Photofunctional hybrid silica microspheres covalently functionalized with metalloporphyrins

The entrapment of metalloporphyrins (with Zn2+ and Yb3+) in silica microspheres is achieved by modification of protoporphyrin IX (Pp-IX) molecules with three different organosilane precursors via the sol–gel method. The obtained hybrid materials are characterized by electronic absorption spectra, Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), 29Si MAS NMR spectrum, scanning electron microscopy (SEM), nitrogen adsorption/desorption isotherms and thermogravimetric analysis (TGA), and their luminescence properties have also been determined. The results reveal that the obtained porphyrins networks are covalently bonded to the inorganic matrix through the bridging action of the functionalized silica microspheres. Furthermore, it has also been observed that porphyrins molecules located in different environments exhibit different photophysical properties in the visible and near-infrared regions.