Organic electroluminescent materials and devices

1. A compound of Formula II

wherein R has the following structure and is fused to ring A:

Z 1 to Z 8 is independently selected from nitrogen or carbon;

and the wave lines indicate the bonds to two of the adjacent Z 1 to Z 4 of ring A;

wherein when two of the adjacent Z 1 to Z 4 are used to fuse to R, those two of the adjacent Z 1 to Z 4 are carbon;

R 1 and R 4 independently represent mono, di, tri, or tetra substitutions, or no substitution;

R 2 and R 3 independently represent mono, or di substitutions, or no substitution;

R 7 and R 8 independently represent mono, di, tri, or tetra substitutions, or no substitution;

wherein X is O or S;

wherein R 1 , R 2 , R 3 , R 4 , R 7 , and R 8 are each 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;

wherein any two adjacent substituents R 1 , R 2 , R 3 , R 4 , R 7 , and R 8 are optionally joined to form a ring, which can be further substituted;

wherein R 5 and R 6 are independently branched alkyl which is partially deuterated, or linear alkyl which is partially deuterated; or

R 5 and R 6 are alkyl and together join to form a ring which is substituted with hydrogen, deuterium, alkyl, cycloalkyl, or combinations thereof.

2. The compound of claim 1 , wherein each of Z 1 to Z 4 is carbon.

3. The compound of claim 1 , wherein each of Z 5 to Z 8 is carbon.

4. The compound of claim 1 , wherein each of Z 1 to Z 8 is carbon.

5. The compound of claim 1 , wherein at least one of Z 5 to Z 8 is nitrogen.

6. The compound of claim 1 , wherein X is O.

7. The compound of claim 1 , wherein R 5 and R 6 are alkyl and together join to form a ring which is substituted with hydrogen, deuterium, alkyl, cycloalkyl, or combinations thereof.

8. The compound of claim 1 , wherein the Formula II includes a ligand L A selected from the group consisting of:

9. The compound of claim 1 , wherein the Formula II includes a ligand L B selected from the group consisting of:

10. The compound of claim 8 , wherein the compound has the formula Ir(L A )(L B ) 2 ;

wherein L B is selected from the group consisting of:

11. The compound of claim 1 , wherein R 5 and R 6 are independently branched alkyl which is partially deuterated.

12. The compound of claim 1 , wherein R 5 and R 6 are independently linear alkyl which is partially deuterated.

13. An organic light emitting device (OLED) comprising:

an anode;

a cathode; and

an organic layer disposed between the anode and the cathode, the organic layer comprising a compound of Formula II

wherein R has the following structure and is fused to ring A:

Z 1 to Z 8 is independently selected from nitrogen or carbon;

and the wave lines indicate the bonds to two of the adjacent Z 1 to Z 4 of ring A;

wherein when two of the adjacent Z 1 to Z 4 are used to fuse to R, those two of the adjacent Z 1 to Z 4 are carbon;

R 1 and R 4 independently represent mono, di, tri, or tetra substitutions, or no substitution;

R 2 and R 3 independently represent mono, or di substitutions, or no substitution;

R 7 and R 8 independently represent mono, di, tri, or tetra substitutions, or no substitution;

wherein X is O or S;

wherein R 1 , R 2 , R 3 , R 4 , R 7 , and R 8 are each 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;

wherein any two adjacent substituents R 1 , R 2 , R 3 , R 4 , R 7 , and R 8 are optionally joined to form a ring, which can be further substituted;

wherein R 5 and R 6 are independently branched alkyl which is partially deuterated, or linear alkyl which is partially deuterated; or

R 5 and R 6 are alkyl and together join to form a ring which is substituted with hydrogen, deuterium, alkyl, cycloalkyl, or combinations thereof.

14. The OLED of claim 13 , wherein the OLED is incorporated into a device selected from the group consisting of a consumer product, an electronic component module, and a lighting panel.

15. The OLED of claim 13 , wherein the organic layer is an emissive layer and the compound is an emissive dopant or a non-emissive dopant.

16. The OLED of claim 13 , wherein the organic layer further comprises a host; 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 H 2n+1 , C≡CC n H 2n+1 , Ar 1 , Ar 1 -Ar 2 , and C n H 2n —Ar 1 , or the host has no substitution;

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.

17. The OLED of claim 13 , wherein the organic layer further comprises a host, wherein the host comprises at least one chemical group selected from the group consisting of triphenylene, carbazole, dibenzothiphene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.

18. The OLED of claim 13 , wherein the organic layer further comprises a host and the host is selected from the group consisting of:

and combinations thereof.

19. A formulation comprising a compound of Formula II

wherein R has the following structure and is fused to ring A:

Z 1 to Z 8 is independently selected from nitrogen or carbon;

and the wave lines indicate the bonds to two of the adjacent Z 1 to Z 4 of ring A;

wherein when two of the adjacent Z 1 to Z 4 are used to fuse to R, those two of the adjacent Z 1 to Z 4 are carbon;

R 1 and R 4 independently represent mono, di, tri, or tetra substitutions, or no substitution;

R 2 and R 3 independently represent mono, or di substitutions, or no substitution;

R 7 and R 8 independently represent mono, di, tri, or tetra substitutions, or no substitution;

wherein X is O or S;

wherein R 1 , R 2 , R 3 , R 4 , R 7 , and R 8 are each 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;

wherein any two adjacent substituents R 1 , R 2 , R 3 , R 4 , R 7 , and R 8 are optionally joined to form a ring, which can be further substituted;

wherein R 5 and R 6 are independently branched alkyl which is partially deuterated, or linear alkyl which is partially deuterated; or

R 5 and R 6 are alkyl and together join to form a ring which is substituted with hydrogen, deuterium, alkyl, cycloalkyl, or combinations thereof.