Liquid-crystal medium, and electro-optical display containing same

1. A nematic liquid-crystal medium, wherein said medium comprises

a) a dielectrically negative liquid-crystalline component, component A, which comprises one or more dielectrically negative compound(s) of the formula I

in which

R 11 and R 12 are each, independently of one another, alkyl having from 1 to 7 carbon atoms, alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

one of

Z 11 and Z 12 are each, independently of one another, —CH 2 —CH 2 —, —CH 2 —CF 2 —, —CF 2 —CH 2 —, —OCH 2 —, —CH 2 O—, —OCF 2 —, —CF 2 O— or a single bond, and

n is 1,

where one or more H atoms in the third phenyl ring may optionally be replaced by F atoms if

 and

b) a further dielectrically negative liquid-crystalline component, component B, which is different from component A.

2. A liquid-crystal medium, wherein component B comprises one or more compounds selected from the group consisting of the compounds of the formulae II and III

in which

R 21 , R 22 , R 31 and R 32 are each, independently of one another, alkyl or alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z 21 , Z 22 , Z 31 and Z 32 are each, independently of one another, —CH 2 —CH 2 —, —CH═CH—, —C≡C—, —COO— or a single bond,

m is 0 or 1, and

3. A liquid-crystal medium according to claim 1 , wherein component B comprises one or more compounds selected from formula II

in which

R 21 and R 22 are each, independently of one another, alkyl or alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z 21 and Z 22 are each, independently of one another, —CH 2 —CH 2 —, —CH═CH—, —C≡C—, —COO— or a single bond, and

m is 0 or 1.

4. The liquid-crystal medium according to claim 1 , wherein component B comprises one or more compounds selected from formula III

in which

R 31 and R 32 are each, independently of one another, alkyl or alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z 31 and Z 32 are each, independently of one another, —CH 2 —CH 2 —, —CH═CH—, —C≡C—, —COO— or a single bond, and

5. A liquid-crystal medium according to claim 1 , wherein said medium further comprises a dielectrically neutral liquid-crystalline component, component C.

6. A liquid-crystal medium according to claim 1 , wherein said medium further comprises a dielectrically neutral liquid-crystalline component, component C, of formula IV

in which

R 41 and R 42 are each, independently of one another alkyl having from 1 to 7 carbon atoms, alkoxy having from 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z 41 , Z 42 and Z 43 are each, independently of one another, —CH 2 —CH 2 —, —CH═CH—, —COO— or a single bond,

 and

o and p, are each, independently of one another, 0 or 1.

7. A liquid-crystal medium according to claim 1 , wherein said medium further comprises a dielectrically positive liquid-crystalline component, component D.

8. A liquid-crystal medium according to claim 1 , wherein said medium further comprises a dielectrically positive liquid-crystalline component, component D, of formula V

in which

R 5 is alkyl or alkoxy having from 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z 51 , Z 52 and Z 53 are each, independently of one another, —CH 2 —CH 2 —,—CH═CH—, —C≡C—, —COO— or a single bond,

X 5 is F, OCF 2 H or OCF 3 ,

Y 51 and Y 52 are each, independently of one another, H or F, and

q and r are each, independently of one another, 0 or 1.

9. The liquid-crystal medium of claim 2 further comprising a dielectrically neutral liquid-crystalline component, component C.

10. The liquid-crystal medium of claim 2 further comprising a dielectrically positive liquid-crystalline component, component D.

11. A liquid-crystal medium according to claim 1 , wherein said medium comprises one or more compounds of formula VI

in which

R 61 and R 62 are each, independently of one another, alkyl having from 1 to 7 carbon atoms, alkoxy having from 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z 61 , Z 62 and Z 63 are each, independently of one another, —CH 2 —CH 2 —, —CH═CH—, —COO— or a single bond,

at least one of the

in which at least one of L 61 and L 62 is N and the other is N or C—F, and the other

 and

q and r are each, independently of one another, 0 or 1.

