The force field for imidazolium-based ionic liquids: Novel anions with polar residues

Abstract

Many molecules can be converted into ions via relatively simple procedures. These ions can be combined into ionic liquids (ILs). We develop a new force field (FF) for the seven selected AAILs comprising 1-ethyl-3-methylimidazolium cation and amino acid anions with polar residues. All anions were obtained via deprotonation of carboxyl group in analogy with acetate anion. We account for peculiar interactions between the anion and the cation by fitting electrostatic potential for an ion pair, in contrast to isolated ions. Furthermore, we account for hydrogen bonds obtained via electronic structure consideration. The developed model fosters computational investigation of ionic liquids.(1) Classical force field for amino acid ionic liquids was developed.(2) Electrostatic potential was derived using electronic structure description of a neutral ion pair.(3) The developed force field fosters numerical simulations of ionic liquids.

Virtual Site OPLS Force Field for Imidazolium-Based Ionic Liquids

“…However, given proper sampling, these effects can be minimized . For example, the velocity rescale thermostat has accurately reproduced transport properties in multiple ionic-liquid studies. − Alternative thermostats, including the Nosé–Hoover temperature coupling method, have been utilized in earlier ionic-liquid calculations . As Nosé–Hoover dynamics are nonergodic, a series of Nosé–Hoover chains are typically used to impart ergodicity on the thermostatted system .…”

Thermodynamic and Transport Properties Modeling of Deep Eutectic Solvents: A Review on gE-Models, Equations of State, and Molecular Dynamics

“…This refinement resulted in a noticeable improvement when predicting the diffusivities for [bmim]­[PF 6 ]. The use of reduced net charges has become popular in force field development and has been applied for a variety of ionic systems as it yields results that are in better agreement with experimental findings as ab initio MD simulations. ,,− The scaling of the ionic charges in nonpolarizable force fields may deliver a promising alternative to computationally demanding polarizable force fields, but it needs to be adjusted to experimental data or density functional theory (DFT) calculations. As more computational power has become available, polarizable force fields have grown in popularity during the past years.…”

Quantum chemistry calculation aided design of chiral ionic liquid‐based extraction system for amlodipine separation

“…The geometries of amlodipine enantiomers, anions and cations of AAILs were produced by optimization and modification based on the previously published configurations. [33][34][35][36] The optimization of ion pairs was done by placing the anions at different positions around the cations to construct different initial conformations and then optimizing them respectively. Conformation with the lowest energy was taken as global minimum for the AAIL.…”