Shenzhen Grubbs Institute, Guangdong Provincial Key Laboratory of Catalysis and Department of Chemistry, Southern University of Science and Technology, Xueyuan Blvd 1088, Shenzhen, 518055, China.
Angew Chem Int Ed Engl. 2022 Oct 17;61(42):e202211853. doi: 10.1002/anie.202211853. Epub 2022 Sep 12.
Macrocyclic hosts with a well-defined cavity are particularly appealing for supramolecular chemistry, but they are still rare. In this research, we reported a new class of macrocyclic hosts, namely methylene-bridged naphthotubes, with well-defined cavities. They were synthesized through TFA-catalyzed Friedel-Crafts reactions between alkoxy-substituted bisnaphthalenes and paraformaldehyde. A configurational selection was observed. Three-membered macrocycles possess a single cavity, while four-membered macrocycles adopt a double-cavity conformation or a self-filling conformation depending on the alkoxy length. The small homologue shows quite strong binding affinities (up to 10 M ) to organic cations, which is better than structurally similar but flexible macrocycles. This demonstrates the advantage of a well-defined cavity in molecular recognition. Moreover, these naphthotubes can be used as chirality sensors for chiral organic cations through different chirality transfer mechanisms.
大环主体具有明确的空腔，特别适合超分子化学，但它们仍然很少见。在这项研究中，我们报道了一类新的大环主体，即亚甲基桥联萘管，它们具有明确的空腔。它们是通过 TFA 催化的烷氧基取代的双萘与多聚甲醛之间的 Friedel-Crafts 反应合成的。观察到了构象选择性。三元大环具有单个空腔，而四元大环根据烷氧基长度采用双空腔构象或自填充构象。小分子同系物对有机阳离子具有相当强的结合亲和力（高达 10⁻⁶ M），优于结构相似但灵活的大环。这证明了分子识别中明确空腔的优势。此外，这些萘管可以用作手性有机阳离子的手性传感器，通过不同的手性转移机制。
