The Blue Phosphorescent Iridium Complexes Containing the Pyridyltriazole Derivatives as a Main Ligand

The titled iridium compounds involving the electron-withdrawing pyridyltriazole derivative as a main ligand were synthesized. The main ligand, 2-(5-methoxy-methyl)-2-H1,2,4-triazol-3-yl)pyridine (trzl-CH2OMe), was designed for development of the blue light-emitting iridium complexes. The ligand involves the electron-withdrawing moiety, N, which may contribute to lowering the HOMO energy level of the complex. In this paper, the new homoleptic complex, tris-(2-(5-(methoxymethyl)-2H-1,2,4-triazol-3-yl)pyridinato)iridium (Ir(trzl-CH2OMe)(3)), was synthesized with trzl-CH2OMe as the main ligand. The heteroleptic complexes containing trzl-CH2OMe and other ancillary ligands were also prepared, where the ancillary ligands, acac and pic, represent acetylacetonate and picolinate, respectively. The photophysical properties of the iridium complexes prepared herein, Ir(trzl-CH2OMe) (3), Ir(trzl-CH2OMe)(2)(acac), Ir(trzl-CH2OMe)(2)(pic) were investigated. Their photoluminescence maximum appeared at 445 nm, 460 nm and 472 nm, respectively. We also investigated the electrochemical properties of these iridium complexes for the possible application to organic light-emitting diodes.