Liquid crystal compounds

Abstract

New compounds and their mixtures enable the formation of the ferroelectric nematic liquid crystalline phase at ambient temperature. Compounds of the formula I are presented, ##STR00001##
in which the variable groups have the meanings indicated in claim 1. Liquid crystal media comprise at least one compound of the formula I.

Claims

1. A compound of the formula I, ##STR00030## in which X.sup.1 denotes CN, F, CF.sub.3, OCF.sub.3, SCN, NCS, SF.sub.5 or OCFCF.sub.2, Z.sup.1 denotes-C(O)O, L.sup.1 H or CH.sub.3, R.sup.1 denotes an alkyl radical having 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CHCH, ##STR00031## O, S, COO or OCO in such a way that O and S atoms are not linked directly to one another, and in which one or more H atoms are each optionally replaced by halogen, or denotes H.

2. A compound according to claim 1, wherein R.sup.1 denotes alkyl having 1 to 8 carbon atoms, alkoxy with 1 to 8 carbon atoms, alkenyl with 2 to 8 carbon atoms, or alkenyloxy having 2 to 8 carbon atoms.

3. A compound according to claim 1, wherein X.sup.1 denotes CN, F or CF.sub.3.

4. A compound according to claim 1, wherein R.sup.1 comprises 2 to 7 carbon atoms.

5. A compound according to claim 1 selected from compounds of the following formulae: ##STR00032## ##STR00033## ##STR00034##

6. A compound according to claim 1, wherein X.sup.1 denotes CN.

7. A compound according to claim 1, wherein R.sup.1 denotes a straight-chain alkyl radical having 1 to 7 C atoms or an unbranched alkenyl radical having 2 to 8 C atoms.

8. A compound according to claim 1, wherein R.sup.1 is a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, in which one or more CH.sub.2 groups may be replaced, in each case independently of one another, by CC or CHCH.

9. A compound according to claim 1 selected from compounds of the following formula: ##STR00035## wherein R.sup.1 is as defined in claim 1.

10. A liquid crystal medium comprising at least one compound of the formula I according to claim 1, wherein the medium is a ferroelectric nematic liquid crystal medium.

11. A liquid crystal medium comprising at least one compound of the formula I according to claim 1.

12. A liquid crystal medium according to claim 11, which comprises at least 20% by weight or more of one or more compounds of the formula I according to claim 1.

13. A process for preparation of a liquid crystal medium according to claim 11, comprising mixing at least one compound of the formula I with at least one further compound, and optionally adding additives.

14. A method of generating an electro-optical effect using a liquid crystal medium according to claim 11.

15. An electro-optical liquid-crystal display comprising a liquid crystal medium according to claim 12.

16. A process for the preparation of a liquid crystal medium according to claim 11, comprising mixing at least one compound of the formula I with at least one further mesogenic compound, and optionally adding additives.

17. A process for the preparation of a liquid crystal medium according to claim 11, comprising mixing at least one compound of the formula I with at least one further ferroelectric nematic compound, and optionally adding additives.

18. A compound according to the following formula: ##STR00036## wherein R.sup.1 is an alkyl radical having 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CHCH, ##STR00037## O, S, COO or OCO in such a way that O and S atoms are not linked directly to one another, and in which one or more H atoms are each optionally replaced by halogen, or denotes H.

19. A liquid crystal medium comprising at least one compound of the formula I ##STR00038## in which X.sup.1 denotes CN, Z.sup.1 denotes C(O)O or CF.sub.2O, L.sup.1 H or CH.sub.3, and R.sup.1 denotes an alkyl radical having 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CHCH, ##STR00039## O, S, COO or OCO in such a way that O and S atoms are not linked directly to one another, and in which one or more H atoms are each optionally replaced by halogen, or denotes H.

20. The liquid crystal medium according to claim 19, wherein the medium is a ferroelectric nematic liquid crystal medium.

21. The liquid crystal medium according to claim 19, wherein the content of said at least one compound of the formula I is more than 40%.

22. A liquid crystal medium according to claim 21, wherein the content of said at least one compound of the formula I is more than 55%.

23. A liquid crystal medium according to claim 21, wherein said at least one compound of the formula I is selected from the following formulae: ##STR00040## ##STR00041## ##STR00042## ##STR00043##

Description

EXAMPLES

(1) The present invention is described in detail by the following non-restrictive examples.

