Organic Electroluminescent Materials and Devices

1 . A compound having a formula selected from the group consisting of:

wherein R is selected from the group consisting of:

wherein R 4 is selected from the group consisting of alkyl, alkoxy, silane, aryl, heteroaryl, and combinations thereof;

wherein R 1 , R 2 and R 3 each independently represents mono to maximum allowable substitutions, or no substitution;

wherein R 1 , R 2 and R 3 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, alkene, alkyne, alkoxy, halogen, silane, nitrile, nitro, aryl, heteroaryl and combinations thereof;

wherein any two adjacent substituents are optionally joined or fused into a ring;

wherein R 4 , R 1 , R 2 , and R 3 are each independently, optionally, further substituted with one or more substituents selected from the group consisting of hydrogen, deuterium, alkyl, alkene, alkyne, alkoxy, halogen, silane, nitrile, nitro, aryl, heteroaryl, and combinations thereof; and

wherein any hydrogen in the compound is optionally replaced with deuterium.

2 . The compound of claim 1 , wherein the formula is Formula I.

3 . The compound of claim 1 , wherein the formula is Formula II.

4 . The compound of claim 1 , wherein R 1 , R 2 and R 3 are each a hydrogen.

5 . The compound of claim 1 , wherein R 4 is selected from the group consisting of

and combinations thereof,

wherein X is selected from a group consisting of O, S and Se.

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

7 . 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 having a formula selected from the group consisting of:

wherein R is selected from the group consisting of:

wherein R 4 is selected from the group consisting of alkyl, alkoxy, silane, aryl, heteroaryl, and combinations thereof;

wherein R 1 , R 2 and R 3 each independently represents mono to maximum allowable substitutions, or no substitution;

wherein R 1 , R 2 and R 3 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, alkene, alkyne, alkoxy, halogen, silane, nitrile, nitro, aryl , heteroaryl and combinations thereof;

wherein any two adjacent substituents are optionally joined or fused into a ring;

wherein R 4 , R 1 , R 2 , and R 3 are each independently, optionally, further substituted with one or more substituents selected from the group consisting of hydrogen, deuterium, alkyl, alkene, alkyne, alkoxy, halogen, silane, nitrile, nitro, aryl , heteroaryl, and combinations thereof; and

wherein any hydrogen in the compound is optionally replaced with deuterium.

8 . The OLED of claim 7 , wherein the organic layer is an emissive layer and the compound of Formula I, or II is a host.

9 . The OLED of claim 7 , 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 X 1 to X 13 are 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═O, 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 R a , R b , R c , and R d may represent from mono substitution to the possible maximum number of substitution, or no substitution;

wherein R′, R″, R a , R b , R e , 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.

10 . The OLED of claim 7 , wherein the organic layer is a blocking layer and the compound of Formula I, or II is a blocking material in the organic layer.

11 . The OLED of claim 7 , wherein the organic layer is a transporting layer and the compound of Formula I, or II is a transporting material in the organic layer.

12 . The OLED of claim 7 , 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.

13 . A formulation comprising a compound having a formula selected from the group consisting of:

wherein R is selected from the group consisting of:

wherein R 4 is selected from the group consisting of alkyl, alkoxy, silane, aryl, heteroaryl, and combinations thereof;

wherein R 1 , R 2 and R 3 each independently represents mono to maximum allowable substitutions, or no substitution;

wherein R 1 , R 2 and R 3 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, alkene, alkyne, alkoxy, halogen, silane, nitrile, nitro, aryl , heteroaryl and combinations thereof;

wherein any two adjacent substituents are optionally joint or fused into a ring;

wherein R 4 , R 1 , R 2 , and R 3 are each independently, optionally, further substituted with one or more substituents selected from the group consisting of hydrogen, deuterium, alkyl, alkene, alkyne, alkoxy, halogen, silane, nitrile, nitro, aryl, heteroaryl, and combinations thereof; and

wherein any hydrogen in the compound is optionally replaced with deuterium.