Constructing a robust gigantic drum-like hydrophobic [Co₂₄U₆] nanocage in a metal-organic framework for high-performance SO₂ removal in humid conditions

Constructing a gigantic hydrophobic metal-organic cage is not only scientifically important, but also synthetically challenging. Little is still known about the one the self-assembly and succedent host-guest recognition of transitional-metal-actinides cages. Herein, we report an unprecedented gigantic transitional-metal-uranyl [Co₂₄U₆] drum-like nanocage templated by a propyl-fused imidazolate dicarboxylate ligand. This nanocage-based MOF (namely Cage-U-Co-MOF) shows a high thermal and chemical stability in water and weak acidic/alkaline solution, as well as an impressively hydrophobic nature. More importantly, the breakthrough test on the Cage-U-Co-MOF bed disclosed this material as a highly effective and selective adsorbent for the removal of trace SO2 (ppm level) from SO₂/CO₂ or SO₂/CO₂/N₂ mixture under both drying and humid conditions, which suggests its superior application in industrial desulfurization. This work outlines a fundamental molecule-designing concept for preparing hydrophobic transitional-metal-actinides cages for advanced host-guest recognition.