Example 1: Synthesis of UUQU-4-N

(2) ##STR00018##
Step 1.1

(3) ##STR00019##

(4) 20.3 ml (203 mmol) 1,3-propanedithiol was dissolved in 25.9 ml of toluene and warmed to 80 C. A solution of 34.5 g (135.1 mmol) 3, 0.2 ml trifluoromethanesulfonic acid and 40 ml toluene was prepared and added dropwise to the dithiol solution at 80 C. After the addition was complete the mixture was stirred at 80 C. for 45 min, and then cooled to 20 C. 17.7 ml (200 mmol) trifluoromethanesulfonic acid was added dropwise during a period of 80 min keeping the temperature below 25 C. The toluene was distilled off at 80 C. and 40 mbar, 25 ml of additional toluene was added, and all volatiles were distilled off again. The crystalline residue was used for the next step without further purification.

(5) Step 1.2

(6) ##STR00020##

(7) 93.1 g (0.6 mol) 5 was suspended in 1.6 L dichloromethane and cooled to 6 C. 83.2 ml (0.6 mol) triethylamine was added dropwise at 5 C., followed by 230 g (0.5 mol) of salt 4. The mixture was stirred at 5 C. for 30 min, then cooled to 75 C. and 244.3 ml (1.5 mol) triethylamine trihydrofluoride was added dropwise. The solution was stirred for one hour at 75 C., and 128 ml (2.5 mol) of bromine dissolved in 400 ml dichloromethane was added. The mixture was stirred for 1.5 h at 70 C. and allowed to warm to 0 C. After the usual workup 132 g (62%) of 6 was obtained as slightly beige crystals.

(8) Step 1.3

(9) ##STR00021##

(10) 13.8 g (35 mmol) 6 was dissolved in 150 ml 1,4-dioxane, 1.0 g (1.4 mmol) palladium acetate, 10.4 g (0.1 mol) potassium acetate and 13.9 g (53 mmol) bis(pinacolato)boron were added. The mixture was heated under reflux overnight. After the usual workup 12.4 g (80%) of 7 was obtained as slightly yellow crystals.

(11) ##STR00022##
Step 1.4

(12) 5.4 g (23 mmol) potassium phosphate was dissolved in 10 ml water. 80 ml of toluene, 2.8 g (11.4 mmol) 1-bromo-2,6-difluoro-4-butyl benzene 8, 6.3 g (14.2 mmol) 7, 42.2 mg (0.2 mmol) palladium acetate and 126.7 mg (0.3 mmol) S-Phos (2-dicyclohexylphosphino-2,6-dimethoxybiphenyl) were added and the mixture was heated under reflux overnight. After the usual workup 3.42 g (62%) 9 (UUQU-4-N) was obtained as colorless crystals.

(13) .sup.1H NMR (400 MHz, Chloroform-d) b 7.16 (d, J=11.0 Hz, 2H), 7.07-6.99 (m, 2H), 6.91-6.81 (m, 2H), 2.69-2.61 (m, 2H), 1.69-1.57 (m, 2H), 1.39 (h, J=7.4 Hz, 2H), 0.96 (t, J=7.3 Hz, 3H).

(14) Melting point: 44 C.

(15) Clearing point: 21 C.

(16) n (20 C.)=0.12

(17) Characterization of ferroelectric-nematic behaviour:

(18) C 44 N.sub.f (21.4) I

(19) The dielectric properties are also determined.

(20) TABLE-US-00001 TABLE Measurement of at different temperatures (cooling 1/min, flat metal electrodes) T/ C. (1 kHz, T) Remark 5.0 2.34 crystalline on cooling down 7.0 7,730 10.0 11,300 12.0 13,800 14.0 16,500 16.0 19,100 18.0 21,500 19.8 23,100 .sub.max. 20.0 22,800 20.5 2.39 transition N.sub.f - isotropic 21.0 2.39 22.0 2.40

Example 2: Synthesis of UUZU-4-N

(21) ##STR00023##
Step 2.1

(22) ##STR00024##
Step 2.2

(23) 57.2 g (150 mmol) disodiumtetraborate-decahydrate, 2.8 g (4 mmol) palladium chloride, 0.2 g (4 mmol) hydrazinium hydroxide, 39.4 g (0.2 mol) 1-bromo-3,5-difluorobenzene, 42.8 g (0.2 mol) 10 and 200 ml of water were combined. The mixture was heated to reflux for 6 h. After the usual workup 50 g (88%) of 11 was obtained.

