Organic electroluminescent materials and devices

1 . A compound having a structure of Formula I:

wherein:

each of R 1 to R 7 is independently a hydrogen or a substituent selected from the group consisting of phenyl, and a system consisting of two to ten phenyl groups connected to each other;

at least two of R 1 to R 7 are not hydrogen;

if R 1 and R 3 are not hydrogen, then at least one of the following is true: 1) R 1 and R 3 are different from each other; or 2) at least one of R 1 or R 3 is an unsubstituted phenyl;

if one of the at least two R 1 to R 7 that is not hydrogen is the system consisting of two to ten phenyl groups connected to each other, then the phenyl group directly bonded to the structure of Formula I having X bonds to exactly one phenyl group;

R 8 and R 9 are each independently selected from the group consisting of phenyl, and a system consisting of two to ten phenyl groups connected to each other;

X is selected from the group consisting of O, S, and Se; and

L is selected from the group consisting of direct bond and

wherein m is an integer from 1 to 5, and R A is a hydrogen or a substituent selected from the group consisting of aromatic and heteroaromatic rings; and

subject to the following provisos i) to iv):

i) if L is biphenyl, one phenyl of the biphenyl bonds to ring A and the other phenyl bonds to ring B;

ii) if X is O, then least one of R 1 , R 3 , or R 5 is H;

iii) if X is S, then at least one of R 1 or R 6 is H but if R 6 is H and R 1 is not H, then at least one of R 3 or R 5 is H; and

iv) the following structures are excluded

 and

wherein at least one of the following conditions 1) to 4) is true:

1) M is 1, ring A and ring B are meta to each other, and R 1 to R 9 comprise a total of at least 6 phenyl groups;

2) at least one of R 1 to R 4 is not hydrogen and at least one of R 5 to R 7 is not hydrogen;

3) R 8 is phenyl and R 9 is biphenyl; or

4) X is S.

2 . The compound of claim 1 , wherein m is 1, ring A and ring B are meta to each other, and R 1 to R 9 comprise a total of at least 6 phenyl groups.

3 . The compound of claim 1 , wherein at least one of R 1 to R 4 is not hydrogen and at least one of R 5 to R 7 is not hydrogen.

4 . The compound of claim 1 , wherein R 8 is phenyl and R 9 is phenyl.

5 . The compound of claim 1 , wherein R 8 is phenyl and R 9 is biphenyl.

6 . The compound of claim 1 , wherein X is O.

7 . The compound of claim 1 , wherein X is S.

8 . The compound of claim 1 , wherein R A is selected from the group consisting of hydrogen, phenyl, biphenyl, and terphenyl.

9 . The compound of claim 1 , wherein L has a structure selected from the group consisting of a direct bond.

10 . The compound of claim 1 , wherein at least one of R 1 to R 9 comprises at least 3 phenyl groups wherein a first phenyl group bonds to the moiety containing atom X or bonds to ring B and the other two phenyl groups are bonded to the first phenyl at a meta position to each other.

11 . The compound of claim 1 , wherein at least one of R 1 to R 9 includes at least three phenyl groups.

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

wherein Ar is an aromatic or heteroaromatic ring.

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

wherein Ar is an aromatic or heteroaromatic ring.

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

15 . The compound of claim 1 , wherein R 1 and R 3 are not hydrogen and R 1 and R 3 are different from each other.

16 . The compound of claim 1 , wherein R 1 and R 3 are not hydrogen and at least one of R 1 or R 3 is an unsubstituted phenyl.

17 . 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 having a structure of Formula I:

wherein:

each of R 1 to R 7 is independently a hydrogen or a substituent selected from the group consisting of phenyl, and a system consisting of two to ten phenyl groups connected to each other;

at least two of R 1 to R 7 are not hydrogen;

if R 1 and R 3 are not hydrogen, then at least one of the following is true: 1) R 1 and R 3 are different from each other; or 2) at least one of R 1 or R 3 is an unsubstituted phenyl;

if one of the at least two R 1 to R 7 that is not hydrogen is the system consisting of two to ten phenyl groups connected to each other, then the phenyl group directly bonded to the structure of Formula I having X bonds to exactly one phenyl group;

R 8 and R 9 are each independently selected from the group consisting of phenyl, and a system consisting of two to ten phenyl groups connected to each other;

