The thermodynamics of ion solvation in non-aqueous solvents remains of great significance for understanding cellular transport and ion homeostasis for the design of novel ion-selective materials and applications in molecular pharmacology. Molecular simulations play pivotal roles in connecting experimental measurements to the microscopic structures of liquids. One of the most useful and versatile mimetic systems for understanding biological ion transport is N-methyl-acetamide (NMA). A plethora of theoretical studies for ion solvation in NMA have appeared recently, but further progress is limited by two factors. One is an apparent lack of experimental data on solubility and thermodynamics of solvation for a broad panel of 1 : 1 salts over an appropriate temperature and concentration range. The second concern is more substantial and has to do with the limitations hardwired in the additive (fixed charge) approximations used for most of the existing force-fields. In this submission, we report on the experimental evaluation of LiCl solvation in NMA over a broad range of concentrations and temperatures and compare the results with those of MD simulations with several additive and one polarizable force-field (Drude). By comparing our simulations and experimental results to density functional theory computations, we discuss the limiting factors in existing potential functions. To evaluate the possible implications of explicit and implicit polarizability treatments on ion permeation across biological channels, we performed potential of mean force (PMF) computations for Li(+) transport through a model narrow ion channel with additive and polarizable force-fields.

No abstract

Several errors were found in the Results and Discussion section. We recognize the presence of some errors in eq 3 on p 4129 of the original paper (J. Chem. Eng. Data 2017, 62 (12), 4128−4132). It was noticed that errors in eq 3 preclude correct calculation of the apparent molar volumes of calcium chloride. This error was due to our mistake.

The values of densities in N-methylacetamide solutions of calcium chloride have been measured at atmospheric pressure using an Anton Paar digital vibrating U-tube densimeter at temperatures ranging from 308.15 to 328.15 K, ΔT = 5 K and in the concentration range from 0 to 0.355 mol·kg–1. The kinematic viscosity for these mixtures has been measured at the same thermodynamic conditions using an Ubbelohde viscometer. Partial molar volumes of N-methylacetamide; partial molar volumes and apparent molar volumes of calcium chloride, and thermal expansion coefficients of solutions have been calculated using the experimental values. Dependences of these properties on the electrolyte concentrations have been discussed.