Organic Electroluminescent Materials and Devices

1 .- 37 . (canceled)

38 . A compound of Formula I:

wherein:

ring B is a 5-membered heterocyclic ring, or a 6-membered carbocyclic ring;

each of X 1 and X 2 is independently C, CR, or N, with at least one of them being C;

each of X 3 -X 11 is independently C, CR, or N, with at least one of them being N, and two adjacent of X 3 -X 7 are carbon-fused to the shown moiety through the linkage indicated by the two squiggly lines;

Y is selected from the group consisting of O, S, Se, NR′, CR′R″, and SiR′R″;

each of R A and R B independently represents zero, mono, or up to a maximum allowed substitution to its associated ring;

each of R, R′, R″, R″, R A , and R B is independently a hydrogen or a substituent selected from the group consisting of —SiR 1 R 2 R 3 or —GeR 1 R 2 R 3 , deuterium, halogen, alkyl, partially or fully deuterated alkyl, cycloalkyl, partially or fully deuterated cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, partially or fully deuterated aryl, heteroaryl, partially or fully deuterated heteroaryl, nitrile, and combinations thereof, with at least one of R A or R B comprising —SiR 1 R 2 R 3 or —GeR 1 R 2 R 3 ;

each of R 1 , R 2 , and R 3 is independently selected from the group consisting of alkyl, aryl group, heteroaryl group, and combinations thereof; and

any two substituents are optionally joined or fused to form a ring.

39 . The compound of claim 38 , wherein each of R, R′, R″, R A , and R B is independently a hydrogen or a substituent selected from the group consisting of —SiR 1 R 2 R 3 , deuterium, F, alkyl, partially or fully deuterated alkyl, cycloalkyl, partially or fully deuterated cycloalkyl, aryl, partially or fully deuterated aryl, heteroaryl, partially or fully deuterated heteroaryl, nitrile, and combinations thereof.

40 . The compound of claim 38 , wherein at least one of R A or R B is —SiR 1 R 2 R 3 .

41 . The compound of claim 38 , wherein each of R 1 , R 2 , and R 3 is independently an aryl group or heteroaryl group.

42 . The compound of claim 38 , wherein at least one of R 1 , R 2 , and R 3 comprises a carbazole or aza-carbazole group.

43 . The compound of claim 38 , wherein X 1 and X 2 are each independently C and ring B is a 6-membered aromatic ring.

44 . The compound of claim 43 , two adjacent R B substituents of ring B are further joined to form a fused ring.

45 . The compound of claim 38 , wherein X 1 and X 2 are each independently C and ring B is a 5-membered heteroaryl ring; or wherein X 1 is N and X 2 is C.

46 . The compound of claim 38 , wherein X 3 -X 11 are each independently C; or wherein one of X 3 -X 11 is N.

47 . The compound of claim 38 , wherein R A for each occurrence is independently hydrogen, deuterium, alkyl, partially or fully deuterated alkyl, cycloalkyl, partially or fully deuterated cycloalkyl, aryl, partially or fully deuterated aryl, heteroaryl, partially or fully deuterated heteroaryl, or combinations thereof. ; and/or wherein R B for each occurrence is independently hydrogen, deuterium, alkyl, partially or fully deuterated alkyl, cycloalkyl, partially or fully deuterated cycloalkyl, aryl, partially or fully deuterated aryl, heteroaryl, partially or fully deuterated heteroaryl, or combinations thereof.

48 . The compound of claim 38 , wherein Y is selected from the group consisting of O and S.

49 . The compound of claim 38 , wherein the compound is selected from the group consisting of:

wherein:

R D independently represents zero, mono, or up to a maximum allowed substitution to its associated ring;

R D for each occurrence is independently a hydrogen or a substituent selected from the group consisting of —SiR 1 R 2 R 3 or —GeR 1 R 2 R 3 , deuterium, halogen, alkyl, partially or fully deuterated alkyl, cycloalkyl, partially or fully deuterated cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, partially or fully deuterated aryl, heteroaryl, partially or fully deuterated heteroaryl, nitrile, and combinations thereof;

Y A for each occurrence is independently selected from the group consisting of BR e , NR e , PR e , O, S, Se, C═O, S═O, SO 2 , CR e R f , SiR e R f , and GeR e R f ;

wherein R e and R f are optionally fused or joined to form a ring;

each of R e and R f 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 acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;

any two substituents are optionally joined or fused to form a ring; and

R A , R B , X 3 -X 11 , and Y are each as defined in claim 1 .

