Optically active materials

1. A compound of formula I:

in which:

A 1 to A 4 each independently represent hydrogen;

an optionally-substituted methyl group;

or an optionally-substituted hydrocarbon group of 2 to 80 C-atoms, in which one or more C-atoms may be replaced by a heteroatom, in such a way that oxygen atoms are not linked to one another, selected from formula (II):

P-(Sp 1 ) k1 −(X 1 ) t1 −  (II)

wherein:

P is hydrogen or a polymerisable group selected from groups comprising CH 2 ═CW—, CH 2 ═CW—O—, CH 2 ═CW—COO—, CH 2 ═C(Ph)—COO—, CH 2 CH—COO—Ph—, CH 2 CW—CO—NH—, CH 2 ═C(Ph)—CONH—, CH 2 ═C(COOR′)—CH 2 —COO—, CH 2 ═CH—O—, CH 2 ═CH—OOC—, (Ph)—CH═CH—, CH 3 —CH═N—(CH 2 ) m3 , HO—, HS—, HO—(CH 2 ) m3 —, HS—(CH 2 ) m3 —, HO(CH 2 ) m3 COO—, HS(CH 2 ) m3 COO—, HOC(O)—, CH 2 ═CH—Ph—(O) m4

 wherein:

W represents H, F, Cl, Br or I or a C 1-5 alkyl group:

m3 is an integer having a value of from 1 to 9;

m4 is an integer having a value of 0 or 1,

R′ represents a C 1-5 alkyl group; and

R″ represents a C 1-5 alkyl group, methoxy, cyano, F, Cl, Br or I;

Sp 1 represents an optionally-substituted C 1-20 alkylene group, in which one or more C-atoms may be replaced by a heteroatom;

k 1 is an integer having a value of from 0 to 4;

X 1 represents —O—, —S—, —NH—, N(CH 3 )—, —CH(OH)—, —CO—, —CH 2 (CO)—, —SO—, —CH 2 (SO)—, —SO 2 —, —CH 2 (SO 2 )—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —SOO—, —OSO—, —SOS—, —CH 2 —CH 2 —, —OCH 2 —, —CH 2 O—, —CH═CH—, or 13 C≡C—; and

t 1 is an integer having a value of 0 or 1:

wherein the term Ph denotes phenylene and (Ph) denotes phenyl;

E 1 and E 2 each independently represent hydrogen; an optionally-substituted methyl group; or an optionally-substituted hydrocarbon group of 2 to 80 C-atoms, in which one or more C-atoms may be replaced by a heteroatom, in such a way that oxygen atoms are not linked to one another, selected from formula (II):

P-(Sp 1 ) k1 (X 1 ) t1 —  (II)

B 1 and B 2 each independently represent a group of formula (IV):

(X 2 ) t2 -(Sp 2 ) k2 -(X 3 ) t3   (IV)

 wherein:

Sp 2 represents a C 1-20 alkylene group;

X 2 and X 3 each independently represent —O—, —S—, —NH—, N(CH 3 )—, —CH(OH)—, —CO—, —CH 2 (CO)—, —SO—, —CH 2 (SO)—, —SO 2 —, —CH 2 (SO 2 )—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —SOO—, —OSO—, —SOS—, —CH, —CH 2 —, —OCH 2 —, —CH 2 O—, —CH═CH—, —C≡C— or a single bond;

k2 is an integer, having a value of 0 or 1; and

t 2 and t 3 are integers, each independently having a value of 0 or 1;

with the proviso that oxygen atoms are not linked one to another;

MG 1 and MG 2 each independently represent an optionally-substituted aromatic or non-aromatic carbocyclic or heterocyclic ring system, with 1 to 80 C-atoms with a mesogenic architecture;

CG is a chiral group having at least two chiral centers, derived from a sugar, from an optically active biaryl group, or from a bifunctional or polyfunctional compound comprising an optically active alcohol, glycol, or amino acid; and

n1 and n2 are each independently 1 or 2, where “n1=2”, or “n2=2”, indicates the presence of two separate linkages via the groups B 1, or the groups B 2, between the groups MG 1 and CG, or CG and MG 2 ;

and in which further the substructures A 1 -MG 1 -A 2 and A 3 -MG 2 -A 4 are rod-like shaped organic residues and each have a longitudinal axis and are linked lateral to the said longitudinal axis to B 1 and B 2 , respectively.

2. A compound as claimed claim 1 in which:

n1=n2=1.

3. A compound as claimed in claim 1 , in which at least one of A 1 to A 4 , E 1 and E 2 includes a polymerisable group.

4. A compound as claimed in claim 1 , in which one or more of CH 2 groups present in the hydrocarbon chain of the optionally-substituted C 1-20 alkylene group Sp 1 is replaced, independently, by one or more groups selected from —O—, —S—, —NH—, N(CH 3 )—, —CH(OH)—, —CO—, —CH 2 (CO)—, —SO—, —CH 2 (SO)—, —SO 2 —, —CH 2 (SO 2 )—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—, —SOO—, —OSO—, —SOS—, —C≡C—, —(CF 2 )— r , —(CD 2 ) s — or C(W 1 )═C(W 2 )—, with the proviso that no two oxygen atoms are directly linked to each other, wherein W 1 and W 2 each represent, independently, H, H—(CH 2 ) q1 — or Cl and the integers r, s and q1 each independently represent a number of between 1 and 15.

