"Bis-Clamp-Cavity Synergy", an Efficient Approach to Improve Guest Binding Properties of Macrocyclic Host and Its Application on Detection of Al and Arg in Living Cells.

Improving the selective and sensitive binding properties of macrocyclic hosts to target guests is always an interesting challenge. Herein, we introduce a novel "bis-clamp-cavity synergy" strategy to enhance the selectivity and binding sensitivity of pillararenes toward target guests. To achieve this goal, we designed and synthesized ,'-bis-hydroxynaphthoylhydrazone-functionalized conjugated pillar[5]arene (), in which bis-hydroxynaphthoylhydrazone plays the role of clamps, while the pillar[5]arene provides the macrocyclic cavity. The bis-clamps and macrocyclic cavity could supply synergistic binding for target guests through multicoordination interactions, multihydrogen bonds, C-H···π and cation···π interactions, and so on. Furthermore, the introduction of the conjugated pillar[5]arene can enhance the signal transmission ability, thereby improving the sensitivity for guest recognition. Benefiting from the bis-clamp-cavity synergy, exhibits efficient selective recognition for Arg and Al. It achieves colorimetric and fluorescent dual-channel recognition for Arg (with the LOD of 2.99 × 10 M) and ultrasensitive recognition of Al (with the LOD of 7.94 × 10 M). This strategy can be effectively applied to detect Arg and Al in aqueous solution and live cells.