Competitive Solvation of (Bis)(trifluoromethanesulfonyl)imide Anion by Acetonitrile and Water

TL;DR

This paper introduces PM7-MD, a new simulation method combining semiempirical PM7 with molecular dynamics, to efficiently and accurately model competitive solvation phenomena, demonstrated on a specific anion in mixed solvents.

Contribution

The work presents an alternative simulation approach, PM7-MD, that captures non-additive solvation interactions without system-specific force field reparametrization.

Findings

PM7-MD effectively models competitive solvation.

The method demonstrates robustness across different solvent systems.

It offers a cost-effective alternative to traditional force field methods.

Abstract

Competitive solvation of an ion by two or more solvents is one of the key phenomena determining the identity of our world. Solvation in polar solvents frequently originates from non-additive non-covalent interactions. Pre-parametrized potentials poorly capture these interactions, unless the force field derivation is repeated for every new system. Development cost increases drastically as new chemical species are supplied. This work represents an alternative simulation approach, PM7-MD, by coupling the latest semiempirical parametrization, PM7, with equation-of-motion propagation scheme and temperature coupling. Using a competitive solvation of (bis)(trifluoromethanesulfonyl)imide anion in acetonitrile and water, the work demonstrates efficiency and robustness of PM7-MD.