title: Study on a set of bis-cyclometalated Ir(III) complexes with a common ancillary ligand.
abstract: Bis-cyclometalated iridium(III) complexes [Ir(F2ppy)2ZN] (FZN), [Ir(F2CNppy)2ZN] (FCZN), [Ir(DMAF2ppy)2ZN] (FDZN) and [Ir(MeOF2ppy)2ZN] (MeOFZN) (F2ppy = 4',6'-difluoro-2-phenylpyridinate, F2CNppy = 5-cyano-4',6'-difluoro-2-phenylpyridinate, DMAF2ppy = 4',6'-difluoro-4-dimethylamino-2-phenylpyridinate, MeOF2ppy = 4',6'-difluoro-4-methyl-2-phenylpyridinate and ZN = 3,5-dimethylpyrazole-N-carboxamide) emitting in the sky blue region were synthesized. We studied the effect of the ancillary ligand ZN and the substituents on the cyclometalating ligands on the crystal structures, photophysical and electrochemical properties and the frontier orbitals. Density functional theory (DFT) calculation results indicate that in FCZN and FDZN the cyclometalating ligands show negligible participation in the HOMO, the ancillary ligand ZN being the main participant along with the Ir(III) d-orbitals. MeOFZN exhibits the maximum photoluminescence quantum efficiency and radiative emission rates along with the dominant low frequency metal-ligand vibrations and maximum reorganization energy in the excited state. All the substituted complexes show more polar characteristics than FZN, FCZN possessing the highest dipole moment among the complexes. The performances of the solution-synthesised organic light emitting devices (OLEDs) of FZN, FCZN and FDZN doped in a blend of mCP (m-bis(N-carbazolylbenzene)) and polystyrene are studied.
authors: Samsung Advanced Institute of Technology, P. O. Box 111, Suwon, 440-600, Korea.
authors: Younghun
authors: Y
authors: Byun
authors: Woo Sung
authors: WS
authors: Jeon
authors: Tae-Woo
authors: TW
authors: Lee
authors: Yi-Yeol
authors: YY
authors: Lyu
authors: Seok
authors: S
authors: Chang
authors: Ohyun
authors: O
authors: Kwon
authors: Eunsil
authors: E
authors: Han
authors: Heekyung
authors: H
authors: Kim
authors: Myeongsuk
authors: M
authors: Kim
authors: Ha-Jin
authors: HJ
authors: Lee
authors: Rupasree Ragini
authors: RR
authors: Das
mesh_terms: D018360:Crystallography, X-Ray; D004563:Electrochemistry; D004579:Electron Transport; D004583:Electrons; D007495:Iridium / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry; D011789:Quantum Theory; D013696:Temperature
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D011137:Polystyrenes; D011725:Pyridines; D007495:Iridium; C023666:pyridine