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

Angew Chem Int Ed Engl. 2020 Aug 3;59(32):13328-13334. doi: 10.1002/anie.202003512. Epub 2020 May 28.

Abstract

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 POCl3 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 1.6×109 H2 O⋅S-1 ⋅channel-1 and protons at a speed as fast as gramicidin A, with a high rejection of ions.

Keywords: Foldamers; helical structures; hydrogen bonds; nanotubes; supramolecular chemistry.