X is selected from the group consisting of O, S, and Se; and

L is selected from the group consisting of direct bond and

wherein m is an integer from 1 to 5, and R A is a hydrogen or a substituent selected from the group consisting of aromatic and heteroaromatic rings; and

subject to the following provisos i) to iv):

i) if L is biphenyl, one phenyl of the biphenyl bonds to ring A and the other phenyl bonds to ring B;

ii) if X is O, then least one of R 1 , R 3 , or R 5 is H;

iii) if X is S, then at least one of R 1 or R 6 is H but if R 6 is H and R 1 is not H, then at least one of R 3 or R 5 is H; and

iv) the following structures are excluded

 and

wherein at least one of the following conditions 1) to 4) is true:

1) M is 1, ring A and ring B are meta to each other, and R 1 to R 9 comprise a total of at least 6 phenyl groups;

2) at least one of R 1 to R 4 is not hydrogen and at least one of R 5 to R 7 is not hydrogen;

3) R 8 is phenyl and R 9 is biphenyl; or

4) X is S.

18 . The OLED of claim 17 , wherein the organic layer further comprises an h-host selected from the group consisting of:

wherein:

each of R A′ , R B , R C , R D , R I , R J , R K , R L , R M , R N , R O , R P , R Q , R R , R S , R T , R U , R V , and R W represent mono to the maximum allowable substitution, or no substitution;

each of Ar 2 and Ar 4 is a linker independently selected from the group consisting of a direct bond, aryl, and heteroaryl;

each of X 1 and Y 1 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′ ; and

each Ar 3 , R 4′ , R 5′ , R 6′ , R 7′ , R 8′ , R e′ , R f′ , R A′ , R B , R C , R D , R I , R J , R K , R L , R M , R N , R O , R P , R Q , R R , R S , R T , R U , R V , and R W is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.

19 . The OLED of claim 17 , wherein the h-host is selected from the group consisting of:

20 . A formulation comprising a compound of Formula I

wherein:

each of R 1 to R 7 is independently a hydrogen or a substituent selected from the group consisting of phenyl, and a system consisting of two to ten phenyl groups connected to each other;

at least two of R 1 to R 7 are not hydrogen;

if R 1 and R 3 are not hydrogen, then at least one of the following is true: 1) R 1 and R 3 are different from each other; or 2) at least one of R 1 or R 3 is an unsubstituted phenyl;

if one of the at least two R 1 to R 7 that is not hydrogen is the system consisting of two to ten phenyl groups connected to each other, then the phenyl group directly bonded to the structure of Formula I having X bonds to exactly one phenyl group;

R 8 and R 9 are each independently selected from the group consisting of phenyl, and a system consisting of two to ten phenyl groups connected to each other;

X is selected from the group consisting of O, S, and Se; and

L is selected from the group consisting of direct bond and

wherein m is an integer from 1 to 5, and R A is a hydrogen or a substituent selected from the group consisting of aromatic and heteroaromatic rings; and

subject to the following provisos i) to iv):

i) if L is biphenyl, one phenyl of the biphenyl bonds to ring A and the other phenyl bonds to ring B;

ii) if X is O, then least one of R 1 , R 3 , or R 5 is H;

iii) if X is S, then at least one of R 1 or R 6 is H but if R 6 is H and R 1 is not H, then at least one of R 3 or R 5 is H; and

iv) the following structures are excluded

 and

wherein at least one of the following conditions 1) to 4) is true:

1) m is 1, ring A and ring B are meta to each other, and R 1 to R 9 comprise a total of at least 6 phenyl groups;

2) at least one of R 1 to R 4 is not hydrogen and at least one of R 5 to R 7 is not hydrogen;

3) R 8 is phenyl and R 9 is biphenyl; or

4) X is S; and

an h-host selected from the group consisting of:

wherein:

each of R A′ , R B , R C , R D , R I , R J , R K , R L , R M , R N , R O , R P , R Q , R R , R S , R T , R U , R V , and R W represent mono to the maximum allowable substitution, or no substitution;

each of Ar 2 and Ar 4 is a linker independently selected from the group consisting of a direct bond, aryl, and heteroaryl;

each of X 1 and Y 1 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′ ; and

each Ar 3 , R 4′ , R 5′ , R 6′ , R 7′ , R 8′ , R e′ , R f′ , R A′ , R B , R C , R D , R I , R J , R K , R L , R M , R N , R O , R P , R Q , R R , R S , R T , R U , R V , and R W is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, boryl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.