Sol-gel synthesis and structural characterization of new mesoporous aluminophosphosilicate glasses and luminescent hybrid materials

Full text: A new family of aluminosilicophosphate glasses has been prepared via sol-gel synthesis using aluminum lactate as a precursor. Following calcination near 650°C these materials show mesoporosity, with surface areas near 600 m² /g. They can be utilized to incorporate cationic luminescent rare-earth complexes (guest species) via ion-exchange to yield useful optical materials. As the photophysical properties of such complexes will greatly depend upon the intermolecular distances and interactions involved, the structural characterization of the host species and the hybrid materials is of great importance. Advanced high-resolution dipolar NMR techniques present an element selective, inherently quantitative approach towards the structural description or such amorphous materials. In particular, the use of dipolar NMR methods, which relate directly to internuclear distances and distance distributions give important information about the connectivities in the host network, the nature of specific guest-host interactions, as well as the spatial distribution (homogeneous dispersion versus clustering) of the guest species. Applications of these concepts will be presented for the characterization alumina-silica, sodium aluminosilicate, and sodium aluminophosphosilicate host networks, and the structural organization of luminescent metal complexes in these networks.(author)