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arXiv · 1208.4752

Pairing of 1-hexyl-3-methylimidazolium and tetrafluoroborate ions in n-pentanol

P. Zhu·L. R. Pratt·K. D. Papadopoulos
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Abstract

Molecular dynamics simulations are obtained and analyzed to study pairing of 1-hexyl-3-methylimidazolium and tetrafluoroborate ions in n-pentanol, in particular by evaluating the potential-of-mean-force between counter ions. The present molecular model and simulation accurately predicts the dissociation constant Kd in comparison to experiment, and thus the behavior and magnitudes for the ion-pair pmf at molecular distances, even though the dielectric constant of the simulated solvent differs from the experimental value by about 30%. A naive dielectric model does not capture molecule structural effects such as multiple conformations and binding geometries of the Hmim+ and BF4- ion-pairs. Mobilities identify multiple time-scale effects in the autocorrelation of the random forces on the ions, and specifically a slow, exponential time-decay of those long-ranged forces associated here with dielectric friction effects.

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P. Zhu, L. R. Pratt, K. D. Papadopoulos. 2012-08-23. Pairing of 1-hexyl-3-methylimidazolium and tetrafluoroborate ions in n-pentanol. https://doi.org/10.1063/1.4764296

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