Artificial simple unimolecular channels based on acyclic cucurbituril and crown ether for selective transport of alkali metal cations

Compared with natural channel proteins, artificial transmembrane channels based on macrocyclic molecules offer several advantages, including low price, stable properties, ease of structure modification, and functionalization. These benefits are highly significant for research purposes. Following this approach, a series of unimolecular ion channels have been designed and synthesized using crown ether and acyclic cucurbituril. The structure of the artificial channels was confirmed by NMR and HR-MS spectra. These unimolecular transmembrane channels have demonstrated effective efficiency in inserting into the lipid bilayers and transporting alkali metal cations, which can be substantiated through comprehensive fluorescence experimentation. Additionally, the alkali metal cation transport efficiency of the artificial channels is tunable by varying the length of the linkers between crown ether and acyclic cucurbituril. Thus, this study not only presented a simple and feasible unimolecular channel that could transport sodium and potassium selectively but also provided a simple model for constructing complex and controllable artificial transmembrane channels. This work was supported by the National Natural Science Foundation of China 560 (NNSFC) (No. 21961017, and 21642001), and the Analysis and Testing Foundation of Kunming University of Science and Technology (grant numbers: 2021M20202118090), which are grateful 560 acknowledged.