Tetradentate platinum and palladium complex emitters containing phenyl-pyrazole and its analogues

A compound of Formula I, Formula A-2, or Formula A-3:

• wherein M is platinum or palladium,
• wherein L1 is selected from the following structures:
• wherein Y1 is O, N, or S;
• Y2 is N or C;
• Y3 is N or C, Y4 is N;
• and V1 is a carbene carbon;
• wherein L2 and L3 each represent phenylene;
• wherein L4 is substituted or unsubstituted pyridine;
• wherein each of F1 and F2 is independently present or absent, wherein at least one of F1 and F2 is present, and each of F1 and F2 present is a fluorescent luminophore,
• wherein each of A1, A2, and A is independently NR3 or O,
• wherein V2 is C;
• V3 is C;
• and V4 is N;
• wherein each of X is N,
• wherein Ra is present or absent, wherein Rb is present or absent, wherein Rc is present or absent, wherein Rd is present or absent, wherein Rx is present or absent, and if present each of Rx, Ra, Rb, Rc, and Rd independently represents mono-, di-, or tri-substitutions, and wherein each of Rx, Ra, Rb, Rc, and Rd is independently 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, and
• wherein each R3 is independently 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, monarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, aralkyl, ester, alkoxycarbonyl, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphoramide, silyl, polymeric;
• or any conjugate or combination thereof.