A blue phosphorescent iridium(III) complex (1) bearing fluorine-substituted bipyridine (dfpypy) has been synthesized and characterized to investigate the effect of the substitution and replacement of the phenyl ring in ppy (phenylpyridine) with pyridine on the solid state structure and its photoluminescence. The optical properties and electrochemical behaviors of 1 have also been systematically evaluated. The structure of 1 has also been determined by a single-crystal X-ray diffraction analysis. There are varied intermolecular interactions caused by the pyridine and fluorine substituents, such as C-H...N, C-H...F, and pi...pi interactions of either face-to-face type or edge-to-face C-H...pi and halogen...pi in crystal packing. In electrochemistry, the remarkably higher oxidation potential than that of FIrpic was observed. The emission lambda(max) of 1 at room temperature is at 438 nm with a higher PL quantum efficiency. Complex 1 exhibits intense blue emission with high color purity (CIE x = 0.14, y = 0.12), which has been attributed to metal-to-ligand charge-transfer triplet emission based on DFT calculations.

New silole compounds based on the 7-azaindolyl and 2,2′-dipyridylamino groups, 1,1dimethyl-2,5-bis(4-N-7-azaindolylphenyl)-3,4-diphenylsilole (1), 1,1-dimethyl-2,5-bis(4′-N-7azaindoylbiphenylyl)-3,4-diphenylsilole (2), 1,1-dimethyl-2,5-bis(p-2,2′-dipyridylaminophenyl)-3,4-diphenylsilole (3), and 1,1-dimethyl-2,5-bis(p-2,2′-dipyridylaminobiphenylyl)-3,4-diphenylsilole (4), have been synthesized and structurally characterized. These new silole compounds are capable of binding to metal ions as demonstrated by the zinc(II) complex 5 obtained from the reaction of 3 with Zn(O 2 CCF 3 ) 2 (H 2 O) 3 , where 3 functions as a bridging-chelating ligand to zinc(II) ions. The structure of siloles 1 and 3, and complex 5 were determined by single-crystal X-ray diffraction analyses. Compound 5 displays an extended 1D polymer structure in the solid state with alternating molecules of 3 and a dinuclear unit of Zn 2 (O 2 CCF 3 ) 4 (H 2 O). Compounds 1-4 are bright green emitters in solution and in the solid state with emission λ max at 506, 511, 519, and 516 nm, respectively. In contrast, the emission maximum of complex 5 is blue-shifted (λ max ) 488 nm), which is attributed to the disruption of the conjugation of the functionalized phenyl rings with the central silole ring by zinc(II) coordination, as revealed by X-ray diffraction analysis. Electroluminescent devices using compounds 1 and 3 as the emitting layer and the electron-transporting layer have been fabricated successfully.

Two blue phosphorescent Ir(iii) compounds with a main fluorine-free bipyridine ligand have been synthesized.

Blue phosphorescent Pt(II) complexes with 2,3′-bipyridine-based tetradentate C^N chelating ligands have been designed and synthesized. To investigate the effect of the substitution of an electron-donating/withdrawing unit on the solidstate structure and photo-and electroluminescence, either fluorine or methoxy substituents were incorporated into the Ccoordinating pyridine ring. The molecular structures of all the complexes were fully characterized by different spectroscopic methods, including X-ray diffraction analysis. There are no Pt(II)•••Pt(II) intermolecular interactions in crystal packing. Pt(II) complexes bearing fluorine substituents emit bright blue phosphorescence with λ max 460 nm, while methoxy-functionalized Pt(II) complexes display red-shifted and bluish green emissions with λ max 490 nm. The electron-withdrawing group at the Ccoordinating pyridine ring produced a deeper HOMO (highest occupied molecular orbital) level in comparison to its electrondonating counterpart. However, the substituents on the linker do not affect luminescence properties. All of the complexes possess high thermal stabilities (decomposition temperature >300 °C) and electrochemical stabilities. Blue phosphorescent organic light-emitting diodes (PHOLEDs) using four Pt(II) dopants have been successfully fabricated with an external quantum efficiency of 17.6% (maximum) and 17.3% (at 100 cd/m 2 ). Moreover, a fluorine-substituted Pt(II) complex with a doping level of 50 wt % in nonoptimized white organic light-emitting diodes (WOLEDs) exhibits an external quantum efficiency of 8.5% and pure white emission with Commission Internationale de L'Eclairage (1931) coordinates (x, y) of (0.32, 0.34).