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

an anode;

a cathode; and

an organic layer disposed between the anode and the cathode,

wherein the organic layer comprises a compound of Formula I:

wherein:

ring B is a 5-membered heterocyclic ring, or a 6-membered carbocyclic ring;

each of X 1 and X 2 is independently C, CR, or N, with at least one of them being C;

each of X 3 -X 11 is independently C, CR, or N, with at least one of them being N, and two adjacent of X 3 -X 7 are carbon-fused to the shown moiety through the linkage indicated by the two squiggly lines;

Y is selected from the group consisting of O, S, Se, NR′, CR′R″, and SiR′R″;

each of R A and R B independently represents zero, mono, or up to a maximum allowed substitution to its associated ring;

each of R, R′, R″, R A , and R B is independently a hydrogen or a substituent selected from the group consisting of —SiR 1 R 2 R 3 or —GeR 1 R 2 R 3 , deuterium, halogen, alkyl, partially or fully deuterated alkyl, cycloalkyl, partially or fully deuterated cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, partially or fully deuterated aryl, heteroaryl, partially or fully deuterated heteroaryl, nitrile, and combinations thereof, with at least one of R A or R B comprising —SiR 1 R 2 R 3 or —GeR 1 R 2 R 3 ;

each of R 1 , R 2 , and R 3 is independently selected from the group consisting of alkyl, aryl group, heteroaryl group, and combinations thereof; and

any two substituents are optionally joined or fused to form a ring where chemically feasible.

51 . The OLED of claim 50 , wherein the organic layer is an emissive layer and the compound of Formula I is a host.

52 . The OLED of claim 51 , 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 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 e , NR e , PR e , O, S, Se, C═O, S═O, SO 2 , CR e R f , SiR e R f , and GeR e R f ;

R e and R f are optionally fused or joined to form a ring;

each of R a , R b , R c , and R d independently represents zero, mono, or up to a maximum allowed substitution to its associated ring;

each of R a , R b , R c , R d , R e and R f is independently hydrogen or a substituent selected from the group consisting of deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, borate, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and

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

53 . The OLED of claim 50 , wherein the organic layer is a blocking layer and the compound of Formula I is a blocking material in the organic layer.

54 . A consumer product comprising an organic light-emitting device (OLED) comprising:

an anode;

a cathode; and

an organic layer disposed between the anode and the cathode,

wherein the organic layer comprises a compound according of Formula I:

wherein:

ring B is a 5-membered heterocyclic ring, or a 6-membered carbocyclic ring;

each of X 1 and X 2 is independently C, CR, or N, with at least one of them being C;

each of X 3 -X 11 is independently C, CR, or N, with at least one of them being N, and two adjacent of X 3 -X 7 are carbon-fused to the shown moiety through the linkage indicated by the two squiggly lines;

Y is selected from the group consisting of O, S, Se, NR′, CR′R″, and SiR′R″;

each of R A and R B independently represents zero, mono, or up to a maximum allowed substitution to its associated ring;

each of R, R′, R″, R A , and R B is independently a hydrogen or a substituent selected from the group consisting of —SiR 1 R 2 R 3 or —GeR 1 R 2 R 3 , deuterium, halogen, alkyl, partially or fully deuterated alkyl, cycloalkyl, partially or fully deuterated cycloalkyl, heteroalkyl, heterocycloalkyl, aryl, partially or fully deuterated aryl, heteroaryl, partially or fully deuterated heteroaryl, nitrile, and combinations thereof, with at least one of R A or R B comprising —SiR 1 R 2 R 3 or —GeR 1 R 2 R 3 ;

each of R 1 , R 2 , and R 3 is independently selected from the group consisting of alkyl, aryl group, heteroaryl group, and combinations thereof; and

any two substituents are optionally joined or fused to form a ring where chemically feasible.

55 . The consumer product of claim 54 , 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.

56 . A formulation comprising a compound according to claim 38 .