Presented herein are the AlIII molecular ring architectures from 8‐ring to 16‐ring. Although there are numerous reported cyclic coordination compounds based on transition metals, gallium, or lanthanides, the Al versions are less developed due to the fast hydrolysis nature of Al3+ ion. With the assistant of monohydric alcohols, a series of atomic precisely Al molecular rings based on benzoates are synthesized. The ring expansion of these Al‐rings from 8‐ring to 16‐ring is related to the monohydric alcohol structure‐directing agents. Moreover, the organic ligands on the Al‐rings can be modified by using various benzoate derivatives, which lead to tunable surface properties of the Al‐rings from hydrophilicity to ultra‐hydrophobicity. Importantly, 4‐aminobenzoic acid bridged 16‐ring is soluble in organic solvents and exhibits high solution stability revealed by mass spectroscopy. Ligand substitution also can be performed between these Al‐rings, which reveal controllable ligand functionalization of these Al‐rings.

Although numerous adsorbent materials have been reported for the capture of radioactive iodine,t here is still demand for new absorbents that are economically viable and can be prepared by reliable synthetic protocols.H erein, we report ac oordination-driven self-assembly strategy towards adsorbents for the sequential confinement of iodine molecules. These adsorbents are versatile heterometallic frameworks constructed from aluminum molecular rings of varying size, flexible copper ions,a nd conjugated carboxylate ligands. Additionally,t hese materials can quickly remove iodine from cyclohexane solutions with ah igh removal rate (98.8 %) and considerable loading capacity (555.06 mg g À1 ). These heterometallic frameworks provided distinct pore sizes and binding sites for iodine molecules,a nd the sequential confinement of iodine molecules was supported by crystallographic data. This work not only sets up ab ridge between molecular rings and infinite porous networks but also reveals molecular details for the underlying host-guest binding interactions at crystallographic resolution.

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