Despite extensive advancements in the design of artificial transporters for K+, Cl- and water, the development of Li+-selective systems has remained comparatively neglected, largely due to its smaller ionic radius and higher hydration energy that pose significant design challenges. To date, only three classes of artificial Li+ transporters have been reported. In this work, we introduce a novel fourth class of artificial Li+ channels, constructed from unique self-assembling organic imine cages that form membrane-spanning porous architectures. By incorporating bromine substituents, the resulting channel exhibits not only the highest Li+ transport activity (EC50 of 0.017 mol‰, relative to lipids) but also unprecedented selectivity, with Li+/Na+ and Li+/K+ selectivity factors of 44 and 52 respectively, marking a new benchmark in transmembrane Li+ transport performance.
Xu et al. (Tue,) studied this question.