Template-assisted assembly of metal binding sites on a silica surface

Tridentate templates were synthesized to introduce three organized amino groups on the surface of silica gel. The template-assisted modification generates a monolayer of tris-aminopropyl sites that can be further modified to construct various metal binding sites. Bipyridyl and pyridyl aldehydes were reacted with the modified silica surface followed by NaBH4 reduction. Iron(II) and copper(II) complexes of these surface-bound ligands were characterized by UV and XPS spectroscopies. A library of metal binding ligands could be constructed by the reaction of the modified silica gel with a combination of different monodentate ligands.