Organic electroluminescent materials and devices

1. A compound of Formula I

wherein

X 1 to X 8 are independently selected from C or N; wherein no more than two of X 1 to X 4 represent N, and no more than two of X 5 to X 8 represent N;

Y is NR 2 ;

R A and R B represent mono to the maximum allowable substitution, or no substitution; and

each R A , R B , R 1 , R 2 , R 3 , and R 4 are independently hydrogen or a substituent 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; or optionally, two adjacent substituents of R A and/or R B can join to form a ring;

wherein R 1 comprises a structure selected from the group consisting of formula A, formula B, and formula C

wherein

Z is selected from the group consisting of NR 5 , O, S, Se, and CR 6 R 7 ; wherein R 5 is an aromatic linker selected from phenyl, naphthyl, or an aza-analog thereof; each R 6 and R 7 is independently a substituent selected from the group consisting of deuterium, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof, or optionally, R 6 or R 7 is an aromatic linker that connects the structure of formula A to Formula I, or the structure of formula C to Formula I; X 9 to X 41 are independently selected from C or N; wherein in the structure of formula B, at least one of X 17 to X 33 is N; and in the structure of formula C, at least one of X 34 to X 41 is N; wherein no more than two of X 9 to X 12 represent N, no more than two of X 13 to X 16 represent N, no more than two of X 17 to X 20 represent N, no more than two of X 21 to X 24 represent N, no more than two of X 25 to X 28 represent N, no more than two of X 29 to X 33 represent N, no more than two of X 34 to X 37 represent N, and no more than two of X 38 to X 41 represent N;

R C , R D , R E , R F , R G , R H , R I , and R J represent mono to the maximum allowable substitution, or no substitution;

R A , R B , R C , R D , R E , R F , R G , R H , R I , and R J represent nothing for ring atoms with fully filled valencies; and

each R C , R D , R E , R F , R G , R H , R I , and R J are independently hydrogen or a substituent 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.

2. The compound of claim 1 , wherein each R A , R B , R 1 , R 2 , R 3 , R 4 , and R C , R D , R E , R F , R G , R H , R I , and R J , are independently hydrogen or a substituent selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof.

3. The compound of claim 1 , wherein the substituent R 1 comprises the structure of the formula B.

4. The compound of claim 1 , wherein each of X 1 to X 8 is C, or one of X 1 to X 8 is N.

5. The compound of claim 1 , wherein Z is NR 5 , wherein R 5 is a substituent selected from the group consisting of deuterium, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof; and the structure selected from the group consisting of the formula A, the formula B, and the formula C connects to Formula I by one of R C to R J .

6. The compound of claim 1 , wherein at least one of R A , R B , R 1 , R 2 , R 3 , or R 4 comprises a structure selected from the group consisting of formula A and formula B;

wherein in the structure of formula A, one of X 9 to X 16 is N; and

wherein in the structure of formula B, at least two of X 17 to X 33 is N.

7. A compound selected from the group consisting of:

8. An organic light emitting device (OLED) that includes an anode, a cathode, and

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

wherein

X 1 to X 8 are independently selected from C or N; wherein no more than two of X 1 to X 4 represent N, and no more than two of X 5 to X 8 represent N;

Y is NR 2 ;

R A and R B represent mono to the maximum allowable substitution, or no substitution; and

each R A , R B , R 1 , R 2 , R 3 , and R 4 are independently hydrogen or a substituent 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; or optionally, two adjacent substituents of R A and/or R B can join to form a ring;

wherein R 1 comprises a structure selected from the group consisting of formula A, formula B, and formula C

wherein

Z is selected from the group consisting of NR 5 , O, S, Se, and CR 6 R 7 ; wherein R 5 is an aromatic linker selected from phenyl, naphthyl, or an aza-analog thereof; each R 6 and R 7 is independently a substituent selected from the group consisting of deuterium, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof, or optionally, R 6 or R 7 is an aromatic linker that connects the structure of formula A to Formula I, or the structure of formula C to Formula I;

X 9 to X 41 are independently selected from C or N; wherein in the structure of formula B, at least one of X 17 to X 33 is N; and in the structure of formula C, at least one of X 34 to X 41 is N; wherein no more than two of X 9 to X 12 represent N, no more than two of X 13 to X 16 represent N, no more than two of X 17 to X 20 represent N, no more than two of X 21 to X 24 represent N, no more than two of X 25 to X 28 represent N, no more than two of X 29 to X 33 represent N, no more than two of X 34 to X 37 represent N, and no more than two of X 38 to X 41 represent N;

R C , R D , R E , R F , R G , R H , R I , and R J represent mono to the maximum allowable substitution, or no substitution;

R A , R B , R C , R D , R E , R F , R G , R H , R I , and R J represent nothing for ring atoms with fully filled valencies; and

each R C , R D , R E , R F , R G , R H , R I , and R J are independently hydrogen or a substituent 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.

9. The OLED of claim 8 , wherein the organic layer is an emissive layer and the compound of Formula I is a host.

10. The OLED of claim 9 , 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

Y 1 to Y 13 are independently selected from the group consisting of carbon and nitrogen;

Y′ is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO 2 , CR′R″, SiR′R″, and GeR′R″; and R′ and R″ are optionally fused or joined to form a ring;

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

each 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; or optionally, any two adjacent substitutents of R a , R b , R c , and R d join to form a ring or form a multidentate ligand.

11. The OLED of claim 8 , wherein the compound of Formula I is a first host compound and a second host compound is selected from the group consisting of

12. The OLED of claim 8 , wherein the organic layer is a blocking layer and the compound of Formula I is a blocking material in the organic layer.

13. The OLED of claim 8 , wherein the organic layer is a transporting layer and the compound of Formula I is a transporting material in the organic layer.

14. A consumer product that includes the OLED of claim 8 ;

wherein the consumer product is selected from the group consisting of a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a laser printer, a telephone, a cell phone, tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display that is less than 2 inches diagonal, a 3-D display, a virtual reality or augmented reality display, a vehicle, a video walls comprising multiple displays tiled together, a theater or stadium screen, a light therapy device, and a sign.

15. A formulation comprising a compound of Formula I in accordance with claim 1 .

16. An organic light emitting device (OLED) that includes an anode, a cathode, and

an organic layer disposed between the anode and the cathode, the organic layer comprising the compound of claim 7 .