An artificial sodium-selective subnanochannel

摘要

Single-ion selectivity with high precision has long been pursued for fundamental bioinspired engineering and applications such as in ion separation and energy conversion. However, it remains a challenge to develop arti-ficial ion channels to achieve single-ion selectivity comparable to their biological analogs, especially for high Na+/K+ selectivity. Here, we report an artificial sodium channel by subnanoconfinement of 4 '-aminobenzo-15-crown-5 ethers (15C5s) into similar to 6-angstrom-sized metal-organic framework subnanochannel (MOFSNC). The resulting 15C5-MOFSNC shows an unprecedented Na+/K+ selectivity of tens to 10(2) and Na+/Li+ selectivity of 103 under multicomponent permeation conditions, comparable to biological sodium channels. A co-ion-responsive single-file transport mechanism in 15C-MOFSNC is proposed for the preferential transport of Na+ over K+ due to the synergetic effects of size exclusion, charge selectivity, local hydrophobicity, and preferential binding with functional groups. This study provides an alternative strategy for developing potential single-ion selective chan-nels and membranes for many applications.

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