Liquid crystal mixture and liquid crystal display

1. A compound of formula I,

wherein

A 11 denotes a radical

where, in addition, one or more H atoms in these radical may each be replaced by L, and/or one or more and/or one or more CH groups may each be replaced by N,

A denotes, independently of one another, in each occurrence

a) the group consisting of 1,4-phenylene and 1,3-phenylene, wherein, in addition, one or two CH groups may each be replaced by N and wherein, in addition, one or more H atoms may each be replaced by L,

b) the group consisting of saturated, partially unsaturated or fully unsaturated, and optionally substituted, polycyclic radicals having 5 to 20 cyclic C atoms, one or more of which may, in addition, be replaced by heteroatoms, selected from the group consisting of

where, in addition, one or more H atoms in these radicals may each be replaced by L, and/or one or more double bonds may each be replaced by single bonds, and/or one or more CH groups may each be replaced by N,

c) group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, wherein, in addition, one or more non-adjacent CH 2 groups may each be replaced by —O— or —S— and wherein, in addition, one or more H atoms may each be replaced by F, or

d) a group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L,

L on each occurrence, identically or differently, denotes —OH, —F, —Cl, —Br, —I, —CN, —NO 2 , SF 5 , —NCO, —NCS, —OCN, —SCN, —C(═O)N(R z ) 2 , —C(═O)R z , —N(R z ) 2 , optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched or cyclic alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may each be replaced by F or Cl, or X 21 -S p 21 -R 21 ,

M denotes —O—, —S—, —CH 2 —, —CHR z — or —CR y R z —, and

R y and R z each, independently of one another, denote H, CN, F or alkyl having 1-12 C atoms, wherein, in addition, one or more H atoms may each be replaced by F,

Y 11 and Y 12 each, independently of one another, denote H, F, phenyl or optionally fluorinated alkyl having 1-12 C atoms,

Z denotes, independently of each other, in each occurrence, a single bond, —COO—, —OCO—, —O—CO—O—, —OCH 2 —, —CH 2 O—, —OCF 2 —, —CF 2 O—, —(CH 2 ) n —, —CF 2 CF 2 —, —CH═CH—, —CF═CF—, —CH═CH—COO—, —OCO—CH═CH—, —CO—S—, —S—CO—, —CS—S—, —S—CS—, —S—CSS— or —C≡C—,

n denotes an integer between 2 and 8,

o and p denote each and independently 0, 1 or 2,

X 11 and X 21 denote independently from one another, in each occurrence a single bond, —CO—O—, —O—CO—, —O—COO—, —O—, —CH═CH—, —C≡C—, —CF 2 —O—, —O—CF 2 —, —CF 2 —CF 2 —, —CH 2 —O—, —O—CH 2 —, —CO—S—, —S—CO—, —CS—S—, —S—CS—, —S—CSS— or —S—,

Sp 11 and Sp 21 denote each and independently, in each occurrence a single bond or a spacer group comprising 1 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH 2 groups may also each be replaced by —O—, —S—, —NH—, —N(CH 3 )—, —CO—, —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O—, —CF 2 —, —CF 2 O—, —OCF 2 — —C(OH)—, —CH(alkyl)-, —CH(alkenyl)-,-CH(alkoxyl)-, —CH(oxaalkyl)-, —CH═CH— or C≡C—, however in such a way that no two O-atoms are adjacent to one another and no two groups selected from —O—CO—, —S—CO—, —O—COO—, —CO—S—, —CO—O— and —CH═CH— are adjacent to each other,

R 11 denotes P,

R 21 denotes P, or halogen, CN, optionally fluorinated alkyl or alkenyl with up to 15 C atoms in which one or more non adjacent CH 2 -groups may each be replaced by —O—, —S—, —CO—, —C(O)O—, —O—C(O)—, O—C(O)—O—, and

P each and independently from another in each occurrence a polymerizable group.

2. The compound according to claim 1 , wherein the compound is selected from compounds of -sub-formulae I-1 to I-9,

wherein

R 11 , R 21 , A 11 , X 11 , X 12 , Y 11 , Y 12 , Sp 11 , and Sp 12 have one of the meanings as given above in claim 1 , A 12 to A 23 have one of the meanings for A as given in claim 1 , and Z 11 to Z 22 have one of the meanings for Z as given above in claim 1 .

