Organic electroluminescent materials and devices

1. A compound represented by Formula I:

wherein rings A 1 , A 2 , A 3 , A 4 , and A 5 each independently represent a five- or six-membered aromatic ring and fuse to each other on the adjacent rings;

wherein rings A 1 , A 2 , A 3 , A 4 , and A 5 are each independently optionally further substituted by one or more substituents selected from the group consisting of 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 X is selected from the group consisting of BR, CRR′, SiRR′, NR, PR, O, S, and Se;

wherein when X is BR, SiRR′, NR, or PR, R and R′ 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 when X is CRR′, R and R′ are each independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and

wherein any adjacent substituents in the compound are optionally joined or fused into a ring.

2. The compound of claim 1 , wherein at least one of A 1 , A 2 , A 3 , A 4 , and A 5 is a five-membered aromatic ring.

3. The compound of claim 1 , wherein at least two of A 1 , A 2 , A 3 , A 4 , and A 5 are five-membered aromatic rings.

4. The compound of claim 1 , wherein two of A 1 , A 2 , A 3 , A 4 , and A 5 are five-membered aromatic rings, and the other three of A 1 , A 2 , A 3 , A 4 , and A 5 are six-membered aromatic rings.

5. The compound of claim 1 , wherein A 2 and A 4 are five-membered aromatic rings, and A 1 , A 3 , and A 5 are six-membered aromatic rings.

6. The compound of claim 1 , wherein at least one of A 1 , A 2 , A 3 , A 4 , and A 5 is a six-membered heteroaryl ring.

7. The compound of claim 1 , wherein X is selected from the group consisting of BR, NR, and PR.

8. The compound of claim 1 , wherein X is selected from the group consisting of CRR′, and SiRR′.

9. The compound of claim 1 , wherein X is selected from the group consisting of O, S, and Se.

10. The compound of claim 1 , wherein X is NR, and R is an electron accepting group.

11. The compound of claim 1 , wherein the compound is represented by one of Formula 1a to Formula 1m:

wherein each of X′ to X 10 is independently selected from the group consisting of N and CR″;

wherein each of R 1 , R 2 , R 3 , R 4 , and R″ is 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 any adjacent substituents are optionally joined or fused into a ring.

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

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

an anode;

a cathode; and

an organic layer, disposed between the anode and the cathode, comprising a compound represented by Formula I:

wherein rings A 1 , A 2 , A 3 , A 4 , and A 5 each independently represent a five- or six-membered aromatic ring and fuse to each other on the adjacent rings;

wherein rings A 1 , A 2 , A 3 , A 4 , and A 5 are each independently optionally further substituted by one or more sub stituents selected from the group consisting of 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 X is selected from the group consisting of BR, CRR′, SiRR′, NR, PR, O, S, and Se;

wherein when X is BR, SiRR′, NR, or PR, R and R′ 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 when X is CRR′, R and R′ are each independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and

wherein any adjacent substituents in the compound are optionally joined or fused into a ring.

14. The OLED of claim 13 , wherein the organic layer is an emissive layer and the compound of Formula I is a host.

15. The OLED of claim 13 , wherein the organic layer further comprises a phosphorescent emissive dopant; wherein the emissive dopant is a transition metal complex having at least one ligand or part of the ligand if the ligand is more than bidentate selected from the group consisting of:

wherein each of X 1 to X 13 is independently selected from the group consisting of carbon and nitrogen;

wherein X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═ 0 , S═O, SO 2 , CR′R″, SiR′R″, and GeR′R″;

wherein R′ and R″ are optionally fused or joined to form a ring;

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

wherein R′, R″, R a , R b , R c , and R d 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; and

wherein any two adjacent substituents of R a , R b , R c , and R d are optionally fused or joined to form a ring or form a multidentate ligand.

16. The OLED of claim 13 , wherein the organic layer is a blocking layer and the compound of Formula I is a blocking material in the organic layer, or wherein the organic layer is a transporting layer and the compound of Formula I is a transporting material in the organic layer.

17. 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.

18. The OLED of claim 13 , wherein the organic layer is an emissive layer and the compound of Formula I is an emitter.

19. The OLED of claim 18 , wherein the OLED emits a luminescent radiation at room temperature when a voltage is applied across the organic light emitting device, and wherein the luminescent radiation comprises a delayed fluorescence process.

20. A formulation comprising a compound according to claim 1 .