Crown ether–cycloparaphenylene hybrid multimacrocycles: insights into supramolecular gas sensing and biological potential

The topologically intriguing multimacrocyclic architecture is endowed with distinct physical and chemical properties. The synthesis of hybrid macrocycles combining crown ethers and cycloparaphenylenes (CPPs) presents a promising strategy for developing multifunctional supramolecular systems. Herein, we first report the precise construction of a series of crown ether-CPP hybrid multimacrocycles with enhanced photophysical properties and diverse host-guest interactions. Notably, the trimacrocyclic hybrid adopts a molecular tweezer-like conformation, resulting in a significantly higher fullerene binding affinity compared to the bismacrocycle. The fullerene complex showed improved conductivity and sensitivity with a limit of detection (LOD) of 19 ppb for NO₂ with excellent cyclic stability and reliability. Additionally, the bismacrocycle exhibits significant cytotoxicity against cancer cell lines at low concentrations and enables fluorescence-based detection of inflammatory responses, highlighting its potential for biosensing applications. These findings underscore the versatility of crown ether-CPP hybrid macrocycles in supramolecular sensing and biochemistry, offering new avenues for the design of functional nanomaterials.