Covalent Organic Framework Interlayer Spacings as Perfectly Selective Artificial Proton Channels

Area of Science:

• Materials Science
• Chemical Engineering
• Biophysics

Background:

• Biological proton channels exhibit perfect selectivity, a challenging feat for artificial materials.
• This selectivity arises from confined spaces and hydrogen-bonded wires facilitating proton hopping.

Purpose of the Study:

• To develop artificial proton channels with perfect selectivity inspired by biological systems.
• To investigate the use of covalent organic frameworks (COFs) for selective proton transport.

Main Methods:

• Utilized interlayer spacings of hydrophilic functionalized COFs as artificial proton channels.
• Employed density functional theory (DFT) calculations to model proton transport mechanisms.
• Investigated the tunability of proton transport rates by adjusting functional group acidity.

Main Results:

• COF interlayer spacings demonstrated perfect selectivity, blocking all ions and molecules.
• Protons exhibited high diffusivity within the COF channels, comparable to bulk water.
• DFT calculations confirmed the formation of hydrogen-bonded wires enabling proton hopping.
• Proton transport rates were successfully tuned by modifying the acidity of the COF functional groups.

Conclusions:

• Covalent organic frameworks can serve as highly selective artificial proton channels.
• The design principle of mimicking biological proton channels is effective for artificial materials.
• Functional group acidity offers a viable strategy for controlling proton transport in COFs.