| Three new heteroleptic fluoro-phenylpyridinyl Ir(Ⅲ) complexes containing amide as the ancillary ligand (dfppy)2Ir(N-Phenylbenzamide)2, (dfppy)2Ir- (acetylaniline) 3, a ring-opening Ir complex with amid ligand—Ir (dfppy)2 (benzamide)(H2O) 4, and a new heteroleptic Ir(Ⅲ) complex fluoro-phenylpyridine (dfppy)2Ir(4fppy) 5 have been successfully synthesized. The 2-(2,4-difluorophenyl)- pyridine ligand was synthesized by Suzuki coupling reaction of 2-halopyridine with 2,4-difluorophenylboronic acid. Then, this ligand was mixed with IrCl3-3H2O in 2-ethoxyethanol at reflux temperature to obtain the chloro-bridged 2-(2,4-difluorophenyl)pyridinyl Ir(Ⅲ) dimer. Finally, amide, synthesized through the corresponding carboxylic acids and amines, was added into a solution of chloro-bridged 2-(2,4-difluorophenyl)pyridinyl Ir(Ⅲdimer and stirred in the presence of alkali to produce the desired four-membered ring Ir-amide complexes.The structures of these complexes were fully characterized by IR, NMR and element analysis, and furthermore the structeres of complex 2, 4 and 5 were determined by X-Ray diffraction analysis. In addition, the mechanisms for the formation of these complexes, especially for complexes 4 and 5, were discussed.The absorption and emission properties of these four complexes were systematically investigated. All the complexes give rise to similar absorptions at 240-480nm, and the maximum absorption of complex 2, 3, 4 and 5 is at 252, 254, 253 and 264 nm respectively. The maximum emission of complex 2, 3, 4, 5 is at 394, 478, 429 and 480 nm respectively, which indicates that complex 3 should be a better blue phosphorescent emitter for OLED.
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