Syntheses, structures, and electroluminescence of new blue luminescent star-shaped compounds based on 1,3,5-triazine and 1,3,5-trisubstituted benzene

Four novel blue luminescent star-shaped compounds 1,3,5-tris(di-2-pyridylamino) benzene, 1, 1,3,5-tris [p-(di-2-pyridylamino) phenyl] benzene, 2, 2,4,6-tris(di-2-pyridylamino)-1,3,5-triazine, 3, and 2,4,6-tris[p-(di-2-pyridylamino) phenyl]-1,3,5-triazine, 4, have been synthesized and fully characterized. Compounds 1, 2 and 4 were prepared from the reactions of appropriate s-triazine and 1,3,5-trisubstituted benzene compounds with di-2-pyridylamine via copper-mediated Ullmann condensation in good yield (45-85%). Compounds 1, 2 and 4 show glass formation. Compounds 1-4 emit a blue color both in solution and in the solid state. The emission maxima of compounds 1-4 in the solid state are at lambda = 412, 409, 393 and 440 nm, respectively. Fluorescence quantum yields of compounds 1-4 are 0.53, 0.16, 0.43 and 0.78, respectively. Electroluminescent devices using compounds 1-4 as the emitters were fabricated.