5. A compound as claimed in claim 1 , in which A 1 to A 4 and E 1 to E 2 each independently represent a group of formula (III):

P 2 -Sp 5 -X 4 -  (III)

wherein:

P 2 represents hydrogen, CH 2 ═CW 5 — or CH 2 ═CW 5 —(CO) v2 O—,

 wherein:

W 5 represents H, CH 3 , F, Cl, Br or I; and

v2 is 0 or 1,

R′ represents a C 1-5 alkyl group; and

R″ represents a C 1-5 alkyl group, methoxy, cyano, F, Cl, Br or I;

Sp 5 represents a C 1-20 straight-chain alkylene group; and

X 4 represents —O—, —CO—, —COO—, —OCO—, —C≡C—, or a single bond.

6. A compound as claimed in claim 1 , in which B 1 and B 2 each independently represent a group of formula (IV), wherein:

X 2 to X 3 each independently represent —O—, —CO—, —COO—, —OCO—, —C≡O—, or a single bond; and

Sp 2 represents a C 1-20 straight-chain alkylene group.

7. A compound as claimed in claim 1 , in which at least one of MG 1 and MG 2 represents a mesogenic group comprising at least two optionally-substituted aromatic or non-aromatic carbocyclic or heterocyclic ring systems.

8. A compound as claimed in claim 1 , in which one or more of MG 1 and MG 2 represents a mesogenic group comprising 1 to 4 aromatic or non-aromatic carbocyclic or heterocyclic ring systems and optionally up to 3 bridging groups.

9. A compound as claimed in claim 8 , in which MG 1 and MG 2 are selected from the meanings of formulae (V):

C 1 -(Z 1 -C 2 ) a1 -(Z 2 -C 3 ) a2 -(Z 3 -C 4 ) a3   (V)

in which:

C 1 to C 4 are in each case independently optionally-substituted non-aromatic, aromatic, carbocyclic or heterocyclic groups;

Z 1 to Z 3 are independently from each other —COO—, —OCO—, —CH 2 —CH 2 —, —OCH 2 —, —CH 2 O—, —CH═CH—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single bond; and

a1, a2 and a3 are independently integers 0 to 3, such that a1+a2+a3≦3.

10. A compound as claimed in claim 9 , in which C 1 to C 4 are selected from:

with:

L being —CH 3 , —COCH 3 , —NO 2 , —CN, or halogen

u1 being 0, 1, 2, 3,or 4,

u2 being 0, 1, 2, or 3, and

u3 being 0, 1, or 2.

11. A compound as claimed in claim 10 , in which C 1 to C 4 are selected from optionally-substituted cyclohexyl or cyclohexylene, phenyl or phenylene, naphthyl or naphthylene or phenanthryl or phenanthrylene.

12. A compound as claimed in claim 1 , in which A 1 to A 4 are identical.

13. A compound as claimed in claim 1 , in which E 1 and E 2 are identical.

14. A compound as claimed in claim 1 , in which MG 1 and MG 2 are identical.

15. A compound as claimed in claim 1 , in which CG is a chiral group having at least two adjacent chiral centers.

16. A compound as claimed in claim 1 , in which B 1 and B 2 are identical and both consisting of single bonds, oxygen atoms or an optionally-substituted hydrocarbon group of 1 to 3-C atoms.

17. A liquid crystalline material, in the form of a liquid crystalline mixture, (co)polymer, elastomer, polymer gel or polymer network, comprising at least two components, at least one of which is a chiral compound, characterised in that the chiral compound is a compound of formula (I) as claimed in claim 1 .

18. A liquid crystalline material, in the form of a cholesteric mixture, or cholesteric polymer network, comprising at least two components, at least one of which is a chiral compound, characterised in that the chiral compound is a compound of formula (I) as claimed in claim 1 .

19. A cholesteric polymer network obtainable by copolymerisation of an optically active polymerisable mesogenic mixture comprising:

i) at least one chiral or/and achiral nematic polymerisable mixture chosen from chiral and achiral nematic materials;

ii) at least one chiral dopant of formula (I) as claimed in claim 1 ;

iii) an initiator;

iv) optionally a non-mesogenic compound having at least one polymerisable functional group; and

v) optionally a stabilizer.

20. A chiral polymerisable cholesteric mixture, essentially consisting of:

i) 70 to 99% by weight of at least one achiral polymerisable liquid crystal;

ii) 0.1 to 30% by weight of a chiral compound of formula I as claimed in claim 1

iii) 0.1 to 5% by weight of a photoinitiator; and

iv) 0 to 5% of a stabiliser.

21. A cholesteric film obtainable by the steps comprising ordering a chiral polymerisable cholesteric mixture as claimed in claim 20 in the monomeric state and in situ UV polymerisation of the resulting ordered mixture.

22. A compound as claimed in claim 5 , wherein

Sp 5 represents ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, or dodecylene; and

X 4 represents —O—, —COO—, —OCO— or single bond.

23. A compound as claimed in claim 6 , wherein

X 2 to X 3 each independently represent —O—, —COO—, —OCO— or a single bond; and

Sp 2 represents ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene or dodecylene.

24. A cholesteric polymer network as claimed in claim 19 , wherein the non-mesogenic compound having at least one polymerisable functional group is a diacrylate compound.

25. A method which comprises adding a compound as claimed in claim 1 as a dopant to liquid crystals or to a mixture of liquid crystals.

26. A method which comprises ordering a liquid crystalline material as claimed in claim 17 in the monomeric state and in situ UV polymerizing the ordered mixture to produce a polymeric cholesteric layer.

27. A method which comprises ordering a liquid crystalline material as claimed in claim 18 the monomeric state and in situ UV polymerizing the ordered mixture to produce a polymeric cholesteric layer.

28. An optical component comprising a cholesteric polymer network as claimed in claim 19 .

29. An optical component comprising a chiral polymerizable cholesteric mixture as claimed in claim 20 .

30. An optical component comprising a cholesteric film as claimed in claim 21 .