Syntheses, structures, and luminescent properties of dipyridylamine-functionalized anthracene and its complexes.

A novel multidentate ligand with 2,2'-dipyridylamine functionalities, 1,8-bis[4-(2,2'-dipyridylamino)phenylacetylenyl]anthracene (1), has been synthesized through a double Sonogashira coupling reaction and characterized by NMR spectroscopic, elemental, and X-ray diffraction analyses. Compound 1 can bind to either one metal center as a tetradentate ligand or two metal centers as a double-bidentate ligand. In the double-bidentate mode, the distance between the two metal centers may vary significantly. Compound 1 displays bright blue luminescence in the solid state and in solution with a quantum efficiency of 64% relative to 9,10-diphenylanthracene. While the dirhodium complex of 1 shows no luminescence, the two zinc complexes of 1 display blue luminescence with quantum efficiencies slightly lower than that of 1. Organic light-emitting devices (OLEDs) using 1 as the emitter show a maximum current efficiency of 7 cd/A.