Quantitative Characterization of Organosilane Monolayers by Oxidative Dissociation of Monolayer Molecules

Self-assembled organosilane monolayers on silica surfaces find many applications; however, their structural characterization is challenging. We found that organic molecules in these monolayers can be dissociated from the surface by cleaving C-Si bonds under mild conditions of Fleming-Tamao oxidation. Once removed from the surface, the monolayer molecules could be isolated, purified, and analyzed in solution using conventional analytical techniques including NMR and GC-MS. This method enables efficient cleavage of different organic molecules attached to silica supports (e.g., in mixed monolayers) and is tolerant to a wide range of functional groups. Organic monolayers can be dissociated from a range of silica substrates, including silica nanoparticles, silica gel, flat glass slides, and related inorganic oxides, such as alumina or titania.