Methoxytrimethylsilane (A), dimethoxydimethysilane (B), and trimethoxymethylsilane (C) were used to silylate porous silica gel, which was very thoroughly dried with thionylchloride. Products were characterized with elemental analysis and by CP / MAS NMR (29Si and 13C). Under these conditions monofunctional silane A yields monodentate silane-to-surface links (trimethylsiloxysilanes) plus some esterification of silanol sites by methanol, resulting from the main reaction. Bifunctional silane B yields mono- and bidentate silane-to-surface links under the described reaction conditions. Trifunctional silane C also yields mono- and bidentate links. Cross-linked tridentate groups are formed only after exposure to air or reaction with water.
Vankan, J. M. J., Ponjee, J. J., Haan, de, J. W., & Ven, van de, L. J. M. (1988). On the nature of chemical binding of organic silanes to water-free silica surfaces: a high-resolution solid-state NMR spectroscopic study. Journal of Colloid and Interface Science, 126(2), 604-609. https://doi.org/10.1016/0021-9797(88)90160-9