Silsesquioxane-Terpyridine Nano Building Blocks for the Design of Three-Dimensional Polymeric Networks

Novel polyhedral oligomeric silsesquioxanes (POSS) decorated with eight terpyridine moieties were synthesized in a one-pot procedure via Heck coupling reaction with the aim of investigating the possible formation of three-dimensional extended supramolecular organizations. The monosubstituted analogue was also prepared and used as a model compound. Both POSS-based nanostructures were extensively characterized via ¹H, ¹³C, and ²⁹Si nuclear magnetic resonance (NMR), ultraviolet-visible spectroscopies and combustion chemical analysis. The assembly of these nanocaged bricks and two different metal ions (Zn²⁺ and Fe²⁺) was investigated via ¹H NMR as well as absorption and emission spectroscopy. Both mono- and octa-terpyridine-functionalized POSS (O-POSS) displayed interesting photophysical properties. Moreover, under selected conditions, the O-POSS forms stable gels at room temperature and can easily be shaped in the form of a film with potential applications in nanotechnology.