Silsesquioxane chemistry: Part 5. New silyl-functionalized silsesquioxanes

Treatment of Cy7Si7O9(OH)3 (1) with Me2SiCl2 (molar ratio 2:3) in the presence of triethylamine affords the Me2Si-bridged bis(silsesquioxane) derivative Me2Si[Cy7Si7O10(O2SiMe2)]2 (5). The novel silsesquioxane vinyl monomer Cy7Si7O9(OSiMe2CHCH2)3 (7) has been synthesized by reacting in situ generated Cy7Si7O9(OLi)3 (6) with three equivalents of Me2SiCl(CHCH2). The molecular structures of 5 and 7 as well as that of the known silyl-functionalized silsesquioxane precursor Cy7Si7O9(OH)(OSiMe3)2 (3) have been determined by X-ray diffraction.