(24) ##STR00025##
Step 2.3

(25) 50 g (175 mmol) 11 was dissolved in 300 ml tetrahydrofuran and cooled to 75 C. 118 ml (193 mmol) of 15% n-butyllithum in hexane was added dropwise below 70 C. and the mixture was stirred at that temperature for 1.5 h. The mixture was poured onto 500 g of solid carbon dioxide and allowed to warm to room temperature. After the usual workup 46.8 g (82%) of 12 was obtained as colorless crystals.

(26) ##STR00026##
Step 2.4

(27) 16.3 g (50 mmol) 12, 8.5 g (55 mmol) 1-cyano-2,6-difluoro-4-hydroxy-benzene and 611 mg (5 mmol) 4-dimethylaminopyridine were combined with 200 ml dichloromethane and cooled to 0 C. Between 0 and 5 C. a solution of 11.3 g (55 mmol) N,N-dicyclohexylcarbodiimide in 50 ml dichloromethane was added dropwise. The mixture was then warmed to room temperature and stirred overnight. 1.4 g oxalic acid was added, and everything was stirred another 1.5 h. After the usual workup 20.5 g (88%) 13 (UUZU-4-N) was obtained.

(28) .sup.1H NMR (500 MHz, Chloroform-d) b 7.23-7.17 (m, 2H), 7.15-7.08 (m, 2H), 6.91-6.83 (m, 2H), 2.69-2.62 (m, 2H), 1.69-1.59 (m, 2H), 1.39 (h, J=7.4 Hz, 2H), 0.96 (t, J=7.4 Hz, 3H).

(29) Phases: K 69 N.sub.f 92 N 93 I

(30) n (20 C.): 0.16

Example 3: Synthesis of UUZU-5-N

(31) ##STR00027##

(32) The compound is prepared in analogy to Example 2.

(33) Melting point: 80 C.

(34) n (20 C.): 0.16

(35) In analogy to Examples 1 and 2 the following compounds are prepared: In the following table(s) the following abbreviations for the end groups are used

(36) ##STR00028##
General Structure

(37) ##STR00029##

(38) TABLE-US-00002 TABLE Further compound examples Example no. R.sup.1 Z.sup.1 X.sup.1 Melting point 4. H COO CN 5. CH.sub.3 COO CN 6. C.sub.2H.sub.5 COO CN 135 C. 7. n-C.sub.3H.sub.7 COO CN 104 C. 8. C.sub.2H.sub.5CH(CH.sub.3)CH.sub.2 COO CN 9. n-C.sub.6H.sub.13 COO CN 60 C. 10. n-C.sub.7H.sub.15 COO CN 11. n-C.sub.3H.sub.7CH(C.sub.2H.sub.5)CH.sub.2 COO CN 12. n-C.sub.8H.sub.17 COO CN 13. c-C.sub.3H.sub.5 COO CN 14. c-C.sub.3H.sub.5CH.sub.2 COO CN 15. c-C.sub.4H.sub.7 COO CN 16. c-C.sub.5H.sub.7 COO CN 17. c-C.sub.5H.sub.9 COO CN 18. c-C.sub.5H.sub.9CH.sub.2 COO CN 19. CH.sub.2CH COO CN 20. CH.sub.3CHCH COO CN 21. CH.sub.2CH(CH.sub.2).sub.2 COO CN 22. CH.sub.3O COO CN 23. C.sub.2H.sub.5O COO CN 104 C. 24. n-C.sub.3H.sub.7O COO CN 25. n-C.sub.4H.sub.9O COO CN 26. n-C.sub.5H.sub.11O COO CN 27. H CF.sub.2O CN 28. CH.sub.3 CF.sub.2O CN 29. C.sub.2H.sub.5 CF.sub.2O CN 84 C. 30. n-C.sub.3H.sub.7 CF.sub.2O CN 73 C. 31. n-C.sub.5H.sub.11 CF.sub.2O CN 39 C. 32. C.sub.2H.sub.5CH(CH.sub.3)CH.sub.2 CF.sub.2O CN 33. n-C.sub.6H.sub.13 CF.sub.2O CN 36 C. 34. n-C.sub.7H.sub.15 CF.sub.2O CN 35. n-C.sub.3H.sub.7CH(C.sub.2H.sub.5)CH.sub.2 CF.sub.2O CN 36. n-C.sub.8H.sub.17 CF.sub.2O CN 37. c-C.sub.3H.sub.5 CF.sub.2O CN 38. c-C.sub.3H.sub.5CH.sub.2 CF.sub.2O CN 39. c-C.sub.4H.sub.7 CF.sub.2O CN 40. c-C.sub.5H.sub.7 CF.sub.2O CN 41. c-C.sub.5H.sub.9 CF.sub.2O CN 42. c-C.sub.5H.sub.9CH.sub.2 CF.sub.2O CN 43. CH.sub.2CH CF.sub.2O CN 44. CH.sub.3CHCH CF.sub.2O CN 45. CH.sub.2CH(CH.sub.2).sub.2 CF.sub.2O CN 46. CH.sub.3O CF.sub.2O CN 47. C.sub.2H.sub.5O CF.sub.2O CN 48. n-C.sub.3H.sub.7O CF.sub.2O CN 49. n-C.sub.4H.sub.9O CF.sub.2O CN 50. n-C.sub.5H.sub.11O CF.sub.2O CN M. p.: Melting point.

