Arylene- and alkylene-bridged polysilsesquioxanes

Bis(triethoxysilyl)arylene monomers 1-5 and the 1,6-bis(trimethoxysilyl)hexylene monomer 6 were hydrolytically condensed under sol-gel conditions using both acid and base catalysts to produce their respective arylene- and alkylene-bridged polysilsesquioxane materials (X-1 through X-6). Polymerization reactions yielded gels within 24 h. One notable exception was the acid-catalyzed polymerization of 2,5-bis(triethoxysilyl)thiophene (X-5-S1) which required approximately 1 month to gel. The gels were processed by extracting with low dielectric solvents or by aqueous extraction. Solid state ¹³C and ²⁹Si CP MAS-NMR, infrared spectroscopy, and gas sorption porosimetry were measured on the xerogels. The materials were transparent, glass-like xerogels with surface areas as high as 1100 m²/g and porosity primarily confined to a micropore region (< 20 A ̊ diameters). Xerogels prepared using the aqueous extraction had surface areas between 500 and 956 m²/g.