Imprinting supramolecular chirality on silica from natural triterpenoid-regulated helical ribbons†
Supramolecular chirality has attracted significant attention because of its critical roles in the life and material sciences. In this study, a natural triterpenoid-tailored amphiphilic molecule C4-MOP was designed and synthesized, in which the pyridinium head group was modified on the skeleton of triterpenoid through an alkyl linker. The introduction of pyridinium not only offers a hydrophilic cation to promote the assembly process but also renders itself as the nucleation point to adsorb silica precursors. The results showed that by adjusting the solvent compositions and the concentration of C4-MOP, well-ordered helical nanoribbons with both right- and left-handedness were fabricated by the assembly of C4-MOP, where the hydrophilic pyridinium cations were helically displayed on the surface of ribbons. Subsequently, by taking advantage of electrostatic interactions between pyridinium and the silica precursor, the supramolecular chirality of C4-MOP was successfully imprinted onto the silica nanostructures using the gel–sol mineralization process. Our work provides a simple yet useful strategy to prepare chiral silica, which could promote the applications of chiral natural products in material science.