Recently, Science Bulletin published the research findings of Professors Shi Weiqun and Mei Lei from the Institute of High Energy Physics, Chinese Academy of Sciences. The study presents a viable approach for engineering acyl-type metal nodes to create oxygen-rich interior sites within MOCs, enabling the specific recognition of metal ions, including radioactive contaminants, while preserving the structural integrity of the MOCs. A novel MOC, referred to as UOC, featuring a uranyl-sealed calix[4]resorcinarene (C[4]R)-based multisite cavity, was synthesized as a prototype. In UOC, peroxide-bridged dimeric uranyl units at both ends of the coordination cage provide abundant oxygen sites for coordination, forming a cryptand-like cavity that facilitates the efficient recognition and encapsulation of Sr 2+ through a size-matching effect. Additionally, hydrophobic binding cavities at both ends of UOC facilitate the co-encapsulation of two distinct guest species. Inspired by the strong binding affinity of UOC for Sr 2+ , it was employed as a solid adsorbent to capture low concentrations of Sr 2+ from strontium-contaminated simulated groundwater. A removal efficiency of 99.7% for Sr 2+ at an initial concentration as low as 0.013 mmol L -1 was achieved, demonstrating its significant potential for the selective removal of trace amounts of radioactive 90 Sr 2+ . In summary, this work demonstrates the feasibility of incorporating acyl-type metal nodes into MOCs for the recognition and encapsulation of metal ions, provides new insights into the design of precise recognition sites within MOC cavities, and proposes a novel strategy for developing materials to purify radioactive metals.
Science Bulletin