Internal structure investigation of pyrogenic modified silica by fluorescent labeling

We present our recent investigation on the internal structure of hybrid materials based on pyrogenic chlorobenzylated silica obtained by classical heating and sonochemistry. A fluorescent labelling by the alkoxypyridylindolizine derivative was carried out by linking the chlorobenzyl pattern, of the native hybrid materials, by quaternization of the free pyridyl group contained in the fluorescent unit. The two fluorescent materials were characterized by InfraRed spectroscopy, Solid-state 13C NMR, Thermal analysis, SEM and the structural parameters were determined from the nitrogenʹs isotherm sorption using BET method and BJH model. It is shown that the fluorescence properties depend of the internal structure of materials and, consequently, of the synthesis methodology. So, the thermic way has furnished an open porous system while the sonochemical methodʹs has led to a more closed porous system.