Liquid crystalline medium

1. A liquid-crystalline medium containing a mixture of polar compounds having negative dielectric anisotropy (Δε), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δε of ≤−2.3, and comprises

at least two compounds of formula IA, IB and/or II

in which

R 1 and R 2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, in which one or more CH 2 groups are each optionally, independently of one another, replaced by —O—, —S—, , —C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and

v denotes 1 to 6,

and

at least one compound of formula IIIa and/or IIIb

wherein

alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,

and

at least a compound of formula III-e

wherein

alkyl is defined as above, and

alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms,

and

at least one compound of formula B-4

wherein

alkyl and alkyl* are defined as above; and

wherein

(a) the proportion of compounds of the formulae IA and/or IB in the mixture as a whole is at least 10% by weight, and/or

(b) the proportion of compounds of the formula II in the mixture as a whole is at least 10% by weight.

2. A liquid-crystalline medium according to claim 1 , which has a clearing point of 60-90° C.

3. A liquid-crystalline medium according to claim 1 , wherein the medium has a & value of −2.3 to −5.5.

4. A liquid-crystalline medium according to claim 1 , wherein the medium having a clearing point of 70° C.±5° C. and a Δε of −3.0±0.6 has the following rotational viscosities γ 1 at a defined Δn value:

Δn

γ 1

0.08 ± 0.005

≤125 mPa · s

0.09 ± 0.005

≤130 mPa · s

0.10 ± 0.005

≤135 mPa · s

0.11 ± 0.005

≤145 mPa · s

0.12 ± 0.005

≤150 mPa · s

0.13 ± 0.005

≤160 mPa · s

0.15 ± 0.01

≤170 mPa · s.

5. A liquid-crystalline medium containing a mixture of polar compounds having negative dielectric anisotropy (Δε), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δε of ≤−2.3, and comprises

at least two compounds of formula IA, IB and/or II

in which

R 1 and R 2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, in which one or more CH 2 groups are each optionally, independently of one another, replaced by —O—, —S—, , —C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and

v denotes 1 to 6,

and

at least one compound of formula IIIa and/or IIIb

wherein

alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,

and

at least a compound of formula III-e

wherein

alkyl is defined as above, and

alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms,

and

at least one compound of formula B-4

wherein

alkyl and alkyl* are defined as above; and

wherein the medium having a clearing point of 70° C.±5° C. and a Δε of −4.0±0.4 has the following rotational viscosities γ 1 at a defined Δn value:

Δn

γ 1

0.08 ± 0.005

≤140 mPa · s

0.09 ± 0.005

≤165 mPa · s

0.10 ± 0.005

≤185 mPa · s

0.11 ± 0.005

≤190 mPa · s

0.12 ± 0.005

≤195 mPa · s

0.13 ± 0.005

≤205 mPa · s

0.15 ± 0.01

≤220 mPa · s.

6. A liquid-crystalline medium containing a mixture of polar compounds having negative dielectric anisotropy (Δε), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δε of ≤−2.3, and comprises

at least two compounds of formula IA, IB and/or II

in which

R 1 and R 2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, in which one or more CH 2 groups are each optionally, independently of one another, replaced by —O—, —S—, , —C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and

v denotes 1 to 6,

and

at least one compound of formula IIIa and/or IIIb

wherein

alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,

and

at least a compound of formula III-e

wherein

alkyl is defined as above, and

alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms,

and

at least one compound of formula B-4

wherein

alkyl and alkyl* are defined as above; and

wherein the medium having a clearing point of 70° C.±5° C. and a Δε of −5.0±0.6 has the following rotational viscosities γ 1 at a defined Δn value:

Δn

γ 1

0.08 ± 0.005

≤185 mPa · s

0.09 ± 0.005

≤200 mPa · s

0.10 ± 0.005

≤210 mPa · s

0.11 ± 0.005

≤220 mPa · s

0.12 ± 0.005

≤230 mPa · s

0.13 ± 0.005

≤250 mPa · s

0.15 ± 0.01

≤270 mPa · s.

7. A liquid-crystalline medium containing a mixture of polar compounds having negative dielectric anisotropy (Δε), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δε of ≤−2.3, and comprises

at least two compounds of formula IA, IB and/or II

in which

R 1 and R 2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, in which one or more CH 2 groups are each optionally, independently of one another, replaced by —O—, —S—, , —C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and

v denotes 1 to 6,

and

at least one compound of formula IIIa and/or IIIb

wherein

alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,

and

at least a compound of formula III-e

wherein

alkyl is defined as above, and

alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms,

and

at least one compound of formula B-4

wherein

alkyl and alkyl* are defined as above; and

wherein the medium having a clearing point of 90° C.±5° C. and a Δε of −3.0±0.6 has the following rotational viscosities γ 1 at a defined Δn value:

Δn

γ 1

0.08 ± 0.005

≤160 mPa · s

0.09 ± 0.005

≤170 mPa · s

0.10 ± 0.005

≤180 mPa · s

0.11 ± 0.005

≤190 mPa · s

0.12 ± 0.005

≤200 mPa · s

0.13 ± 0.005

≤210 mPa · s

0.15 ± 0.01

≤220 mPa · s.

