Organic electroluminescent materials and devices

1. A compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment is a ligand L A of Formula I;

wherein:

rings A, B, C, D, and E are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring;

Z 1 -Z 12 are each independently C or N;

R A , R B , R C , R D , and R E each independently represents zero, mono, or up to a maximum allowed substitutions to its associated ring;

if an R A , R B , R C , R D , or R E represents no substitution, then said R A , R B , R C , R D , or R E is hydrogen;

if R A , R B , R C , R D , or R E represents a substituent, then each R A , R B , R C , R D , and R E is independently a substituent selected from the group consisting of deuterium, halide, alkyl, cycloalkyl, fluorinated alkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;

two substituents can be joined or fused together to form a ring;

wherein the ligand L A is complexed to a metal M at Z 1 and Z 6 ;

wherein the metal M is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, Ag, and Cu;

wherein M can be coordinated to other ligands; and

wherein the ligand L A can be linked with other ligands to form a tridentate, tetradentate, pentadentate, or hexadentate ligand.

2. The compound of claim 1 , wherein the at least five rings comprises two 5-membered rings and three 6-membered rings.

3. The compound of claim 1 , wherein the at least five rings comprises five aromatic rings.

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

5. The compound of claim 1 , wherein M is Ir, Pt or Pd.

6. The compound of claim 1 , wherein the ligand L A is linked with other ligands to form a tetradentate ligand.

7. The compound of claim 1 , wherein

ring A, ring C, and ring E are 6-membered rings, and ring B and ring D are 5-membered rings;

ring A, ring C, and ring E are 5-membered rings, and ring B and ring D are 6-membered rings;

ring A and ring E are 5-membered rings, and ring B, ring C, and ring D are 6-membered rings;

ring A and ring E are 6-membered rings, and ring B, ring C, and ring D are 5-membered rings; or

ring A, ring B, ring D, and ring E are 5-membered rings, and ring C is a 6-membered ring.

8. The compound of claim 1 , wherein Z 1 -Z 12 are C.

9. The compound of claim 1 , wherein at least one of Z 1 -Z 12 is N.

10. A compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment is a ligand L A having a formula selected from the group consisting of:

wherein each X 1 -X 2 is independently selected from the group consisting of C and N; wherein no more than two N atoms are bonded to one another;

R A , R B , R C , R D , and R E each independently represents zero, mono, or up to a maximum allowed substitutions to its associated ring;

if an R A , R B , R C , R D , or R E represents no substitution, then said R A , R B , R C , R D , or R E is hydrogen;

if R A , R B , R C , R D , or R E represents a substituent, then each R A , R B , R C , R D , and R E is independently a substituent selected from the group consisting of deuterium, halide, alkyl, cycloalkyl, fluorinated alkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;

wherein each Y 1 -Y 5 is selected from the group consisting of O, S, Se, NR, CRR′, SiRR′, GeRR′, and BR; and wherein R and R′ are independently selected from the group consisting of hydrogen, deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, and combinations thereof;

two substituents can be joined or fused together to form a ring;

wherein the dashed lines represent coordination to a metal M;

wherein the metal M is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, Ag, and Cu;

wherein M can be coordinated to other ligands; and

wherein the ligand L A can be linked with other ligands to form a tridentate, tetradentate, pentadentate, or hexadentate ligand.

11. The compound of claim 10 , wherein the ligand L A is selected from the group consisting of the following compounds:

wherein each X 1 -X 6 is independently selected from the group consisting of C and N; wherein no more than two N atoms are bond to one another; wherein each Y 1 -Y 7 is selected from the group consisting of O, S, Se, NR, CRR′, SiRR′, GeRR′, and BR; and wherein R and R′ are each independently selected from the group consisting of hydrogen, deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, and combinations thereof.

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

13. The compound of claim 1 , wherein the compound emits light upon photoexcitation at room temperature; wherein the emitted light has an emission spectrum characterized by a peak emission wavelength λ max when measured at a concentration of 0.1 mM in a solution of 2-methyl tetrahydrofuran; and wherein the full width at half maximum of the emission at λ max that is equal to or less than 20 nm.

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 a compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment is a ligand L A of Formula I;

wherein:

rings A, B, C, D, and E are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring;

Z 1 -Z 12 are each independently C or N;

R A , R B , R C , R D , and R E each independently represents zero, mono, or up to a maximum allowed substitutions to its associated ring;

if an R A , R B , R C , R D , or R E represents no substitution, then said R A , R B , R C , R D , or R E is hydrogen;

if R A , R B , R C , R D , or R E represents a substituent, then each R A , R B , R C , R D , and R E is independently a substituent selected from the group consisting of deuterium, halide, alkyl, cycloalkyl, fluorinated alkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;

two substituents can be joined or fused together to form a ring;

wherein the ligand L A is complexed to a metal M at Z 1 and Z 6 ;

wherein the metal M is selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, Ag, and Cu;

wherein M can be coordinated to other ligands; and

wherein the ligand L A can be linked with other ligands to form a tridentate, tetradentate, pentadentate, or hexadentate ligand.

15. The OLED of claim 14 , wherein the organic layer further comprises a host, wherein host comprises at least one chemical group selected from the group consisting of metal complex, triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.

16. 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 to claim 1 .

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 the compound of claim 10 .