Synthesis reactions, polyhedral oligomeric silsesquioxanes

The synthesis of polyhedral oligomeric silsesquioxane-siloxane copolymers has been achieved by Lichtenhan and coworkers. " " " Reaction of the hydroxyl groups on monomer 150 with iw-dimethylaminosilanes and siloxanes (151) resulted in the formation of polymers such as 152 using the methodology described in Scheme 36. " " This polymer had a glass transition at 23°C and a melting transition at 114°C. On the basis of GPC measurements, this polymer had a degree of polymerization of 21. 

A novel protocol has been reported by Chiacchio et al. (2007) for the synthesis of polyhedral oligomeric silsesquioxane (POSS) macromers by 1,3-dipolar cycloaddition reactions of vinyl- and styiyl-POSS withN-methyl-C-ethoxycarbonylnitrone and ethoxycarbonyl nitrite oxide. These reactions are promoted by microwave irradiation. 

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