MIXTURE EXAMPLES

Mixture Example 1

(39) Liquid crystal media using the compounds according to the invention are prepared in the following.

(40) The following mixtures are prepared and investigated.

(41) TABLE-US-00003 Mixture M-1 Composition Compound Concentration/ No. Abbreviation % by weight Physical properties 1 UUZU-4-N 50.0 T(N, I) = 94 C. 2 UUZU-5-N 50.0 100.0

(42) Mixture M-1 shows a ferroelectric nematic phase from 77 C. to 31 C. (upon cooling).

Mixture Example 2

(43) TABLE-US-00004 Mixture M-2 Composition Compound Concentration/ No. Abbreviation % by weight Physical properties 1 UUQU-4-N 60.0 2 UUQU-5-N 40.0 100.0

(44) Mixture M-2 shows a ferroelectric nematic phase.

Mixture Example 3

(45) TABLE-US-00005 Mixture M-3 Composition Compound Concentration/ No. Abbreviation % by weight Physical properties 1 UUQU-4-N 60.0 2 UUZU-4-N 20.0 3 UUZU-5-N 20.0 100.0

(46) Mixture M-3 shows a ferroelectric nematic phase.

Mixture Example 4

(47) TABLE-US-00006 Mixture M-4 Composition Compound Concentration/ No. Abbreviation % by weight Physical properties 1 UUQU-4-N 80.0 2 UUZU-4-N 10.0 3 UUZU-5-N 10.0 100.0

(48) Mixture M-4 shows a ferroelectric nematic phase.

Mixture Example 5

(49) TABLE-US-00007 Mixture M-5 Composition Compound Concentration/ No. Abbreviation % by weight Physical properties 1 UUQU-2-N 10.0 T(N, I) = 42 C. 2 UUQU-3-N 15.0 3 UUQU-4-N 35.0 4 UUQU-5-N 15.0 5 UUQU-6-N 5.0 6 UUZU-4-N 10.0 7 UUZU-5-N 10.0 100.0

(50) Mixture M-5 shows a ferroelectric nematic phase below 38 C.

Mixture Example 6

(51) TABLE-US-00008 Mixture M-6 Composition Compound Concentration/ No. Abbreviation % by weight Physical properties 1 UUQU-2-N 10.0 T(N, I) = 83 C. 2 UUQU-3-N 12.0 3 UUQU-4-N 17.0 4 UUZU-3-N 6.0 5 UUZU-4-N 14.0 6 UUZU-5-N 6.0 7 GUZU-4-N 8.0 8 GUUQU-3-N 8.0 9 GUUQU-4-N 12.0 10 DUUQU-4-N 7.0 100.0

(52) Mixture M-6 shows a ferroelectric nematic phase below 73 C.

(53) Further combinations of the embodiments of the current invention and variants of the invention are also disclosed by the claims.

(54) Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. 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.

(55) 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.