Organic electroluminescent materials and devices

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 comprising a ligand LA of Formula I
• wherein:
• ring A is selected from the group consisting of pyridine, pyrimidine, pyridazine, pyrazine, triazine, imidazole, triazole, pyrazole, and N-heterocyclic carbene;
• ring D is a 5-membered or 6-membered carbocyclic or heterocyclic ring;
• X1 to X7 are each independently C or N, X8 is C;
• ring D is attached to X8;
• no more than two of X1 to X7 in the same ring are N;
• the one of X1 to X4 attached to Z1 is C;
• Y is selected from the group consisting of O, S, Se, NR, BR, CRR′, SiRR′, and GeRR′;
• Z1 and Z2 are each independently C or N;
• RA, RB, and RC each represent zero, mono, up to the maximum number of allowed substitutions to its associated ring;
• RD represents mono, up to a maximum allowed substitution to its associated ring;
• R, R′, RA, RB, RC, and RD are each independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl, boryl, selenyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;
• and
• at least one RD is a carbocyclic or heterocyclic group, and
• any two substituents can be joined or fused together to form a ring, with the proviso that RC and RD do not join to form a ring,
• the ligand LA is coordinated to a metal M through the two dashed lines forming a 5-membered chelate ring;
• M can be coordinated to other ligands;
• and
• the ligand LA can be linked with other ligands to comprise a tridentate, tetradentate, pentadentate, or hexadentate ligand.

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 comprising a ligand LA of Formula I
• wherein:
• ring A is selected from the group consisting of pyridine, pyrimidine, pyridazine, pyrazine, triazine, imidazole, triazole, pyrazole, and N-heterocyclic carbene;
• ring D is a 5-membered or 6-membered carbocyclic or heterocyclic ring;
• X1 to X7 are each independently C or N, X8 is C;
• ring D is attached to X8;
• no more than two of X1 to X7 in the same ring are N;
• the one of X1 to X4 attached to Z1 is C;
• Y is selected from the group consisting of O, S, Se, NR, BR, CRR′, SiRR′, and GeRR′;
• Z1 and Z2 are each independently C or N;
• RA, RB, and RC each represent zero, mono, up to the maximum number of allowed substitutions to its associated ring;
• RD represents mono, up to a maximum allowed substitution to its associated ring;
• R, R′, RA, RB, RC, and RD are each independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, germyl, boryl, selenyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof;
• and
• at least one RD is a carbocyclic or heterocyclic group, and
• any two substituents can be joined or fused together to form a ring, with the proviso that RC and RD do not join to form a ring,
• the ligand LA is coordinated to a metal M through the two dashed lines forming a 5-membered chelate ring;
• M can be coordinated to other ligands;
• and
• the ligand LA can be linked with other ligands to comprise a tridentate, tetradentate, pentadentate, or hexadentate ligand.