Synthesis of efficient blue and red light emitting phenanthroline derivatives containing both hole and electron transporting properties

Two phenanthroline derivatives containing a hole transporting triphenylamine and an electron transporting 1,3,4-oxadiazole unit have been prepared with high yield. UV–vis absorption and fluorescence measurement indicated they are high efficient light-emitting materials. The compounds are 6-(5-(4-N,N′-diphenylaminophenyl)-1,3,4-oxadiazol-2-yl) quinoxalino[2,3-f] phenanthroline (9, λmax = 635 nm, 40% quantum yield), and 1-ethyl-2-(4-(5-(4-N,N′-diphenylaminophenyl)-1,3,4-oxadiazol-2-yl)phenyl)imidazo[4,5-f]phenanthroline (14, λmax = 461 nm, 78% quantum yield). Preliminary study on electroluminescence for the two fluorescent dyes prepared from vacuum evaporation resulted in blue and red light emitting organic light emitting diodes (OLED).