Octakis(3‐azidopropyl)octasilsesquioxane: A Versatile Nanobuilding Block for the Efficient Preparation of Highly Functionalized Cube‐Octameric Polyhedral Oligosilsesquioxane Frameworks Through Click Assembly

A one‐step synthesis of octakis(3‐azidopropyl)octasilsesquioxane from commercially available octakis(3‐aminopropyl)octasilsesquioxane has been developed through a highly efficient diazo‐transfer reaction under very mild conditions. Nonaflyl azide is shown to be a safer, cheaper, and more efficient reagent for this transformation than the better known and generally used diazo‐transfer reagent triflyl azide. Octakis(3‐azidopropyl)octasilsesquioxane is an excellent nanobuilding block that can be readily octafunctionalized with a range of terminal alkynes by copper(I)‐catalyzed 1,3‐dipolar azide–alkyne cycloaddition to provide new functional nanocages, maintaining a perfect 3D cubic symmetry. The mildness, simplicity, and efficiency of this approach have been demonstrated in the preparation of a glyco‐polyhedral oligosilsesquioxane (POSS) conjugate and a BODIPY–POSS cluster (BODIPY=boron dipyrromethene).