,I) [ C.]: 50.5 .sub.||: 2.9 : 0.5 .sub.1 [mPa .Math. s]: 41 K.sub.1 [pN]: 7.0 K.sub.3 [pN]: 9.3 V.sub.0 [V]: 3.92

[0499] Mixture Example 2

TABLE-US-00009 PVfP-2-2 67.0% T.sub.(N, I) [ C.]: 97.0 PVfGP-2-4 33.0% .sub.: 3.3 : 0.6 .sub.1 [mPa .Math. s]: 93 K.sub.1 [pN]: 13.1 K.sub.3 [pN]: 19.3 V.sub.0 [V]: 5.10

[0500] Mixture Example 3

TABLE-US-00010 PVfP-2-4 60.0% T.sub.(N, I) [ C.]: 86.0 NpVfP-4-6 10.0% .sub.: 3.1 NpVfP-4-4 30.0% : 0.6 .sub.1 [mPa .Math. s]: 98 K.sub.1 [pN]: 11.5 K.sub.3 [pN]: 15.9 V.sub.0 [V]: 4.53

[0501] Mixture Example 4

TABLE-US-00011 PVfP-2-4 70.0% T.sub.(N, I) [ C.]: 66.0 PTPI(2)VfU-6-F 20.0% .sub.: 6.8 PTPI(2)VfU-5-F 10.0% : 4.0 .sub.1 [mPa .Math. s]: 86 K.sub.1 [pN]: 9.3 K.sub.3 [pN]: 10.8 V.sub.0 [V]: 1.62

[0502] Mixture Example 5

TABLE-US-00012 PVfP-2-4 85.0% T.sub.(N, I) [ C.]: 52.0 PVfUQU-3-F 15.0% .sub.: 6.6 : 3.7 .sub.1 [mPa .Math. s]: 40 K.sub.1 [pN]: 7.2 K.sub.3 [pN]: 8.2 V.sub.0 [V]: 1.47

[0503] Mixture Example 6

TABLE-US-00013 CC-3-V 20.0% T.sub.(N, I) [ C.]: 126 PVfP(2)TP-4-4 16.0% n.sub.o: 1.5077 PVfP(2)TP-3-6 20.0% n: 0.3091 PVfP(2)TP-3-4 20.0% .sub.: 5.8 PTPI(2)VfG-6-OT 12.0% : 3.0 PTPI(2)VfG-5-OT 12.0% .sub.1 [mPa .Math. s]: 567 K.sub.1 [pN]: 13.3 K.sub.3 [pN]: 24.4 V.sub.0 [V]: 2.23

[0504] Mixture Example 7

TABLE-US-00014 PTPI(2)VfG-6-OT 20.0% T.sub.(N, I) [ C.]: 117 PTPI(2)VfG-5-OT 20.0% .sub.: 7.6 PTP(2)TP-6-3 60.0% : 4.5 .sub.1 [mPa .Math. s]: 1560 K.sub.1 [pN]: 13.3 K.sub.3 [pN]: 24.3 V.sub.0 [V]: 1.82

[0505] Mixture Example 8

TABLE-US-00015 PTG(c3)TP-4-4 40.0% T.sub.(N, I) [ C.]: 115 PTNp-4-5 20.0% .sub.: 3.6 NpVfP-4-6 10.0% : 1.0 NpVfP-4-4 20.0% .sub.1 [mPa .Math. s]: 855 PTPI(1)-4-A1 10.0% K.sub.1 [pN]: 12.1 K.sub.3 [pN]: 29.2 V.sub.0 [V]: 3.70

[0506] Mixture Example 9

TABLE-US-00016 PTG(c3)TP-4-4 30.0% PTPI(2)GU-4-F 22.0% PTPI(2)GG-5-OT 8.0% PTNp-4-5 10.0% NpVfP-4-6 10.0% NpVfP-4-4 20.0%

[0507] Mixture Example 10

TABLE-US-00017 PTiNpTP-4-4 10.0% PTiNpTP-6-6 10.0% PTiNpTP-3-6 10.0% PTPI(2)GU-4-F 22.0% PTPI(2)GG-5-OT 8.0% PTNp-4-5 10.0% NpVfP-4-6 10.0% NpVfP-4-4 20.0%

