Published online by Cambridge University Press: 28 February 2011
The first representatives of a new family of microporous, aryl-bridged polysilsesquioxanes have been prepared by sol-gel processing of bis-1,4-(triethoxysilyl)benzene la, bis-4,4′- (triethoxysilyl)biphenyl 2a, bis-4,4′-(triethoxysilyl)terphenyl 3a, and bis-9,10-triethoxysilyl anthracene 4a. The bis(trichlorosilyl) analogs of la and 2a (lb and 2b, respectively) were also examined. The materials produced by hydrolysis and condensation of the monomers provide an opportunity to fully condense to a network with rigid-rod organic spacers interspaced at regular intervals in the silicate-like framework. The xerogels produced upon subsesquent processing of the gels have extremely high surface areas (256–1100 m2/g; BET) with porosities confined to the micropore domain (< 200 nm). Solid state (CP MAS) 13C and 29Si NMR were used to evaluate the extent of hydrolysis and degree of condensation in the xerogels. The porosity and thermal stability of the aryl bridged polysilsesquioxanes may lead to applications as chromatographic absorbents. The transparent materials may also have optical applications arising from both the gels′ high refractive indices and the covalent incorporation of ultraviolet chromophores.