Metal assisted delayed fluorescent emitters for organic light-emitting diodes

A compound of General Formula I

• wherein:
• M represents Pt(II) or Pd(II);
• each of R1, R2, R3, R4, R5, and R6 is independently absent or present as a single substituent or multiple substituents, valency permitting, and each of R1, R3, R4, R5, R6 and R9 independently represents hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino;
• substituted or unsubstituted:
• aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric;
• or any conjugate or combination thereof;
• wherein two adjacent substituents R2 are present, the groups Y4a, Y4b, Y4c, or Y4d to which the groups R2 are bound are each C, and the two adjacent groups R2 are represented by Formula A:
• wherein * represents the bond to General Formula I;
• X represents O;
• X1 represents a single bond, O, S, Se, P═O, As═O, Bi═O, CR7R8, C═O, SiR7R8, GeR7R8, NR7, PR7, PR7R8, R7P═O, AsR7, R7As═O, S═O, SO2, Se═O, SeO2, BR7, BR7R8, AlR7, AlR7R8, R7Bi═O, or BiR7;
• each occurrence of R7 and R8 is independently absent or present as a single substituent or multiple substituents, valency permitting, and each of R7 and R8 independently represents hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino;
• substituted or unsubstituted:
• aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric;
• or any conjugate or combination thereof;
• or
• any two of R1, R2, R3, R4, R5, R6, R7, and R8 represent a covalent bond;
• any two of R1, R2, R3, R4, R5, R6, R7, R8, X, and X1 may together form a fused ring;
• A, B, C, and D each independently represents C, N, O, or S;
• Y1 and Y2 each independently represents hydrogen, deuterium, halogen, hydroxyl, thiol, nitro, cyano, nitrile, isonitrile, sulfinyl, mercapto, sulfo, carboxyl, hydrazino;
• substituted or unsubstituted:
• aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, alkyl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric;
• or any conjugate or combination thereof, wherein Y1 and Y2 may optionally together form a fused aromatic or heteroaromatic ring;
• Y3a, Y3b, Y4a, Y4b, Y4e, Y4d, Y4e, Y4f, Y4g, Y4h, each independently represents C or N;
• Z1 and Z2 each independently represents C or N;
• Z3 represents C;
• Z4 represents N;
• L4 represents benzene;
• L5 is present or absent, wherein, if present, L5 represents a benzene;
• L6 represents pyridine, imidazole, benzimidazole, or pyrazole,
• V1 and V2 are independently present or absent;
• wherein each of V1 and V2, if present, independently represents a covalent bond, CR7R8, or C═O;
• wherein when V1 is not present, then L4 is not bound to L5;
• and when V2 is not present, then L6 is not bound to L5;
• V3 is present or absent, wherein V3, if present, represents N or if valency permits, represents NR7;
• wherein when V3 is not present, then a Y2a is directly bound to Y2b;
• and
• each n is independently an integer, valency permitting.