3. The compound according to claim 1 , wherein the compound is selected from compounds sub-formulae I-1a-1, I-2a-1, and I-3a-1,

wherein

R 11 , R 21 , X 11 , X 21 , Sp 11 , and Sp 21 have one of the meanings as given above in claim 1 , Z 11 and Z 21 have one of the meanings for Z as given above in claim 1 and

the group

is each and independently

or

denotes

furthermore

wherein L is F, Cl, CH 3 , OCH 3 and COCH 3 or alkylene having 1 to 6 C atoms, or X 21 -Sp 21 -R 21 .

4. The compound according to claim 1 , wherein said compound is selected from compounds of sub formulae I-3a-1a, I-3a-1b, and I-3a-1c,

wherein

R 11 , R 21 , X 21 , and Sp 21 have one of the meanings as given above in claim 1 , Z 21 has one of the meanings for Z as given above under claim 1 , r, s, t and q denote each and independently from another an integer from 1 to 8, Y denotes each and independently from each other methyl or H, and

the group

is each and independently

or

denotes

furthermore

wherein L is F, Cl, CH 3 , OCH 3 and COCH 3 or alkylene having 1 to 6 C atoms, or X 21 -Sp 21 -R 21 .

5. The compound according to claim 1 , wherein said compound is selected from compounds of sub-formulae I-3-1a-1 to I-3-1a-8,

wherein Sp 21 has one of the meanings as given above in formula I, and L denotes F, Cl, OCH 3 and COCH 3 or alkylene having 1 to 6 C atoms.

6. The compound according to claim 1 , wherein said compound is selected from compounds of sub-formulae I-3-1b-1 to I-3-1b-4,

wherein Sp 21 has one of the meanings as given above in formula I, and L denotes F, Cl, OCH 3 and COCH 3 or alkylene having 1 to 6 C atoms.

7. A method of photoaligning a liquid crystal mixture comprising irradiating a liquid crystal mixture with linearly polarized light wherein said liquid crystal mixture contains one or more compounds of formula I according to claim 1 .

8. A liquid crystal mixture, comprising:

a component A) comprising one or more compounds of formula I according to claim 1 , and

a liquid-crystalline component B), comprising one or more mesogenic or liquid-crystalline compounds.

9. The liquid crystal mixture according to claim 8 , wherein the total concentration of compounds of formula I in the mixture is in the range of from 0.01 to 10% by weight.

10. The liquid crystal mixture according to claim 8 , further comprising a polymerizable component C) comprising one or more polymerizable mesogenic or polymerizable isotropic compounds.

11. The liquid crystal mixture according to claim 10 , wherein the concentration of polymerizable mesogenic or polymerizable isotropic compounds is in the range of from 0.01 to 10% by weight.

12. The liquid crystal mixture according to claim 10 , wherein said mixture contains one or more polymerizable compounds of formula P

P a -(Sp a ) s1 -A 2 -(Z a -A 1 ) n2 -(Sp b ) s2 —Pb  P

wherein

P a , P b each, independently of one another, denote a polymerizable group,

Sp a , Sp b on each occurrence, identically or differently, denote a spacer group,

s1, s2 each, independently of one another, are 0 or 1,

A 1 , A 2 each, independently of one another, denote a radical selected from the following groups:

a) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene and 4,4’-bicyclohexylene, wherein, in addition, one or more non-adjacent CH 2 groups may each be replaced by —O—or —S— and wherein, in addition, one or more H atoms may each be replaced by F,

b) the group consisting of 1,4-phenylene and 1,3-phenylene, wherein, in addition, one or two CH groups may each be replaced by N and wherein, in addition, one or more H atoms may each be replaced by L,

c) the group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L,

d) the group consisting of saturated, partially unsaturated or fully unsaturated, and optionally substituted, polycyclic radicals having 5 to 20 cyclic C atoms, one or more of which may, in addition, be replaced by heteroatoms, that are selected from:

where, in addition, one or more H atoms in these radicals may be replaced by L, and/or one or more double bonds may each be replaced by single bonds, and/or one or more CH groups may each be replaced by N,

n2 is 0,1,2 or 3,

Z 1 in each case, independently of one another, denotes —CO—O—, —O—CO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —(CH 2 ) n — where n is 2, 3 or 4, —O—, —CO—, —C(R 0 R 00 )—, —CH 2 CF 2 —, —CF 2 CF 2 — or a single bond,

L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF 5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to 12 C atoms,

R 0 , R 00 each, independently of one another, denote H, F or straight-chain or branched alkyl having 1 to 12 C atoms, wherein, in addition, one or more H atoms may each be replaced by F,

M denotes —O—, —S—, —CH 2 —, —CHY 1 — or —CY 1 Y 2 —, and

Y 1 and Y 2 each, independently of one another, have one of the meanings indicated above for R 0 or denote Cl or CN.

