| Abstract
| - Different position fluoro-substituted ligands (2-difluorophenyl-4-methoxypyridine) and related iridium complexes were synthesized. Photophysical and electrochemical properties of these iridium complexes have been investigated. To the best of our knowledge, bis[2-(2‘,4‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a2) exhibits the bluest emission at 452 nm in photoluminescence and electroluminescence spectra.
- A series of 2-difluorophenyl-4-methoxypyridine ligands were synthesized and successfully used toprepare iridium complexes including bis[2-(2‘,3‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III)[5-(2‘-pyridyl)tetrazolate] (5a1), bis[2-(2‘,4‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a2), bis[2-(2‘,5‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a3), bis[2-(3‘,4‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a4), and bis[2-(3‘,5‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a5). Interestingly, 5a4 exhibits 2‘-coordinated and 6‘-coordinated isomers. Thecoordination behavior of this ligand with iridium metal differed depending on the repulsion energy andthe delocalization energy effects of the iridium complexes. X-ray structural analysis technique wassuccessfully applied to interpret the different coordination behavior of 5a4. In addition, introducing themethoxy group to the well-known ligand (2-difluorophenylpyridine) successfully expanded the band gapof iridium complexes and made 5a2 exhibit the bluest emission at 452 nm. To the best of our knowledge,this is one of the bluest OLEDs based on a 2-difluorophenylpyridine-iridium coordination emitter.
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