Effect of Substituents on Luminescence of New Hydroxytetraphenylimidazole Derivatives

Resumo

The effect of OMe and NO₂ substituents in the phenol ring of hydroxytetraphenylimidazole (HTPI) derivatives on their luminescence in solutions and in the solid phase has been studied. The presence of the nitro group leads to multiple luminescence. In addition to the band of the photoproduct of intramolecular proton transfer, which is single for unsubstituted HTPI, nitrosubstituted imidazoles additionally have emission bands at shorter and longer wavelengths. The ratio between the bands depends on the solvent, concentration, and excitation wavelength. In solutions and polymer media, it is possible to switch luminescence by changing the excitation wavelength, and under certain conditions, white light emission is observed.