Spatial distribution of organic functional groups supported on mesoporous silica nanoparticles: a study by conventional and DNP-enhanced 29 Si solid-state NMR

Si correlation measurements, which unambiguously showed that post-synthesis grafting leads to a more homogeneous dispersion of propyl and mercaptopropyl functionalities than co-condensation. During the anhydrous grafting process, the organosilane precursors do not self-condense and are unlikely to bond to the silica surface in close proximity (less than 4 Å) due to the limited availability of suitably arranged hydroxyl groups.