Shape-Persistent Oxa- and Aza-calix[4]arene Hybrid Molecular Cage and Naked Eye Sensing of Fluoride

An oxa- and aza-calix[4]arene hybrid molecular cage with a large, shape-persistent cavity wrapped by aromatic rings was designed and synthesized via multifold efficient SNAr reactions. X-ray single-crystal analysis revealed that two THF molecules were encapsulated in the central cavity. Selective sensing of F- in apolar solvent leads to naked eye discriminable color change. Addition of CH3OH would recover the color of the molecular cage.

Automated summary

A novel molecular cage with a shape-persistent cavity wrapped by aromatic rings was successfully synthesized via efficient SNAr reactions. X-ray analysis confirmed the encapsulation of two THF molecules in the central cavity, enabling selective sensing of F- ions in apolar solvent with a visible color change. The addition of CH3OH could reverse the color back to its original state.