13. The liquid crystal mixture according to claim 8 , wherein component B has negative dielectric anisotropy.

14. The liquid crystal mixture according to claim 13 , wherein component B comprises one or more compounds selected from formulae CY and PY:

wherein

a is 1 or 2,

b is 0 or 1,

denotes

R 1 and R 2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH 2 groups may each be replaced by —O—, —CH═CH—, —CO—, —O—CO— or —CO—O—in such a way that O atoms are not linked directly to one another,

Z X denotes —CH═CH—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —O—, —CH 2 —, —CH 2 CH 2 — or a single bond, and

L 1-4 each, independently of one another, denote F, Cl, OCF 3 , CF 3 , CH 3 , CH 2 F, CHF 2 .

15. The liquid crystal mixture according to claim 8 , wherein component B has positive dielectric anisotropy.

16. The liquid crystal mixture according to claim 15 , wherein component B comprises one or more compounds selected from compounds of formulae II and III,

wherein

R 20 each, identically or differently, denote a halogenated or unsubstituted alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH 2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF 2 O—, —CH═CH—,

—O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another,

X 20 each, identically or differently, denote F, Cl, CN, SF 5 , SCN, NCS, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical, each having up to 6 C atoms, and

Y 20-24 each, identically or differently, denote H or F,

W denotes H or methyl, and

each, identically or differently, denote

17. The liquid crystal mixture according to claim 15 , wherein said mixture comprises one or more compounds selected from compounds of formulae XI and XII

wherein

R 20 denotes a halogenated or unsubstituted alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH 2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF 2 O—, —CH═CH—,

—O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another,

X 20 each, identically or differently, denote F, Cl, CN, SF 5 , SCN, NCS, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical, each having up to 6 C atoms,

Y 20-23 each identically or differently, denote H or F,

W denotes H or methyl, and

each, independently of one another, denote

and

denotes

18. The liquid crystal mixture according to claim 8 , wherein component B comprises one or more compounds of formula ZK:

in which the individual radicals have the following meanings:

denotes

denotes

R 3 and R 4 each, independently of one another, denote alkyl having 1 to 12 C atoms, in which, in addition, one or two non-adjacent CH 2 groups may be replaced by —O—, —CH═CH—, —CO—, —O—CO— or —CO—O— in such a way that O atoms are not linked directly to one another, and

Z y denotes —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —CO—O—, —O—CO—, -C 2 F 4 —, —CF═CF—, —CH═CH—CH 2 O— or a single bond.

19. The liquid crystal mixture according to claim 8 , wherein component B comprises one or more compounds of the following formula

wherein the propyl, butyl and pentyl groups are straight-chain groups.

20. The liquid crystal mixture according to claim 8 , wherein component B comprises one or more compounds selected from the formulae B1 to B3:

in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms.

21. The liquid crystal mixture according to claim 8 , wherein component B comprises one or more compounds selected from the following formulae:

in which alkyl* denotes an alkyl radical having 1-6 C atoms.

22. A method of photoaligning the liquid crystal mixture according to claim 8 comprising irradiating the liquid crystal mixture with linearly polarized light.

23. A process the fabrication of a liquid crystal display, comprising:

providing a first substrate which includes a pixel electrode and a common electrode for generating an electric field substantially parallel to a surface of the first substrate in the pixel region;

providing a second substrate, the second substrate being disposed opposite to the first substrate;

interposing a liquid crystal mixture according to claim 8 ;

irradiating the liquid crystal mixture with linearly polarized light causing photoalignment of the liquid crystal; and

curing the polymerizable compounds of the liquid crystal mixture by irradiation with ultraviolet light or visible light having a wavelength of 450 nm or below.

24. The process according to claim 23 , wherein the linearly polarized light is ultraviolet light or visible light having a wavelength of 450 nm or below.

25. A display obtainable by a process according to claim 23 .

26. The display according to claim 25 , wherein component B is homogeneously aligned without the application of an electric field.

27. The display according to claim 25 , wherein the display is an IPS or FFS display.