[0508] Mixture Example 11

TABLE-US-00018 PTG(c4)TP-4-4 10.0% T.sub.(N, I) [ C.]: 105 PTPI(c3)TP-4-4 5.0% .sub.: 5.7 PTP(c3)TP-3-6 15.0% : 2.8 PTG(e5)TP-4-4 15.0% .sub.1 [mPa .Math. s]: 4809 PTiNpTPI(2)-4-4 10.0% K.sub.1 [pN]: 8.6 PTiNpTPI(2)-4-A4 5.0% K.sub.3 [pN]: 23.8 PTiNpVfP-4-4 15.0% V.sub.0 [V]: 1.85 PTiNpTP-4-OT 5.0% PTPI(2)VfU-6-F 15.0% PTiNpTP-3-F 5.0%

[0509] Mixture Example 12

TABLE-US-00019 PVfP-2-4 30.0% T.sub.(N, I) [ C.]: 92 PPTUI-3-2 20.0% n.sub.o: 1.5281 PTP-2-01 8.0% n: 0.2702 PTP-3-01 8.0% .sub.: 8.3 PGP-2-2V 20.0% : 4.7 PGUQU-3-F 4.0% K.sub.1 [pN]: 11.8 PGUQU-5-F 5.0% K.sub.3 [pN]: 13.6 PPGUQU-4-F 5.0% V.sub.0 [V]: 1.67

[0510] Mixture Example 13

TABLE-US-00020 PTG(c3)TP-4-4 80.0% T.sub.(N, I) [ C.]: 135 NpVfP-4-6 10.0% .sub.: 3.8 NpVfP-4-4 10.0% : 1.1 .sub.1 [mPa .Math. s]: 1487 K.sub.1 [pN]: 11.7 K.sub.3 [pN]: 38.2 V.sub.0 [V]: 3.46

[0511] Mixture Example 14

TABLE-US-00021 PTP(2)TP-6-3 80.0% T.sub.(N, I) [ C.]: 122 PTiNpVfP-3-4 20.0% .sub.: 3.6 : 1.0 K.sub.1 [pN]: 11.5 K.sub.3 [pN]: 43.4 V.sub.0 [V]: 3.65

[0512] Mixture Example 15

TABLE-US-00022 PPTUI-3-4 20.0% T.sub.(N, I) [ C.]: 129.5 PPTUI-4-4 20.0% .sub.: 7.3 GGP-5-CL 20.0% : 4.2 PTP(2)TP-6-3 30.0% .sub.1 [mPa .Math. s]: 1102 PTPI(2)VfU-F 10.0%

[0513] Mixture Example 16

TABLE-US-00023 PTP-3-A1 8.0% T.sub.(N, I) [ C.]: 81 PTP-5-A1 5.0% n.sub.o: 1.5465 PTPI(1)-4-A1 20.0% .sub.: 5.8 PTNp-4-5 20.0% : 3.0 PTP(1.1)-4-A1 7.0% .sub.1 [mPa .Math. s]: 883 PTP-3-A5 5.0% K.sub.1 [pN]: 11.0 PTiNpTP-3-F 10.0% K.sub.3 [pN]: 18.8 PTPTiNp-4-F 5.0% V.sub.0 [V]: 2.03 PTiNpVfU-4-F 5.0% PTiNpTU(2)-4-F 5.0% PTiNpTP-4-OT 10.0%

[0514] Mixture Example 17

TABLE-US-00024 PTP-2-O1 8.0% T.sub.(N, I) [ C.]: 85 PTP-3-O1 10.0% n.sub.o: 1.5222 PTP-5-O1 14.0% n: 0.3125 PTP-4-O2 10.0% .sub.: 7.4 PTP-2O-F 6.0% : 3.8 PTP-4O-F 8.0% .sub.1 [mPa .Math. s]: 352 PTP-6O-F 8.0% K.sub.1 [pN]: 11.0 PGUQU-3-F 4.0% K.sub.3 [pN]: 18.8 PGUQU-5-F 4.0% V.sub.0 [V]: 2.03 PTP(1)TP-4-4 6.0% PTP(1F)TP-4-4 10.0% PTPI(2)VfP-4-4 12.0%

[0515] Mixture Example M-18

TABLE-US-00025 PVfP-3-F 20.0% T.sub.(N, I) [ C.]: 100 PVfP-2-4 20.0% .sub.: 8.4 PTPI(2)VfP-4-4 30.0% : 5.5 PTPI(2)VfU-6-F 20.0% .sub.1 [mPa .Math. s]: 248 PTPI(2)VfU-5-F 10.0% K.sub.1 [pN]: 12.8 K.sub.3 [pN]: 18.7 V.sub.0 [V]: 1.61

