Synthesis, single crystal structure and photo-luminescent property of bipolar compounds containing 1,3,4-oxadiazole and carbazolyl units

Two bipolar molecules 1a and 1b, which incorporate both electron-transporting oxadiazole and hole-transporting carbazolyl or N,N′-dimethylphenyl moieties within the conjugation system, were synthesized and characterized by 1H NMR, 13C NMR, elemental analysis and mass spectrometry. The molecular structure of compound 1a was further confirmed by single X-ray crystallography. The solutions of both compounds in CH2Cl2 individually displayed two absorption bands with λmax values at 376–378 nm and emitted with λmax values at 478–479 nm and quantum yields of 0.61–0.63. The cyclic voltammograms results showed that the carbazole-containing compound 1a has better hole injection ability than the N,N′-dimethylphenyl end-capped 1b.