Silyl‐functionalized Silsesquioxanes: New Building Blocks for Larger Si‐O‐Assemblies, including the First Si‐Si‐Bonded Silsesquioxanes

Novel silyl‐functionalized silsesquioxane building blocks have been prepared by treatment of Cy 7 Si 7 O 9 (OH) 3 ( 1 , Cy = c ‐C 6 H 11 ) with hexachlorodisilane or hexachlorodisiloxane, respectively, in the presence of triethylamine. Reactions in a 1:1 molar ratio afforded the trichlorosilyl‐functionalized silsesquioxane derivatives Cy 7 Si 8 O 12 SiCl 3 ( 2 ) and Cy 7 Si 8 O 12 OSiCl 3 ( 3 ). Related bis(silsesquioxanes), (Cy 7 Si 8 O 12 ) 2 ( 4 ) and (Cy 7 Si 8 O 12 ) 2 O ( 5 ) are accessible in a similar manner by employing a 2:1 molar ratio of the reactands. Compound 1 also served as a starting material in the preparation of the partially closed silsesquioxane cages Cy 7 Si 7 O 11 (OH)SiMe 2 ( 6 ) and Cy 7 Si 7 O 11 (OH)Si(OEt) 2 ( 7 ), while the related condensation product Cy 7 Si 7 O 10 (OSiMe 3 ) ( 9 ) was made by AlCl 3 ‐catalyzed elimination of water from Cy 7 Si 7 O 9 (OH) 2 OSiMe 3 ( 8 ). The molecular structure of 9 was determined by X‐ray diffraction.