Alkenyl-Functionalized Open-Cage Silsesquioxanes (RSiMe₂O)₃R′₇Si₇O₉: A Novel Class of Building Nanoblocks

Abstract

Trifunctional incompletely condensed polyhedral oligomeric silsesquioxanes (RSiMe₂O)₃R'₇Si₇O₉ (<b>IC-POSS</b>s) are considered as intriguing building nanoblocks dedicated to constructing highly advanced organic-inorganic molecules and polymers. Up to now, they have been mainly obtained <i>via</i> hydrosilylation of olefins, while the hydrosilylation of the C≡C bonds has not been studied at all, despite the enormous potential of this approach resulting from the possibility of introducing 3, 6, or even more functional groups into the <b>IC-POSS</b> structure. Therefore, in this work, we present a highly selective and efficient synthesis of the first example of tripodal alkenyl-functionalized <b>IC-POSS</b>s, obtained <i>via</i> platinum-catalyzed hydrosilylation of the terminal and internal alkynes, as well as symmetrically and nonsymmetrically 1,4-disubstituted buta-1,3-diynes with silsesquioxanes (HSiMe₂O)₃R'₇Si₇O₉ (R' = <i>i</i>-C₄H₉ (<b>1a</b>), (H₃C)₃CH₂C(H₃C)HCH₂C (<b>1b</b>)). The resulting products are synthetic intermediates that contain C═C bonds and functional groups (e.g., OSiMe₃, SiR₃, Br, F, B(O(C(CH₃)₂)₂ (Bpin)), thienyl), which make them suitable for application in the synthesis of novel, complex, hybrid materials with unique properties.