Metal-assisted delayed fluorescent emitters employing pyrido-pyrrolo-acridine and analogues

A complex of General Formula II:

• wherein:
• M is Pt (II) or Pd (II);
• V1a is N;
• V1b, V1c, and V1d are each independently C or N;
• V1e and V1f are each C;
• V2a, V2b, V2c, and V2f are each C;
• V2d and V2e are each independently C or N;
• V3a and V3d are each independently C or N;
• V3b, V3c, V3e, and V3f are each C;
• V4a, V4b and V4c are each independently C or N;
• V5a and V5e are each C;
• V5b, V5c, and V5d are each independently C or N;
• provided that:
• only one of V1b, V1c and V1d is N;
• only one of V2d and V2e is N;
• only one of V3a and V3d is N;
• only one of V4a, V4b and V4c is N;
• and
• only one or two of V5b, V5c, and V5d is N;
• X represents O or S;
• each of X1 and X2 are a single bond, CR7R8, SiR7R8, GeR7R8, PR7R8, BR7R8, or AlR7R8,
• wherein at least one of X1 and X2 represents CR7R8, SiR7R8, GeR7R8, PR7R8, BR7R8, or AlR7R8, and R7 and R8 join to form a ring represented by substituted or unsubstituted
• Y1 is CR, SiR, GeR, N, NR, P, P═O, As, As═O, B, BR, Al, AlR, Bi═O, or Bi;
• and
• each of R, R1, R2, R3, R4, R5, R7, and R8 is independently absent or present as a single substituent or multiple substituents, valency permitting, and each R, R1, R2, R3, R4, R6, R7, and R8 present independently represents 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;
• or any combination thereof.