Preparation and fluorescent properties of the all-W and Mo/V-monosubstituted Keggin-tungstosilicate microtubes doped with fluorescein dye.

Abstract: Three new dye-doped inorganic-organic hybrid microtubes, SiMW11-F (M = W, Mo and V; F = fluorescein), have been obtained and characterized by X-ray diffraction, ultraviolet/visible spectroscopy, elemental analysis, thermogravimetric analysis. Comparative studies have been carried out on fluorescent properties of the three SiMW11-F microtubes and fluorescein. These fluorescent hybrid microtubes exhibit luminescent emission properties which are different from raw material fluorescein in the blue spectral region, which is suggests that different luminescence centers may be formed in the hybrid microtubes. The SiW12-F and SiMoW11-F microtubes show more similar fluorescent properties than the SiVW11-F microtubes, due to the differences in ionic radius and oxidation state between W/Mo and V. Furthermore, the three polyoxometalate components in the microtubes exhibit an inhibiting effect on photobleaching of fluorescence dye in the reaction system. [Copyright &y& Elsevier]