Organic electroluminescent materials and devices

1 . A compound comprising a structure of Formula I:

wherein:

each X is independently C or N;

A 1 , A 2 , A 3 , and A 4 are each selected from the group consisting of BAr, O, S, Se, and NR,

each group Ar independently comprises one or more aromatic rings wherein one of said one or more aromatic rings of each group Ar directly bonds to B;

at least one of A 1 and A 2 is BAr, and one of A 3 and A 4 is BAr;

none of the Ar are joined with R A , R B , or R C to form a ring;

if two R C are joined for fused to form a ring, the two R C are joined to form a 5-membered ring which does not comprise any B atoms, or the two R C join to form a substituted or unsubstituted aryl or heteroaryl group, wherein said aryl or heteroaryl group formed by two R C is fused to Formula I;

where at least one of the following conditions are true:

1) A 1 and A 3 are both BAr;

2) A 2 and A 4 are both BAr;

3) At least one of X is N;

4) At least one of A 2 and A 3 is O or S, A 1 and A 4 are both BAr and Ar has the structure of Formula II:

wherein X 1 is C or N and ring A is a carbocyclic or heterocyclic ring,

wherein if X 1 is N, then said N is a ring atom of a 5-membered ring,

and wherein one of the following is true:

 i) at least one ring A is a heterocyclic ring;

 ii) two R C join to form a 5-membered ring which does not comprise any B atoms; or

 iii) two R C join to form a 6-membered heteroaromatic ring containing only carbon and nitrogen ring atoms and for at most one Ar, R D and R E join together to form a heteroaryl group;

R A , R B , R C , R D , and R E each independently represent zero, mono, di-substitution or the maximum allowable substitution;

each R, R A , R B , R C , R D , and R E is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, boryl, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;

any two of R A , R B , R C , R D , and R E can be joined or fused to form a ring.

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

3 . The compound of claim 1 , wherein each X is C.

4 . The compound of claim 1 , wherein at least one X is N.

5 . The compound of claim 1 , wherein A 1 , A 2 , A 3 , and A 4 are each independently selected from the group consisting of BAr and O, with the proviso that one of A 1 and A 2 is BAr, and one of A 3 and A 4 is BAr.

6 . The compound of claim 1 , wherein R A and R B are each independently selected from the group consisting of hydrogen, deuterium, alkyl, aryl, and heteroaryl.

7 . The compound of claim 1 , wherein condition (4) is true, and each R D is hydrogen or deuterium.

8 . The compound of claim 1 , wherein A 1 and A 3 are BAr, and A 2 and A 4 are O; or

wherein A 1 and A 4 are BAr, Ar has the structure of Formula II, and A 2 and A 3 are O.

9 . The compound of claim 1 , further wherein at least one of the following is true: (1) two R A substituents or two R B substituents are joined together to form a 6-membered aromatic ring; (2) two R C substituents are joined together to form a 6-membered aromatic ring; or (3) two R C substituents are joined together to form a 5-membered heterocyclic ring.

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

wherein A 5 and A 6 are each selected from the group consisting of BAr, O, S, Se, and NR.

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

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

wherein each Y A is independently selected from the group consisting of O, S, Se, and N—Ar 1 , each R 1 is selected from the group consisting of

and

each Ar 1 is independently selected from the group consisting of

each Ar is independently selected from the group consisting of

and

subject to the following provisos:

if the compound has the structure of:

then each Ar 1 is selected from the group consisting of:

and

if the compound has the structure of:

then one Ar 2 is selected from the group consisting of:

and

and the other Ar 2 is selected from the group consisting of:

13 . The compound of claim 1 , wherein condition (4) is true and X 1 is bonded at an ortho position relative to the bond of Formula II to Formula I.

14 . 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 the compound of Formula I according to claim 1 .

15 . The OLED of claim 14 , wherein the compound is an acceptor, and the OLED further comprises a sensitizer selected from the group consisting of a delayed fluorescence emitter, a phosphorescent emitter, and combination thereof.

16 . The OLED of claim 14 , wherein the compound is a fluorescent emitter, a delayed fluorescence emitter, or a component of an exciplex that is a fluorescent emitter or a delayed fluorescence emitter.

17 . The OLED of claim 14 , wherein the compound is a sensitizer, and the OLED further comprises an acceptor selected from the group consisting of a fluorescent emitter, a delayed fluorescence emitter, and combination thereof.

18 . The OLED of claim 14 , wherein the compound is a host, and the organic layer is an emissive layer that comprises a phosphorescent emitter.

19 . The OLED of claim 15 , wherein the sensitizer is a first phosphorescent emitter 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:

T is selected from the group consisting of B, Al, Ga, and In;

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 B R e , N R e , P R 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 can be fused or joined to form a ring;

each 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 a1 , R b1 , R c1 , R d1 , R a , R b , R c , R d , 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; and

any two adjacent substituents of R a , R b , R c , R d , R e and R f can be fused or joined to form a ring or form a multidentate ligand.

20 . 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 the compound of Formula I according to claim 1 .