Asymmetric dendrimers

1. A light emitting dendrimer having the formula:

CORE−[DENDRITE 1 ] n [DENDRITE 2 ] m

in which CORE represents an atom or group, n and m, which may be the same or different, each represent an integer of at least 1, each DENDRITE 1 , which may be the same or different when n is greater than 1, and each DENDRITE 2 , which may be the same or different when m is greater than 1, represent dendritic structures, at least one of said structures being fully conjugated and comprising aryl and/or heteroaryl groups and, optionally, vinyl and/or acetylenyl groups, connected via sp 2 or sp hybridized carbon atoms of said aryl, heteroaryl, vinyl and acetylenyl groups, and at least one branching point and/or link between the branching points in DENDRITE 1 being different from those in DENDRITE 2 , CORE terminating in the single bond which is connected to a sp 2 hybridized (ring) carbon atom of the first (hetero)aryl group to which more than one conjugated dendritic branch is attached, said ring carbon atom forming part of said fully conjugated DENDRITE 1 or DENDRITE 2 and CORE terminating at the single bond to the first branching point for the other of said DENDRITE 1 or DENDRITE 2 , at least one of the CORE, DENDRITE 1 and DENDRITE 2 being luminescent.

2. A dendrimer according to claim 1 wherein at least one of DENDRITE 1 and DENDRITE 2 comprises aryl-(vinyl) x -[(aryl′)-(vinyl) y ] z -aryl;

or aryl-(acetylenyl) x -[(aryl′)-(acetenyl) y ] z , -aryl;

or aryl- (vinyl) x -(aryl′) z -(acetylenyl) y -aryl

links where x, y and z, which can be the same or different, are integers from 0 to 3, the order of the vinyl, aryl′ and acetylenyl groups can be varied, aryl includes heteroaryl and aryl′ is the same as or different from aryl and said aryl groups are branching points.

3. A dendrimer according to claim 2 , wherein at least one of DENDRITE 1 and DENDRITE 2 comprises aryl-(aryl′) a -aryl links and the other comprises aryl-(vinyl) x -[(aryl′) v -(vinyl) y ] z -aryl links where x is an integer from 1 to 3 and a, y, v and z, which can be the same or different, are integers from 0 to 3, and said aryl groups are branching points.

4. A dendrimer according to claim 2 , wherein at least one of DENDRITE 1 and DENDRITE 2 comprises aryl-(aryl′) a -aryl links where a is an integer from 0 to 3 and the other one of DENDRITE 1 and DENDRITE 2 comprises aryl-(acetylenyl) d -[(aryl′) e -(acetylenyl) f ] g -aryl links where d is an integer from 1 to 3, f is an integer from 0 to 3, and e and g, which can be the same or different, are integers from 0 to 3, and said aryl groups are branching points.

5. A dendrimer according to claim 2 , wherein one of DENDRITE 1 and DENDRITE 2 comprises aryl-(vinyl) x -[(aryl′) v -(vinyl) y ] z -aryl links and the other of DENDRITE 1 and DENDRITE 2 comprises aryl-(acetylenyl) d -[(aryl′) e -(acetylenyl) f ] g -aryl links where d and x, which can be the same or different, are integers from 1 to 3, y and f, which can be the same or different, are integers from 0 to 3, and v, e, z and g, which can be the same or different, are integers from 0 to 3, and said aryl groups are branching points.

6. A dendrimer according to claim 3 , wherein in at least one of DENDRITE 1 and DENDRITE 2 the links between adjacent branching points are not all the same.

7. A dendrimer according to claim 1 , wherein DENDRITE 1 and DENDRITE 2 both represent said fully conjugated structures.

8. A dendrimer according to claim 1 , wherein if DENDRITE 1 differs from DENDRITE 2 merely in a different link then, for two links to be regarded as different one said link must comprise at least one aryl, heteroaryl, vinyl or acetylenyl group which is not present in the other of said two links.

9. A dendrimer according to claim 4 , wherein in at least one of DENDRITE 1 and DENDRITE 2 the links between adjacent branching points are not all the same.

10. A dendrimer according to claim 5 , wherein in at least one of DENDRITE 1 and DENDRITE 2 the links between adjacent branching points are not all the same.

11. A dendrimer according to claim 5 , wherein x and d are 1 and z and g are 0.

12. A dendrimer according claim 1 , wherein at least one of DENDRITE 1 and DENDRITE 2 comprises one or more (hetero)aryl linking groups.

13. A dendrimer according to claim 1 wherein at least one of DENDRITE 1 and DENDRITE 2 does not have an inherently at least partly conjugated molecular structure.

14. A dendrimer according to claim 1 wherein the CORE comprises at least one moiety selected from the group consisting of benzene, pyridine, pyrimidine, triazine, thiophene, fluorene, divinylbenzene, distyrylethylene, divinylpyridine, pyrimidine, triazine, divinylthiophene, oxadiazole, coronene, fluorescent dye compounds, fluorescent marker compounds, organometallic complexes, distyryl anthracene moieties, porphyrin moieties, and distyrylbenzene moieties.

15. A dendrimer according to claim 1 wherein the aryl groups are selected from the group consisting of benzene, pyridine and triazine.

16. A dendrimer according to claim 1 , wherein the dendrimer comprises at least one surface group attached to a distal (hetero)aryl ring carbon of said conjugated dendrite.

