Carbene metal complexes as OLED materials

1. An organic light emitting device, comprising:

(a) an anode;

(b) a cathode;

(c) an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a compound having one or more carbene ligands coordinated to a metal center, and wherein the compound has the structure:

wherein M is a metal;

ring D is an aromatic cyclic, heterocyclic, fused cyclic, or fused heterocyclic ring; A is C, N, or P; wherein ring D can be optionally substituted with one or more substituents R 2 ; and

R 1 and R 2 are independently selected from hydrogen, alkyl, alkenyl, alkynyl, aralkyl, CN, CF 3 , CO 2 R′, C(O)R′, C(O)NR′ 2 , NR′ 2 , NO 2 , OR′, SR′, SO 2 , SOR′, SO 3 R′, halo, aryl, heteroaryl, substituted aryl, substituted heteroaryl, or a heterocyclic group; R 3 is independently selected from hydrogen, alkyl, alkenyl, alkynyl, aralkyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, or a heterocyclic group; and additionally or alternatively, two R groups on the same or adjacent ring, together form a 5 or 6-member cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; and wherein said cyclic group is optionally substituted by one or more substituents J;

each substituent J is independently selected from the group consisting of R′, CN, CF 3 , C(O)OR′, C(O)R′, C(O)NR′ 2 , NR′ 2 , NO 2 , OR′, SR′, SO 2 , SOR′, or SO 3 R′, and additionally, or alternatively, two J groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group;

each R′ is independently selected from halo, H, alkyl, alkenyl, alkynyl, heteroalkyl, aralkyl, aryl, and heteroaryl;

α is 0, 1, 2, 3, or 4; c is 0, 1, or 2;

(X-Y) is a photoactive ligand or an ancillary ligand; m is a value from 1 to the maximum number of ligands that may be attached to metal M; and m+n is the maximum number of ligands that may be attached to metal M.

2. The device of claim 1 , wherein the compound is selected from the group consisting of:

3. The device of claim 2 , wherein the compound has the structure:

4. The device of claim 3 , wherein M is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Ru, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Al, Ga, Au, and Ag.

5. The device of claim 4 , wherein M is Ir.

6. The device of claim 5 , wherein m is 3 and n is 0.

7. An organic light emitting device, comprising:

(d) an anode;

(e) a cathode;

(f) an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a carbene ligand coordinated to a metal center, wherein the carbene ligand has the structure;

wherein ring D is an aromatic cyclic, heterocyclic, fused cyclic, or fused heterocyclic ring;

wherein ring D can be optionally substituted with one or more substituents R 2 ; and

R 1 and R 2 are independently selected from hydrogen, alkyl, alkenyl, alkynyl, aralkyl, CN, CF 3 , CO 2 R′, C(O)R′, C(O)NR′ 2 , NR′ 2 , NO 2 , OR′, SR′, SO 2 , SOR′, SO 3 R′, halo, aryl, heteroaryl, substituted aryl, substituted heteroaryl, or a heterocyclic group; R 3 is independently selected from hydrogen, alkyl, alkenyl, alkynyl, aralkyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, or a heterocyclic group; and additionally or alternatively, two R groups on the same or adjacent ring, together form a 5 or 6-member cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; and wherein said cyclic group is optionally substituted by one or more substituents J;

each substituent J is independently selected from the group consisting of R′, CN, CF 3 , C(O)OR′, C(O)R′, C(O)NR′ 2 , NR′ 2 , NO 2 , OR′, SR′, SO 2 , SOR′, or SO 3 R′, and additionally, or alternatively, two J groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group;

each R′ is independently selected from halo, H, alkyl, alkenyl, alkynyl, heteroalkyl, aralkyl, aryl, and heteroaryl;

α is 0, 1, 2, 3, or 4; c is 0, 1, or 2; and A is C, N, or P.

8. The device of claim 7 , wherein the ligand is selected from the group consisting of:

9. The device of claim 8 , wherein the ligand has the structure:

10. A compound comprising one or more carbene ligands coordinated to a metal center, wherein the compound has the structure:

wherein M is a metal;

ring D is an aromatic cyclic, heterocyclic, fused cyclic, or fused heterocyclic ring; A is C, N, or P; wherein ring D can be optionally substituted with one or more substituents R 2 ; and

R 1 and R 2 are independently selected from hydrogen, alkyl, alkenyl, alkynyl, aralkyl, CN, CF 3 , CO 2 R′, C(O)R′, C(O)NR′ 2 , NR′ 2 , NO 2 , OR′, SR′, SO 2 , SOR′, SO 3 R′, halo, aryl, heteroaryl, substituted aryl, substituted heteroaryl, or a heterocyclic group; it is independently selected from hydrogen, alkyl, alkenyl, alkynyl, aralkyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, or a heterocyclic group; and additionally or alternatively, two R groups on the same or adjacent ring, together form a 5 or 6-member cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; and wherein said cyclic group is optionally substituted by one or more substituents J;

each substituent J is independently selected from the group consisting of R′, CN, CF 3 , C(O)OR′, C(O)R′, C(O)NR′ 2 , NR′ 2 , NO 2 , OR′, SR′, SO 2 , SOR′, or SO 3 R′, and additionally, or alternatively, two J groups on adjacent ring atoms form a fused 5- or 6-membered aromatic group;

each R′ is independently selected from halo, H, alkyl, alkenyl, alkynyl, heteroalkyl, aralkyl, aryl, and heteroaryl;

α is 0, 1, 2, 3, or 4; c is 0, 1, or 2;

(X-Y) is a photoactive ligand or an ancillary ligand; m is a value from 1 to the maximum number of ligands that may be attached to metal M; and m+n is the maximum number of ligands that may be attached to metal M.

11. The compound of claim 10 , selected from the group consisting of:

12. The compound of claim 11 , selected from the group consisting of:

13. The compound of claim 12 , wherein M is selected from the group consisting of Ir, Pt, Pd, Rh, Re, Ru, Os, Tl, Pb, Bi, In, Sn, Sb, Te, Al, Ga, Au, and Ag.

14. The compound of claim 13 , wherein M is Ir.

15. The compound of claim 14 , wherein m is 3 and n is 0.