Designable Assembly of Aluminum Molecular Rings for Sequential Confinement of Iodine Molecules.

Although numerous adsorbent materials have been reported for radioactive iodine capture, demands for the development of new absorbents that are economically viable and featured with reliable synthetic protocols still exist. Herein, in this paper, a coordination-driven self-assembly strategy towards adsorbents for sequential confinement of iodine molecules is reported. It should be noticed that these adsorbents are versatile heterometallic frameworks constructed from aluminum molecular rings of varying size, flexible copper ions and conjugated carboxylate ligands. Additionally, these materials can quickly remove iodine from cyclohexane solutions with a high removal rate (98.8%) and considerable loading capacity (555.06 mg/g). Heterometallic frameworks provided distinct pore sizes and binding sites toward iodine molecules and realize crystallographic visualization concerning sequential confinement of iodine molecules. This work not only sets up a bridge between molecular rings and infinite porous networks but also reveals molecular details for the underlying host-guest binding interactions at crystallographic resolution.