Organic electroluminescent materials and devices

1. A compound comprising a ligand L selected from the group A consisting of:

wherein X 7 is Z 2 ; and

wherein X 9 is Z 2 ;

wherein each X 1 , X 3 , X 4 , and X 5 are carbon, and X 2 , and X 6 to X 11 are independently selected from carbon or nitrogen;

wherein each R a , R b , and R c may represent from mono substitution to the possible maximum number of substitution, or no substitution;

wherein each R a , R b , and R c 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; wherein when R a , R b , and R c represent at least di substitution, each of the two adjacent R a , two adjacent R b , and two adjacent R c are optionally fused or joined to form a ring;

wherein the ligand L is coordinated to a metal M selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Au, and Cu;

wherein the ligand L is optionally linked to provide a tridentate, or tetradentate-ligand;

wherein the compound comprises at least one intramolecular hydrogen bonding interaction as shown

Z 1 —H----Z 2

wherein Z 1 is carbon of alkyl, and Z 2 is nitrogen

and

the proton NMR chemical shift of H is shifted downfield by at least 1.3 ppm compared to the compound when Z 2 is carbon.

2. The compound of claim 1 , wherein the compound has an emission with the first peak wavelength at the high energy end smaller at room temperature than that at 77K.

3. The compound of claim 1 , wherein M is Ir or Pt.

4. The compound of claim 1 , wherein the compound has a formula of Ir(L) n (L′) 3-n ;

wherein L′ is selected from group A; and

wherein n is 1, 2, or 3.

5. The compound of claim 1 , wherein the compound has a formula of Pt(L) m (L′) 2-m ;

wherein L′ is selected from group A; and

wherein m is 1 or 2.

6. The compound of claim 1 , wherein the ligand L is selected from the group consisting of:

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

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

an anode;

a cathode; and

an organic layer, disposed between the anode and the cathode, comprising a compound comprising a ligand L of claim 1 .

9. The first device of claim 8 , wherein the first device is selected from the group consisting of a consumer product, an electronic component module, an organic light-emitting device, and a lighting panel.

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

11. The first device of claim 8 , 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 , C n H 2n —Ar 1 , or 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.

12. The first device of claim 8 , 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.

13. The first device of claim 8 , wherein the organic layer further comprises a host and the host is selected from the group consisting of:

and combinations thereof.

14. The compound of claim 1 , wherein X 5 , X 6 , and X 8 are carbon, and are each substituted with R b , wherein R b is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, aryl, and heteroaryl.

15. The compound of claim 14 , wherein X 6 and X 9 are Z 2 .

16. The compound of claim 1 , wherein X 6 , X 7 , and X 9 are carbon, and are each substituted with R c , wherein R c is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, aryl, and heteroaryl.

17. The compound of claim 16 , wherein X 5 and X 8 are Z 2 .