Arylsilsesquioxane Gels and Related Materials. New Hybrids of Organic and Inorganic Networks

Molecular building blocks for the preparation of amorphous hybrid organic-inorganic network materials have been synthesized. Hydrolysis and condensation of bis(triethoxysilyl)aryl 1-4 and -ethynyl 5 monomers results in formation of aryland ethynyl-bridged polysilsequioxanes in the form of xerogels. The gels were glasslike materials composed of uniform aggregates of particles between 50 and 80 nm in diameter. Atomic force microscopy was used to examine the fine grained aggregate characteristics of phenyl-bridged polysilsesquioxanes. The aryl-bridged materials were microporous with surface areas as high as 1000 m²/g and thermally stable to 400 °C in air. Solid state ¹³C and ²⁹Si NMR spectroscopies were used evaluate the integrity of the aryl and ethynyl bridges and to determine the degrees of hydrolysis (semiquantitative) and condensation in the network materials.