Synthesis and characterization of periodic porous benzene-silica hybrid powders with cubic and hexagonal symmetries

摘要

Organosilica powders with uniformly distributed bridging benzene groups have been synthesized from the condensation of bis- or tris-(triethoxysilyl)benzene in the presence of cetyltrimethylammoniumbromide. The syntheses were performed under strong acidic conditions and the organic groups were always incorporated without cleavage of the Si-C bonds as indicated by solid state MAS NMR studies. Depending on the nature of the precursors, materials with different ordering were obtained : a 2D-hexagonal (p6m) phase was formed from the 1, 3-bis(triethoxysilyl)benzene, whereas the 1, 4-bis(triethoxysilyl)benzene lead to a cubic Pm3n phase. The surfactant was removed either by solvent extraction or by controlled calcination, which did not affect the mesostructure of the materials.