Blue Phosphorescent Ir(III) Complex with High Color Purity: fac-Tris(2′,6′-difluoro-2,3′-bipyridinato-N,C<SUP>4 </SUP>′)iridium(III)

초록

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 center dot center dot center dot N, C-H center dot center dot center dot F, and pi center dot center dot center dot pi interactions of either face-to-face type or edge-to-face C-H center dot center dot center dot pi and halogen center dot center dot center dot pi in crystal packing. In electrochemistry, the remarkably higher oxidation potential than that of Flrpic 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.

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