Polypyridine‐Based Helical Amide Foldamer Channels: Rapid Transport of Water and Protons with High Ion Rejection

Synthetic strategies that enable rapid construction of covalent organic nanotubes with an angstrom‐scale tubular pore remain scarcely reported. Reported here is a remarkably simple and mild one‐pot polymerization protocol, employing POCl 3 as the polymerization agent. This protocol efficiently generates polypyridine amide foldamer‐based covalent organic nanotubes with a 2.8 nm length at a yield of 50 %. Trapping single‐file water chains in the 2.8 Å tubular cavity, rich in hydrogen‐bond donors and acceptors, these tubular polypyridine ensembles rapidly and selectively transport water at a rate of 1.6×10 9  H 2 O⋅S −1 ⋅channel −1 and protons at a speed as fast as gramicidin A, with a high rejection of ions.