Toward single-site functional materials-preparation of amine-functionalized surfaces exhibiting site-isolated behavior

A well-defined amine-functionalized silica surface displaying evidence of isolated amine sites is prepared using a molecular patterning technique. A tritylimine patterning agent is used to spatially position the amine sites a minimum distance from each other, resulting in an organic loading of 0.345 mmol of NH2/g of solid. The amine-functionalized silica and its precursors were characterized by multiple techniques including thermogravimetric analysis, nitrogen physisorption, FT-Raman spectroscopy, and C-13 and Si-29 cross-polarization magicangle spinning (CPMAS) NMR spectroscopy. The reactivity of the amine surfaces are further characterized using probe reactions. All of the amine sites in the patterned material are observed to react uniformly, unlike amine-functionalized silicas prepared using traditional techniques. Furthermore, the patterned aminosilica showed evidence of site isolation, whereas a densely loaded amine-functionalized silica synthesized by traditional methods did not.