Tetradentate cyclometalated platinum complex comprising trisubstituted pyrazole, preparation and use thereof

A tetradentate cyclopalladated palladium complex comprising trisubstituted pyrazole, wherein a structure of the complex is as shown in (I):

• wherein,
• Ra and Rb each are alkyl, alkoxy, cycloalkyl, ether, heterocyclyl, hydroxy, aryl, heteroaryl, aryloxy, monoalkylamino or dialkylamino, monoarylamino or diarylamino, halogen, sulfydryl, cyano, independently, or combination thereof;
• Rx is alkyl, alkoxy, cycloalkyl, heterocyclyl, ether, monoalkylamino or dialkylamino, monoarylamino or diarylamino, halogen, or combination thereof;
• Rx is hydrogen, deuterium, alkyl, alkoxy, cycloalkyl, heterocyclyl, ether, monoalkylamino or dialkylamino, monoarylamino or diarylamino, halogen or combination thereof;
• and
• R1, R2 and R3 each are hydrogen, deuterium, alkyl, alkoxy, ether, cycloalkyl, heterocyclyl, hydroxy, aryl, heteroaryl, aryloxy, monoalkylamino or dialkylamino, monoarylamino or diarylamino, halogen, sulfydryl, haloalkyl, independently, or combination thereof.