The synthesis and optical properties of novel 1,3,4-oxadiazole derivatives containing an imidazole unit

A series of 1,3,4-oxadiazole derivatives containing an imidazole unit were synthesized and characterized using 1H NMR, 13C NMR, mass spectrometry (or high-resolution mass spectrometry) and elemental analysis. The crystal structure of 2,5-bis(4-(1-n-butyl-4,5-diphenylimidazol-2-yl)phenyl)-1,3,4-oxadiazole was determined as monoclinic, space group C2/c type, using single crystal X-ray crystallography. For nine samples, UV–visible absorption coefficient (ɛ), maximum wavelength (λmax), fluorescence excitation wavelength (λex), fluorescence emission wavelength (λem), fluorescence quantum yield (ΦF), fluorescence lifetime (T) were measured in dichloromethane and in the solid state. For these selected compounds, thermogravimetric analysis was also employed and structure:optical behaviour characteristics were discussed.