Synthesis of organometallic cyclometallated transition metal complexes

1. A process for forming a tris-cyclometallated complex comprising the step of reacting;

a) an M(I) complex, wherein M represents Rh or Ir, and said complex comprises at least two ligands and contains at least two alkenyl groups pi-bonded to M, wherein the M(I) complex is represented by Formula (1):

[(L 1 ) n M(L 2 ) m ]X  (1)

wherein:

M represents Ir(I) or Rh(I);

each L 1 represents an independently selected ligand comprising an alkenyl group and provided that two L 1 groups may join to form a diene or cyclodiene group;

each L 2 represents an independently selected Lewis base ligand;

n is 2-4;

m is 0-2;

the sum of m and n is 4; and

X represents a counterion with

b) a heterocyclic compound capable of forming a organometallic cyclometallated complex.

2. The process according to claim 1 , wherein M represents Ir.

3. The process according to claim 1 , wherein the two alkenyl groups comprise a cyclodiene group.

4. The process according to claim 3 , wherein the cyclodiene group comprises a 1,5-cyclooctadiene group.

5. The process according to claim 1 , wherein the M(I) complex includes at least four alkenyl groups pi-bonded to M.

6. The process according to claim 5 , wherein the four alkenyl groups comprise two independently selected cyclodiene groups.

7. The process according to claim 1 , wherein the M(I) complex includes two monodentate ligands.

8. The process according to claim 7 , wherein at least one monodentate ligand is coordinated to the metal by means of a nitrogen-metal bond or an oxygen-metal bond.

9. A process according to claim 1 , wherein the heterocyclic compound comprises at least two heteroatoms.

10. A process according to claim 1 , wherein the heterocyclic compound comprises a pyridine group, a quinoline group, an isoquinoline group, a pyrimidine group, an indole group, an indazole group, a thiazole group, an oxazole group, an imidazole group, or a pyrazole group.

11. A process according to claim 1 , wherein the tris-cyclometallated complex formed comprises at least 95% of the facial isomer.

12. A process according to claim 1 , further comprising a diol solvent.

13. A process according to claim 1 , wherein, n is 2, m is 2, and the two L 1 groups join to form a cyclodiene group, each L 2 represents an independently selected monodentate ligand.

14. A process according to claim 1 , wherein n is 4, m is 0 and the L 1 groups join together so as to form two independently selected cyclodiene groups.

15. A process according to claim 1 wherein the heterocycle is represented by Formula (2a):

wherein:

Z a represents the atoms necessary to form a an aromatic ring group; and

R 1 and R 2 represent substituent groups, provided that R 1 and R 2 may form a ring group.

16. A process according to claim 1 wherein the heterocycle is represented by Formula (2b):

wherein:

Z represents the atoms necessary to form a diazole ring group that is fused with at least one aromatic ring group;

N f represents a nitrogen atom at a bridgehead position between the diazole ring group and the fused aromatic ring group; and

R 1 and R 2 represent substituent groups, provided that R 1 and R 2 may form a ring group.

17. A process according to claim 1 wherein the tris-cyclometallated complex is represented by Formula (3b):

wherein:

Z represents the atoms necessary to form a diazole ring group that is fused with at least one aromatic ring group;

N f represents a nitrogen atom at a bridgehead position between the diazole ring group and the fused aromatic ring group;

M′ represents Ir(III) or Rh(III); and

R 1 and R 2 represent substituent groups, provided that R 1 and R 2 may form a ring group.

18. A process according to claim 1 wherein the tris-cyclometallated complex is represented by Formula (3c):

wherein:

Z represents the atoms necessary to form a diazole ring group that is fused with at least one aromatic ring group;

N f represents a nitrogen atom at a bridgehead position between the diazole ring group and the fused aromatic ring group;

M′ represents Ir(III) or Rh(III);

R 1 and R 2 represent substituent groups, provided that R 1 and R 2 may form a ring group;

A represents a substituted or unsubstituted heterocyclic ring group containing at least one nitrogen atom;

B represents a substituted or unsubstituted aromatic or heteroaromatic ring;

m is an integer from 1 to 3; and

n in an integer from 0 to 2 such that m+n=3.

19. A process according to claim 1 wherein the reaction is heated to a temperature in the range of 140-190° C.

20. A process according to claim 1 , wherein, n is 2, m is 2, and the two L 2 groups join to form a neutral bidentate ligand.