New hybrid silsesquioxane materials with sterically hindered carbosilane side groups

Unique silsesquioxane materials, bearing highly sterically hindered carbosilane substituents at SiO_3/2 centre, were derived from a novel precursor – (Me₃Si)₃CSiMe₂CH₂CH₂Si(OEt)₃ – in a hydrolytic condensation process under nucleophilic catalysis conditions. As proved by analytical results, crystalline or ladder-like (Me₃Si)₃CSiMe₂CH₂CH₂SiO_3/2]_n (PT_SiSS) were obtained, depending on the applied reaction conditions. Due to the intrinsic features of (Me₃Si)₃CSiMe₂–carbosilane substituent (the bulk and large amount of Si–C bonds), the obtained ladder-like silsesquioxanes show specific properties (good solubility, low dielectric constant κ).