Supramolecular Porous Assemblies of Atomically Precise Catalytically Active Cerium-Based Clusters

Atomically precise metallic clusters offer total structural information lacking in metal oxide and nanoparticle catalysts. However, their use as heterogeneous catalysts requires accessible and robust catalytic sites, yet directing clusters into ordered and porous assemblies through functional control remains elusive. Herein, we report a supramolecular strategy to induce permanent porosity within assemblies of two cerium oxide clusters through the capping ligands used. Single-crystal X-ray crystallography and density functional theory calculations revealed cluster assemblies with accessible channels, while adsorption isotherms showed permanent porosity. The clusters exhibited a bulk modulus >5 GPa in variable pressure diffraction studies. X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, and Raman spectroscopy demonstrated mixed valency (Ce3+/Ce4+) and oxygen vacancies in the clusters. We benchmarked catalytic activities through the photooxidation of 2-propanol.