8. A liquid-crystalline medium containing a mixture of polar compounds having negative dielectric anisotropy (Δε), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δε of ≤−2.3, and comprises

at least two compounds of formula IA, IB and/or II

in which

R 1 and R 2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, in which one or more CH 2 groups are each optionally, independently of one another, replaced by —O—, —S—, , —C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and

v denotes 1 to 6,

and

at least one compound of formula IIIa and/or IIIb

wherein

alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,

and

at least a compound of formula III-e

wherein

alkyl is defined as above, and

alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms,

and

at least one compound of formula B-4

wherein

alkyl and alkyl* are defined as above; and

wherein the medium having a clearing point of 90° C.±5° C. and a Δε of −4.0±0.4 has the following rotational viscosities γ 1 at a defined Δn value:

Δn

γ 1

0.08 ± 0.005

≤185 mPa · s

0.09 ± 0.005

≤195 mPa · s

0.10 ± 0.005

≤215 mPa · s

0.11 ± 0.005

≤215 mPa · s

0.12 ± 0.005

≤215 mPa · s

0.13 ± 0.005

≤235 mPa · s

0.15 ± 0.01

≤250 mPa · s.

9. A liquid-crystalline medium containing a mixture of polar compounds having negative dielectric anisotropy (Δε), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δε of ≤−2.3, and comprises

at least two compounds of formula IA, IB and/or II

in which

R 1 and R 2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, in which one or more CH 2 groups are each optionally, independently of one another, replaced by —O—, —S—, , —C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and

v denotes 1 to 6,

and

at least one compound of formula IIIa and/or IIIb

wherein

alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,

and

at least a compound of formula III-e

wherein

alkyl is defined as above, and

alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms,

and

at least one compound of formula B-4

wherein

alkyl and alkyl* are defined as above; and

wherein the medium having a clearing point of 90° C.±5° C. and a Δε of −5.0±0.6 has the following rotational viscosities γ 1 at a defined Δn value:

Δn

γ 1

0.08 ± 0.005

≤280 mPa · s

0.09 ± 0.005

≤275 mPa · s

0.10 ± 0.005

≤275 mPa · s

0.11 ± 0.005

≤275 mPa · s

0.12 ± 0.005

≤280 mPa · s.

10. A liquid-crystalline medium according to claim 1 , which has thresholds (capacitive) in the range 1.8-2.3 V.

11. A liquid-crystalline medium containing a mixture of polar compounds having negative dielectric anisotropy (Δε), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δε of ≤−2.3, and comprises

at least two compounds of formula IA, IB and/or II

in which

R 1 and R 2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, in which one or more CH 2 groups are each optionally, independently of one another, replaced by —O—, —S—, , —C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and

v denotes 1 to 6,

and

at least one compound of formula IIIa and/or IIIb

wherein

alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,

and

at least a compound of formula III-e

wherein

alkyl is defined as above, and

alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms,

and

at least one compound of formula B-4

wherein

alkyl and alkyl* are defined as above,

and

one or more compounds of formula III, which are not a compound of any of formulae IIIa, IIIb and II-e,

in which

R 31 and R 32 each, independently of one another, denote a straight-chain alkyl, alkylalkoxy or alkoxy radical having up to 12 C atoms, and

12. A liquid-crystalline medium according to claim 1 , which comprises two, three, four, five or six compounds of the formulae IA, IB and/or II.

13. A liquid-crystalline medium according to claim 1 , wherein the proportion of compounds of the formulae IA and/or IB in the mixture as a whole is at least 10% by weight.

14. A liquid-crystalline medium according to claim 1 , wherein the proportion of compounds of the formula II in the mixture as a whole is at least 10% by weight.

15. A liquid-crystalline medium according to claim 11 , wherein the proportion of the one or more compounds of formula II in the mixture as a whole is at least 5% by weight.

16. A liquid-crystalline medium according to claim 1 , which contains

10-40% by weight of one or more compounds of the formulae IA and IB, and

10-40% by weight of one or more compounds of the formula II.

17. An electro-optical display having active-matrix addressing based on the ECB, PA LCD, FFS or the IPS effect, which contains, as dielectric, a liquid-crystalline medium containing a mixture of polar compounds having negative dielectric anisotropy (Δε), which has a value for the ratio γ 1 /Δn 2 in the range 6-45 with a clearing point of >60° C. and a Δε of ≤−2.3, and comprises

at least two compounds of formula IA, IB and/or II

in which

R 1 and R 2 each, independently of one another, denote an alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, in which one or more CH 2 groups are each optionally, independently of one another, replaced by —O—, —S—, , —C≡C—, —CF 2 O—, —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that O atoms are not linked directly to one another, and

v denotes 1 to 6,

and

at least one compound of formula IIIa and/or IIIb

wherein

alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms,

and

at least a compound of formula III-e

wherein

alkyl is defined as above, and

alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms,

and

at least one compound of formula B-4

wherein

alkyl and alkyl* are defined as above.

18. A liquid-crystalline medium according to claim 1 , which comprises at least one compound of each of formula IIIa and IIIb.

19. A liquid-crystalline medium according to claim 1 , which comprises at least one of each of the compounds of formulae IA, IB and II.