Geometric isomers of asymmetric rigid four-membered chelating ring based deep-red-emitting iridium complexes featuring three charged (0, −1, −2) ligands

A new series of asymmetric four-membered chelating ring based geometric isomers of iridium complexes featuring three charged (0, −1, −2) ligands have been prepared. All isomers show effective deep-red emission and finally exhibit good OLED performance.