[0516] Mixture Example M-19

TABLE-US-00026 PBP-3-OT 16.0% T.sub.(N, I) [ C.]: 68 PBP-2-4 16.0% PBPTPI(2)-3-6 24.0% PTPI(2)BU-6-F 16.0% PTPI(2)BU-5-F 8.0% PTP-2-2V 20.0%

[0517] Mixture Example M-20

TABLE-US-00027 PVfP-3-F 20.0% T.sub.(N, I) [ C.]: 91 PVfP-2-4 30.0% P(2)TPVfP-6-3 20.0% PTPI(2)VfU-6-F 20.0% PTPI(2)VfU-5-F 10.0%

[0518] Mixture Example M-21

TABLE-US-00028 PVfU-3-F 20.0% PVfP-2-4 30.0% P(2)TPVfP-6-3 20.0% PTPI(2)VfU-6-F 20.0% PTPI(2)VfU-5-F 10.0%

[0519] Mixture Example M-22

TABLE-US-00029 PVfP-3-F 20.0% T.sub.(N, I) [ C.]: 127 PVfP-2-4 20.0% .sub.: 4.2 P(2)TPVfP-6-3 30.0% : 1.7 PVfP(2)TP-3-4 20.0% .sub.1 [mPa .Math. s]: 292 PVfPP(2)TP-3-4 10.0% K.sub.1 [pN]: 15.3 K.sub.3 [pN]: 28.8 V.sub.0 [V]: 3.19

[0520] Mixture Example M-23

TABLE-US-00030 PVfP-3-F 20.0% T.sub.(N, I) [ C.]: 114 PVfP-2-4 30.0% .sub.: 4.2 P(2)TPVfP-6-3 20.0% : 1.6 PVfP(2)TP-3-4 30.0% .sub.1 [mPa .Math. s]: 309 K.sub.1 [pN]: 13.8 K.sub.3 [pN]: 26.2 V.sub.0 [V]: 3.10

[0521] Mixture Example M-24

TABLE-US-00031 P(2)TPVfP-6-3 20.0% PTPI(2)VfU-6-F 10.0% PTPI(2)VfU-5-F 10.0% PTPI(2)VfP-4-4 10.0% PTP(2)VfP-3-6 20.0% PVfP(CI)TP-6-4 20.0% PVfP(2)TP-3-4 10.0%

[0522] Mixture Example M-25

TABLE-US-00032 PVfP-3-F 20.0% T.sub.(N, I) [ C.]: 115.5 PVfP-2-4 30.0% .sub.: 4.1 P(2)TPVfP-6-3 20.0% : 1.6 PTPI(2)VfP-4-4 20.0% .sub.1 [mPa .Math. s]: 226 P(2)TNpVfP-4-4 10.0% K.sub.1 [pN]: 13.3 K.sub.3 [pN]: 22.6 V.sub.0 [V]: 3.06

[0523] Mixture Example M-26

TABLE-US-00033 PVfP-3-F 20.0% T.sub.(N, I) [ C.]: 112.5 PVfP-2-4 30.0% .sub.: 4.2 PTPI(2)VfP-4-4 20.0% : 1.7 PTP(2)VfP-3-6 30.0% .sub.1 [mPa .Math. s]: 225 K.sub.1 [pN]: 15.0 K.sub.3 [pN]: 26.1 V.sub.0 [V]: 3.17

[0524] Mixture Example M-27

TABLE-US-00034 PVfP-3-F 20.0% T.sub.(N, I) [ C.]: 110.5 PVfP-2-4 30.0% .sub.: 4.1 PTPI(2)VfP-4-4 50.0% : 1.6 .sub.1 [mPa .Math. s]: 197 K.sub.1 [pN]: 12.9 K.sub.3 [pN]: 23.0 V.sub.0 [V]: 3.00

[0525] Mixture Example M-28

TABLE-US-00035 PVfP-3-F 20.0% T.sub.(N, I) [ C.]: 124 PVfP-2-4 30.0% .sub.: 4.1 P(2)TPVfP-6-3 20.0% : 1.6 PTPI(2)VfP-4-4 20.0% .sub.1 [mPa .Math. s]: 297 PVfPP(2)TP-3-4 10.0% K.sub.1 [pN]: 14.7 K.sub.3 [pN]: 25.6 V.sub.0 [V]: 3.17

