Yang Yuchong, Ronson Tanya K, Hou Dingyu, Luo Kai H, Nitschke Jonathan R
Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, U.K.
Department of Mechanical Engineering, University College London, London, WC1E 7JE, U.K.
Angew Chem Int Ed Engl. 2025 Jul;64(29):e202505137. doi: 10.1002/anie.202505137. Epub 2025 May 19.
Herein we utilize the binding of fluoride to boron atoms to functionalize the interior of a boron-containing trigonal prismatic capsule that incorporates two triangular and three rectangular ligands, enabling the tuning of its guest binding properties. The methyl groups of the triangular ligands guide the rectangular ligands to adopt a "landscape" orientation to avoid steric hindrance. This small structural change gives rise to an enlarged interior cavity volume for guest encapsulation, as compared with a previously-reported trigonal prismatic capsule, where the same rectangular ligand took a "portrait" orientation with a non-methylated triangular ligand of similar size. The methylated triangular ligand contains a boron core, which can bind fluoride ions that point inward. These bound fluorides serve as hydrogen bond acceptors, which increases the affinity of the capsule for hydrogen-bond-donating alcohols, which are bound in preference to ketones of similar sizes. Moreover, this boron-containing trigonal prism selectively binds perrhenate over perchlorate, while fluoride binding modulates the cavity charge, leading to perrhenate ejection. These and similar endo-functionalized capsules may thus be of use in the fields of molecular recognition and separation.
在此，我们利用氟化物与硼原子的结合来对一种含硼三角棱柱形胶囊的内部进行功能化，该胶囊包含两个三角形配体和三个矩形配体，从而能够调节其客体结合特性。三角形配体的甲基基团引导矩形配体采取“景观”取向以避免空间位阻。与先前报道的三角棱柱形胶囊相比，这种微小的结构变化导致用于客体包封的内部空腔体积增大，在先前的报道中，相同的矩形配体与大小相似的非甲基化三角形配体采取“纵向”取向。甲基化的三角形配体含有一个硼核，其可以结合向内指向的氟离子。这些结合的氟化物作为氢键受体，增加了胶囊对氢键供体醇的亲和力，醇优先于大小相似的酮被结合。此外，这种含硼三角棱柱对过铼酸盐的选择性高于高氯酸盐，而氟化物结合调节空腔电荷，导致过铼酸盐排出。因此，这些以及类似的内功能化胶囊可能在分子识别和分离领域有用。
