1.D.152. The Dihydrazide/Dialdehyde Anion Nanochannel (DDA-NC) Family
Anion transmembrane nanochannels constructed from dynamic covalent helices (DCHs) have been developed (Zhang et al. 2021). The dynamic covalent structures can be synthesized by one-pot dynamic covalent reactions and helically self-fold into nanotubes through intramolecular hydrogen bonding and pi-pi interactions. Such helical structures can vertically self-assemble into long nanofibers under pi-pi stacking, and their hollow nanocavities form ion permeation pathways across lipid membranes. Single-channel electrophysiological signals provided solid evidence of DCHs following a channel rather than a carrier mechanism. Owing to the pore-forming capacity of DCHs, nanochannels are able to accelerate the movement of anions across lipid membranes with high transport activity (EC50 =0.08 mol %). Moreover, DCH channels show dehydration energy dependent anion selectivity. Such DCHs can be considered to be general channel scaffolds with economical synthesis and special nanocavities (Zhang et al. 2021).