[0526] Mixture Example M-29

TABLE-US-00036 PTP-2-O1 10.0% T.sub.(N, I) [ C.]: 91 PTP-3-O1 10.0% .sub.: 9.0 PGP-2-3 6.0% : 5.2 PGP-2-4 6.0% .sub.1 [mPa .Math. s]: 396 PGP-2-5 6.0% PTP-2O-F 8.0% PTP-4O-F 8.0% PTP-6O-F 8.0% PGUQU-3-F 6.0% PGUQU-5-F 6.0% GTP(2)TP-4-4 6.0% PTP(M)TP-4-4 10.0% PTPI(2)BP-4-4 10.0%

[0527] Mixture Example M-30

TABLE-US-00037 PTP(2)TP-6-3 70.0% T.sub.(N, I) [ C.]: 119 10*P-EH 10.0% .sub.: 3.6 PTPI(c3)TP-4-4 10.0% : 0.9 PTiNpBP-3-4 10.0% K.sub.1 [pN]: 10.9 K.sub.3 [pN]: 46.4 V.sub.0 [V]: 3.17

[0528] In the following table 1, the application-relevant properties of the comparative mixtures C-1 to C-3, measured at 20 C. and 19 GHz are summarised.

TABLE-US-00038 TABLE 1 Example .sub.r, .sub.r, tan .sub. r, Max. C-1 3.35 2.42 0.278 0.0061 45.2 C-2 3.06 2.66 0.131 0.0273 4.8 C-3 2.57 2.29 0.107 0.0126 8.5

[0529] In the following table 2, the application-relevant properties of mixtures according to the invention, measured at 20 C. and 19 GHz, are summarised.

TABLE-US-00039 TABLE 2 Example .sub.r, .sub.r, tan .sub. r, tan .sub. r, 1 2.86 2.33 0.0030 0.0054 0.185 34.6 2 3.00 2.32 0.0033 0.0087 0.226 25.9 3 2.98 2.34 0.0025 0.0050 0.216 43.0 4 2.95 2.32 0.0031 0.0060 0.215 35.8 5 2.87 2.32 0.0042 0.0089 0.189 21.2 6 3.03 2.31 0.0025 0.0068 0.237 34.7 7 3.31 2.38 0.0032 0.0078 0.280 35.9 8 3.29 2.43 0.0026 0.0062 0.261 42.3 13 3.34 2.43 0.0027 0.0068 0.273 40.0 16 3.37 2.48 0.0027 0.0057 0.264 46.7 18 3.11 2.31 0.0028 0.0065 0.256 39.4 19 3.01 2.33 0.0041 0.0079 0.225 28.5 20 3.09 2.35 0.0030 0.0066 0.240 36.4 21 3.05 2.33 0.0038 0.0086 0.236 27.4 22 3.15 2.34 0.0022 0.0062 0.258 41.6 23 3.14 2.35 0.0026 0.0065 0.253 38.9 24 3.29 2.35 0.0020 0.0059 0.287 48.6

[0530] In the following table 3, the application-relevant properties of mixtures according to the invention, measured at 20 C. and 30 GHz, are summarised.

TABLE-US-00040 TABLE 3 Example .sub.r, .sub.r, tan .sub.r, tan .sub.r, 14 3.15 2.40 0.0017 0.0058 0.238 41.1 15 3.07 2.36 0.0027 0.0110 0.232 21.2 17 3.81 3.13 0.0084 0.0204 0.179 8.8 29 3.80 3.12 0.0078 0.0178 0.178 9.9 30 3.13 2.40 0.0015 0.0052 0.233 44.9

[0531] As can be seen from the data in tables 2 and 3, the liquid crystalline media of Mixture Examples 1 to 30 are very well suitable for microwave applications, especially for phase shifters for phased array antennae, because of their low dielectric loss (tan .sub.r), high tunability () and high figures-of-merit ().

[0532] The comparison with the mixtures from the state of the art (table 1) shows that by using one or more compounds of formula DFS in mixtures, higher figures-of-merit and/or higher tunability and/or lower dielectric loss can be achieved while the mixtures at the same time have very broad nematic phase ranges, high clearing temperatures and very good low temperature stabilities.