17. A dendrimer according to claim 1 , wherein at least one surface group is selected from further-reactable alkenes, (meth)acrylates, sulphur-containing groups, silicon-containing groups; sulphonyl groups; polyether groups; C 1 -to-C 15 alkyl groups; amine groups; mono-C 1 -to-C 15 alkyl amine groups, di-C 1 -to-C 15 alkyl amine groups, tri-C 1 -to-C 15 alkyl amine groups; —COOR groups wherein R is hydrogen or C 1 to C 15 alkyl; —OR groups wherein R is hydrogen, aryl, C 1 -to C 15 alkyl or C 1 -to C 15 alkenyl; —O 2 SR groups wherein R is C 1 -to-C 15 alkyl or C 1 -to C 15 alkenyl; —SR groups wherein R is aryl, C 1 to C 15 alkyl or C 1 -to C 15 alkenyl; —SiR 3 groups wherein the R groups are the same or different and are hydrogen, C 1 to C 15 alkyl or C 1 -to C 15 alkenyl, —SR=groups where R=is aryl, C 1 -to-C 15 alkyl or C 1 -to-C 15 alkenyl, aryl, and heteroaryl.

18. A dendrimer according to claim 1 wherein the surface group is such as to allow processing followed by photopatterning.

19. A light-emitting device which comprises a dendrimer as claimed in claim 1 .

20. A light emitting device in which a light emitting element is a dendrimer as claimed in claim 1 .

21. A light emitting dendrimer having the formula:

CORE−[DENDRITE] n

in which CORE represents an atom or group, n represents an integer of at least 1, each DENDRITE, which may be the same or different, represents an inherently at least partially conjugated dendritic molecular structure which comprises aryl and/or heteroaryl and, optionally, vinyl and/or acetylenyl groups, connected via sp 2 or sp hybridized carbon atoms of said aryl, heteroaryl, vinyl and acetylenyl groups, and wherein the links between at least one pair of adjacent branching points in said DENDRITE are different such that if two links are to be regarded as different then one said link must comprise at least one aryl, heteroaryl, vinyl or acetylenyl group which is not present in the other of said two links, CORE terminating in the single bond which is connected to a sp 2 hybridized (ring) carbon atom of the first (hetero)aryl group to which more than one dendritic branch is attached, said ring carbon atom forming part of said DENDRITE, at least one of the CORE and the DENDRITE being luminescent.

22. A dendrimer according to claim 21 , wherein the different types of links are selected from aryl-(aryl) a -aryl, aryl-(vinyl) x -[(aryl′) v -(vinyl) y ] z -aryl, and aryl (acetylenyl) d -[(aryl′) e -(acetylenyl) f ] g -aryl, where x and d, which can be the same or different, are integers from 1 to 3, y and f, which can be the same or different, are integers from 0 to 3, and a, g, z, e and v, which can be the same or different, are integers from 0 to 3, said aryl groups being branching points.

23. A dendrimer according to claim 22 , wherein a is 0 or 1, x and d are 1, and z and g are 0.

24. A dendrimer according to claim 21 , wherein DENDRITE comprises one or more (hetero)aryl linking groups.

25. A dendrimer according to claim 21 which comprises at least one DENDRITE, which does not have an inherently at least partly conjugated molecular structure.

26. A dendrimer according to claim 21 wherein the CORE comprises at least one moiety selected from the group consisting of benzene, pyridine, pyrimidine, triazine, thiophene, fluorene, divinylbenzene, distyrylethylene, divinylpyridine, pyrimidine, triazine, divinylthiophene, oxadiazole, coronene, fluorescent dye compounds, fluorescent marker compounds, organometallic complexes, distyryl anthracene moieties, porphyrin moieties, and distyrylbenzene moieties.

27. A dendrimer according to claim 21 wherein the aryl groups are selected from the group consisting of benzene, pyridine and triazine.

28. A dendrimer according to claim 21 , wherein the dendrimer comprises at least one surface group attached to a distal (hetero)aryl ring carbon of said conjugated dendrite.

29. A dendrimer according to claim 28 , wherein at least one surface group is selected from further-reactable alkenes, (meth)acrylates, sulphur-containing groups, silicon-containing groups; sulphonyl groups; polyether groups; C 1 -to-C 15 alkyl groups; amine groups; mono-C 1 -to-C 15 alkyl amine groups, di-C 1 -to-C 15 alkyl amine groups, tri-C 1 -to-C 15 alkyl amine groups; —COOR groups wherein R is hydrogen or C 1 to C 15 alkyl; —OR groups wherein R is hydrogen, aryl, C 1 -to C 15 alkyl or C 1 -to C 15 alkenyl; —O 2 SR groups wherein R is C 1 -to-C 15 alkyl or C 1 -to C 15 alkenyl; —SR groups wherein R is aryl, C 1 to C 15 alkyl or C 1 -to C 15 alkenyl; —SiR 3 groups wherein the R groups are the same or different and are hydrogen, C 1 to C 15 alkyl or C 1 -to C 15 alkenyl, —SR=groups where R=is aryl, C 1 -to-C 15 alkyl or C 1 -to-C 15 alkenyl, aryl, and heteroaryl.

30. A dendrimer according to claim 29 wherein the surface group is such as to allow processing followed by photopatterning.

31. A light-emitting device which comprises a dendrimer as claimed in claim 21 .

32. A light emitting device in which a light emitting element is a dendrimer as claimed in claim 21 .