A pillararene/imidazolium rotaxane: solvent- and thermo-driven molecular motions and supramolecular gel formation†
Based on the pillararene/imidazolium recognition motif, a rotaxane was effectively prepared. Solvent/temperature triggered molecular motions of the pillararene ring on the imidazolium axle were successfully realized. By comparison of proton NMR spectra of the rotaxane in different solvents, we found that if we increased the solvent polarity, the pillararene ring gradually moved away from the imidazolium part. In DMSO, we also could adjust the binding site of the pillararene ring by changing the temperature. Furthermore, in DMSO, the rotaxane self-assembled to form a supramolecular gel, which showed multiple stimuli-responsiveness.