Synthesis, Configurational Analysis, Molecular Recognition and Chirality Sensing of Methylene‐Bridged Naphthotubes

Abstract

AbstractMacrocyclic 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 108 M−1) 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.