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.