Heteroleptic iridium complexes as dopants

1. A compound having the formula:

wherein the number of carbon atoms in R 1 is at least 2;

wherein R 1 is alkyl and R 2 is hydrogen;

wherein R 3 , R 4 , R 5 , R 6 are optionally linked;

wherein R a and R b represent mono-, di-, tri- or tetra-substitution;

wherein X is selected from the group consisting of PR, C═O, S═O, SO 2 , CRR′, SiRR′ and GeRR′;

wherein R a , R b , R, R′, R 3 , R 4 , R 5 , and R 6 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein n is 1 or 2.

2. The compound of claim 1 , wherein n is 2.

3. The compound of claim 1 , wherein R 1 is selected from the group consisting of branched alkyl, cyclic alkyl, bicyclic alkyl, and multicyclic alkyl.

4. The compound of claim 1 , wherein R 1 contains one or more deuterium atoms.

5. The compound of claim 1 , wherein R 3 , R 4 , R 5 and R 6 are independently selected from the group consisting of hydrogen, deuterium, alkyl, aryl, and combinations thereof.

6. The compound of claim 1 , wherein at least one of R 3 , R 4 , R 5 and R 6 comprises a branched alkyl, cyclic alkyl, bicyclic alkyl, or a multicyclic alkyl.

7. The compound of claim 1 , wherein R 3 , R 4 , R 5 or R 6 contain one or more deuterium atoms.

8. A first device comprising a first organic light emitting device, comprising:

an anode;

a cathode; and

an organic layer, disposed between the anode and the cathode, comprising a compound having the formula:

wherein the number of carbon atoms in R 1 is at least 2;

wherein R 1 is alkyl and R 2 is hydrogen;

wherein R 3 , R 4 , R 5 , R 6 are optionally linked;

wherein R a and R b represent mono-, di-, tri- or tetra-substitution;

wherein X is selected from the group consisting of PR, C═O, S═O, SO 2 , CRR′, SiRR′ and GeRR′;

wherein R a , R b , R, R′, R 3 , R 4 , R 5 , and R 6 are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and wherein n is 1 or 2.

9. The first device of claim 8 , wherein the first device is a consumer product.

10. The first device of claim 8 , wherein the first device comprises a lighting panel.

11. The first device of claim 8 , wherein the organic layer is an emissive layer and the compound is an emissive dopant.

12. The first device of claim 8 , wherein the organic layer is an emissive layer and the compound is a non-emissive dopant.

13. The first device of claim 8 , wherein the organic layer further comprises a host.

14. The first device of claim 13 , wherein the host comprises a triphenylene containing benzo-fused thiophene or benzo-fused furan;

wherein any substituent in the host is an unfused substituent independently selected from the group consisting of C n H 2n+1 , OC n H 2n+1 , OAr 1 , N(C n H 2n+1 ) 2 , N(Ar 1 )(Ar 2 ), CH═CH—C n+1 , C≡CC n H 2n+1 , Ar 1 , Ar 1 —Ar 2 , and C n H 2n —Ar 1 ;

wherein n is from 1 to 10; and

wherein Ar 1 and Ar 2 are independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof.

15. The first device of claim 14 , wherein the host has the formula:

16. The first device of claim 13 , wherein the host is selected from the group consisting of:

and combinations thereof.

17. The first device of claim 13 , wherein the host is a metal complex.