Determining the conformation of surface species by DNPeEnhanced solid-state NMR
Résumé
We have recently shown how DNP could be used to selectively enhance the NMR signals from surfaces in a wide range of materials (DNP SENS). With the recent introduction of biradicals of high molecular weight like TEKPOL, enhancements of more than 100 are now routinely obtained at 9.4 T and 100 K for mesostructured materials. Such factors enable multi-dimensional correlation experiments and thus offer the prospect of obtaining unprecedented quantitative structural information on surface species. We will show that multi-nuclear correlation techniques can be applied to obtain quantitative measurements of distances in mesoporous silicas incorporating organometalic catalysts.