| 主权项 |
1. A compound comprising a ligand LA of formula I: wherein ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring; wherein R is fused to ring B and has the formula II: wherein the wave lines indicate bonds to ring B; wherein R1and R3 each independently represent mono, di, tri, or tetra substitution, or no substitution; wherein R2 represents mono or di substitution, or no substitution; wherein X1, X2, X3, X4, X5, X6, X7, and X8 are each independently carbon or nitrogen; wherein at least one of X1, X2, X3, X4, X5, X6, X7, and X8 is nitrogen; wherein Y1 is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO2, CR′R″, SiR′R″, and GeR′R″; wherein R1, R2, R3, R′, and R″ are each independently selected from the group consisting of hydrogen, deuterium, halogen, 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, or wherein any two adjacent substituents are optionally joined to form a ring, which can be further substituted; wherein LA is coordinated to a metal M; wherein LA is optionally linked with other ligands to comprise a tridentate, tetradentate, pentadentate, or hexadentate ligand; and wherein M is optionally coordinated to other ligands. |
