New Phosphorescent ppy-based Iridium Complexes Containing Electron-withdrawing Groups

For the development of blue-emitting Ir(III) complexes, a set of new ligands, 2-(3-Y-phenyl)-4-methoxypyridine where Y denotes an electron-withdrawing cyanyl (cpmpH) or acetyl group (apmpH), were designed and synthesized. The phosphorescent Ir complexes, IrL2(pic) (L = cpmp; 1, apmp; 2, pic = 2-picolinate) were synthesized via chloro-bridged dimers, [IrL2Cl]2 and characterized by NMR spectra and elemental anaylses. 1 and 2 show bluish-green light with the PL maxima of 476 and 481 nm, respectively and blue-shifted emission compared to green phosphorescent Ir(ppy)2(pic). The solution PL efficiency of 1 and 2 is 0.12 and 0.09, respectively.