A 2,6-diamidopyridine-based macrocyclic aromatic amide receptor with cascade ion pair recognition†

Abstract

Ion-pair receptors constitute an important class of synthetic receptors within the realm of host–guest and supramolecular chemistry. Their unique ability to simultaneously recognize and accommodate both cations and anions has rendered them invaluable across various applications. In this study, we have synthesized a cascade macrocyclic ion-pair receptor, composed of three 2,6-amidopyridine building blocks bridged by aromatic spacers. Notably, the diamide binding sites of this receptor exhibit a high degree of selectivity for fluoride ions. Furthermore, despite lacking any dedicated cation-binding sites within its macrocyclic structure, this receptor is capable of selectively binding tetraethylammonium cations through a series of cascade electrostatic interactions facilitated by the bound flouride ions.