Self-organization of crystal-like aromatic–silica hybrid materials

Abstract

Non-porous organic–silica hybrid solids with a very long-range ordered structure are synthesized by hydrolysis/condensation of bridged organosilanes (EtO)₃Si–R–Si(OEt)₃ (R = phenylene or biphenylylene) in basic or acidic solutions. The hybrid materials have a lamellar structure in which phenylene and biphenylylene groups are packed in a head-to-tail manner within silicate sheets. The X-ray diffraction patterns of the materials exhibit several clear peaks due to the lamellar structure. Nuclear magnetic resonance analysis of the materials reveals that the organosilane monomers are polymerized to form a covalently bonded organo-silica network structure. The resultant hybrid materials display a very fine particle morphology, with particles of less than 100 nm in diameter consisting of a dense and non-porous material.