Porous hydrogen silsesquioxane monoliths

The synthesis of monolithic materials with built-in reactive sites opens up the opportunities for exploiting their reactivity for desired piuqroses with precision. In this context, hydrosilanes containing reactive Si—H bonds in monomeric and polymeric forms have been used for the reduction of organic compounds [60]. Therefore, as a solid material hydrogen silsesquioxane (H—SiOi s, HSQ) represents a reactive solid for which the reactivity can be used for desired purposes. However, the synthesis of monolithic HSQ directly from alkoxide precursor (tri-methoxy/ethoxysilane) is rather difficult, as the Si—H bond is very weak and can easily be cleaved imder basic and nucleophilic conditions, restricting the sol-gel only to the acid-catalyzed route, and only the synthesis of HSQ films and periodic mesoporous particles has been reported so far [61]. 

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Moitra, N., Kanamori, K., Shimada, T., Takeda, K., Ikuhara, Y.H., Gao, X., and Nakanishi, K. (2013) Synthesis of hierarchically porous hydrogen silsesquioxane monoliths and embedding of metal nanoparticles by on-site reduction. Adv. Funct. Mater., 23, 2714-2722. 

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