Indirect Interactions Between Proton Donors Separated by Several Hydrogen Bonds

TL;DR

This paper broadens the understanding of proton conduction by demonstrating that proton donors can influence each other over multiple hydrogen bonds, enhancing proton mobility in concentrated acid systems.

Contribution

It introduces an expanded definition of the packed-acid mechanism, showing indirect proton donor interactions through multiple hydrogen bonds using ab initio calculations.

Findings

Proton donors can interact over several hydrogen bonds.

Indirect interactions affect proton diffusivity.

Expanded mechanism applies to concentrated proton donor systems.

Abstract

We expand the definition of our recently proposed proton conduction mechanism, the packed-acid mechanism, which occurs under conditions of concentrated proton donors. The original definition stated that acid-acid interactions, which help overcome the barrier of the rate-determining step, occur only when a hydrogen bond is formed directly between proton donors. Here, it is shown that proton donors can interact with each other even when the donors are separated via several H-bonds. The effect of these interactions on proton diffusivity is confirmed by ab initio calculations.