12. A liquid-crystal medium according to claim 1 , wherein said medium comprises one or more compounds of formula VII

in which

R 71 and R 72 are each, independently of one another, alkyl having from 1 to 7 carbon atoms, alkoxy having from 1 to 7 carbon atoms, or alkenyloxy having from 2 to 7 carbon atoms, and

X 7 is F, Cl, CN or NCS,

and s is 0 or 1.

13. In an electro-optical display containing a liquid-crystal medium, the improvement wherein said medium is one according to claim 1 .

14. A display according to claim 13 , wherein said display is an active matrix display.

15. A display of claim 14 , wherein said display is an ECB or IPS display.

16. In a method of generating an electro-optical effect using an electro-optical display, the improvement wherein said display is one according to claim 13 .

17. A liquid-crystal medium according to claim 6 , wherein R 41 and R 42 are each, independently of one another n-alkyl having from 1 to 7 carbon atoms, n-alkoxy having from 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 4 carbon atoms.

18. A liquid-crystal medium according to claim 8 , wherein Y 51 is F.

19. A liquid-crystal medium according to claim 8 , wherein Y 51 and Y 52 are each F.

20. A liquid-crystal medium according to claim 8 , wherein X 5 is F or OCF 2 H, and Y 52 is F.

21. A liquid-crystal medium according to claim 11 , wherein R 61 and R 62 are each, independently of one another n-alkyl having from 1 to 7 carbon atoms, n-alkoxy having from 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 4 carbon atoms.

22. A liquid-crystal medium according to claim 12 , wherein R 71 and R 72 are each, independently of one another n-alkyl having from 1 to 7 carbon atoms, n-alkoxy having from 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 4 carbon atoms.

23. A liquid-crystal medium according to claim 12 , wherein X 7 is F or CN.

24. A liquid-crystal medium according to claim 12 , wherein

25. A liquid-crystal medium according to claim 1 , wherein

26. A liquid-crystal medium according to claim 1 , wherein said component A contains one or more compounds of formula I-2c

27. A liquid-crystal medium according to claim 1 , wherein said component A contains one or more compounds of formula I-3b.

28. A liquid-crystal medium according to claim 1 , wherein said component A contains one or more compounds of formula I-3c

29. A liquid-crystal medium according to claim 1 , wherein said medium contains from 5% to 85% by weight of compounds of the formula I.

30. A liquid-crystal medium according to claim 2 , wherein said medium contains from 5% to 85% by weight of compounds of the formulae II and III.

31. A liquid-crystal medium according to claim 6 , wherein said medium contains up to 50% by weight of compounds of the formula IV.

32. A liquid-crystal medium according to claim 8 , wherein said medium contains up to 40% by weight of compounds of the formula V.

33. A liquid-crystal medium according to claim 2 , wherein said medium further comprises:

a dielectrically neutral liquid-crystalline component, component C, of formula IV

in which

R 41 and R 42 are each, independently of one another alkyl having from 1 to 7 carbon atoms, alkoxy having from 1 to 7 carbon atoms or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z 41 , Z 42 and Z 43 are each, independently of one another, —CH 2 —CH 2 —, —CH═CH—, —COO— or a single bond,

 and

o and p, are each, independently of one another, 0 or 1; and

a dielectrically positive liquid-crystalline component, component D, of formula V

in which

R 5 is alkyl or alkoxy having from 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having from 2 to 7 carbon atoms,

Z 51 , Z 52 and Z 53 are each, independently of one another, —CH 2 —CH 2 —, —CH═CH—, —C═C—, —COO— or a single bond,

X 5 is F, OCF 2 H or OCF 3 ,

Y 51 and Y 52 are each, independently of one another, H or F, and

q and r are each, independently of one another, 0 or 1.

34. A liquid-crystal medium according to claim 33 , wherein said medium contains from 10% to 35% by weight of compounds of the formula I, from 50% to 90% by weight of compounds of the formulae II and III, from 0% to 40% by weight of compounds of the formula IV, and from 0% to 20% by weight of compounds of the formula V.

35. A liquid-crystal medium according to claim 33 , wherein said medium contains from 15% to 30% by weight of compounds of the formula I, from 60% to 80% by weight of compounds of the formulae II and III, from 0% to 20% by weight of compounds of the formula IV and from 0% to 5% by weight of compounds of the formula V.