Sensing rutile TiO2 through fluorescence of imidazole derivative

A new kind of imidazole derivative, 4,5-diphenyl-2(E)-styryl-1H-imidazole, has been synthesized. UV–vis absorption and fluorescence spectral studies show the interaction of the imidazole derivative with anatase and rutile phases of nanocrystalline TiO2. Anatase quenches the fluorescence emission of the imidazole derivative due to charge injection from the excited singlet state of imidazole derivative to the conduction band of anatase. On the other hand rutile enhances the fluorescence probably due to lowering of LUMO and HOMO levels of the imidazole derivative on ducking of the styryl moiety of the imidazole molecule into the void space of rutile TiO2, the HOMO and LUMO energies have been deduced from cyclic voltammetric results. The selective enhancement of fluorescence is useful to deduct and estimate nanocrystalline TiO2 rutile.