Mesoporous Assembly of Aluminum Molecular Rings for Iodine Capture

Abstract

The effective capture and storage of radioiodine are of worldwide interest for sustainable nuclear energy. However, the direct observation of ambiguous binding sites that accommodate iodine is extremely rare. We presented herein a crystallographic visualization of the binding of iodine within mesoporous cages assembled from aluminum molecular rings. These nanocages are formed through π−π interactions between adjacent aluminum molecular rings. Compared with the general nanotubes arrangement, the supramolecular nanocage isomer exhibits better iodine adsorption behavior. The robust molecular nanocages demonstrate a high iodine vapor saturation uptake capacity of 50.3 wt % at 80 °C. Furthermore, the resulting adsorbent can be recycled. Singlecrystal X-ray diffraction reveals binding sites of molecular I 2 within the pores of the phenyl-based linkers stabilized by the strong I•••π interactions. These compounds represent an excellent model to deduce the trapping mechanism of guest molecules interacting with the host. In addition, this work develops a promising cluster-based aluminum material as iodine adsorbents.

An electrically conductive metallocycle: densely packed molecular hexagons with π-stacked radicals

“…2c ) plays a crucial role in overlapping the sides of hexagons and forming the ABCABC… sequence. Although the pyrazole group can form a variety of metallocycle-based polygons, 36 hexagons were selectively crystallized probably because of their compatibility with the helical stacking mode mentioned above.…”

“…In this work, pyrazole was selected as the terminal group of the organic linker because of their preferential construction of various bent coordination polymers 35 and metallocycles. 36 …”

Structural transformation of copper coordination complexes accompanied with chiral transformation

“…15 The types of ligands or metal ions and the reactivity and solubility of the linkers provide huge possibilities for the structures and properties of such complexes. [16][17][18][19][20][21] It is worth noting that small variations in the synthesis process can affect the final result, which is more obvious for multi-site and soft ligands, 22 and sometimes such differences can be large. In addition, many other factors, such as temperature, 8 solvents, 23,24 reaction pH, 25,26 additives, 27 surfactants, 28 auxiliary ligands, 29 guest molecules, 30 reaction sequence, 17 and light, 31 affect the self-assembly process, hence accurate prediction of the crystal structure is still a major challenge in crystal engineering.…”

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

“…To better understand and improve the adsorption performances, another quite important issue is to determine the accurate binding of the guests within the host frameworks [15] . Considering that, this study is particularly interested in the synthesis of the aluminum oxo clusters/aluminum oxo compounds (AlOCs) for iodine capture [16] . Therefore, here, it is expected that tailor‐made porous extended frameworks are designed by combining them with conjugated organic linkers, and besides, new insights into the fascinating binding interactions can be provided.…”