Preparation of Chiral 1,4-Phenylene-silicas via Chiral Low-molecular-weight Amphiphiles

Chiral organic-inorganic hybrid silicas can be prepared via the self-assemblies of chiral surfactants and gelators as templates.However,the relationship between the chirality of the hybrid silica and the structure of the surfactant/gelator has not been systemically studied.Herein,a series of chiral low-molecular-weight amphiphiles（LMWAs） derived from L-valine was synthesized.Their alkyl chains were n-butadecyl,n-hexadecyl and n-octadecyl,respectively.They can form viscous liquids in pure water,and physical gels in tetrahydrofuran,cyclohexanone,acetonitrile,acetone,chlorobenzene and nitrobenzene.Chiral 1,4-phenylene-silicas were prepared via the self-assemblies of these LMWAs as templates.With increasing the alkyl chain length,the 1,4-phenylene-silicas changed from short mesoporous nanorods to long nanotubes.The circular dichroism spectra of the 1,4-phenylene-silicas indicated that the long nanotubes exhibit the strongest chirality.