MULTINUCLEAR NMR-SPECTROSCOPY STUDIES OF SILICA SURFACES

H-1 --> Si-29 cross polarization with magic-angle spinning is a valuable approach for observing local silicon environments on the silica surface. The H-1 combined rotation and multiple-pulse spectroscopy (CRAMPS) approach distinguishes clustered and isolated surface silanols. Correlations of the variations in Si-29 and H-1 peak intensities with silane loading level in silica gels derivatized with (CH3)(3)SiCl suggest an incorrect model of the silica surface that is inconsistent with models derived from more detailed considerations Other nuclides (e.g., H-2, C-13, and N-15, along with Si-29) provide valuable approaches for the characterization of local structure and motion in derivatized (silylated) silicas.