Silsesquioxane Chemistry, 5. Retention of the Cu4O4 core upon formation of the first copper(I) silsesquioxane from tetrameric copper(I)-t-butoxide

The first copper(I) silsesquioxane derivative, Cu4O4[Cy7Si7O9(OSiMe3)]2 (4) was prepared by reacting tetrameric copper(I)-t-butoxide, (CuOtBu)4 (3), with the monosilylated silsesquioxane precursor Cy7Si7O9(OH)2(OSiMe3) (2) in a 1:2 molar ratio. An X-ray diffraction study revealed the presence of a centrosymmetric dimer. A slightly puckered Cu4O4 ring forms the central part of a complex structure comprising nine eight-membered inorganic ring systems.