Host–Guest Interactions of Metal–Organic Cage-Capped Gold Nanoparticles

Abstract

Metal–organic cages (MOCs) are a class of porous materials made of metal ions and organic ligands. These self-assembled compounds have promising applications in catalysis, sensing, biomedicine, and energy storage due to their stability and tunability. Cages vary greatly in shape, internal cavity size, solubility, and net charge, enabling supramolecular binding to guest molecules with high affinity and selectivity. Our work focuses on tetrahedral MOCs constructed with zirconium-based nodes and phenyl-containing organic ligands. We modify gold nanoparticles (GNPs) with our cages to maximize selectivity and reactivity in hydrogenation reactions for industrial applications; cage porosity enables selectivity while maintaining high reactivity by providing access to the gold surface. In this study, we examined the effects of solvent and relative cage and guest size on host–guest behavior. Our objective was to identify a guest molecule with strong binding affinity for our cages. Through this, we could confirm the tetrahedral geometry of our MOCs. Further, we could use host–guest binding to block the cage internal cavity in hydrogenation control experiments. These experiments would prove that reactants must go through the pore during catalysis.https://digitalcommons.dartmouth.edu/wetterhahn_2025/1014/thumbnail.jp