School of Basic Sciences, Indian Institute of Technology, Bhubaneswar, India.
J Phys Chem B. 2011 Nov 17;115(45):13241-52. doi: 10.1021/jp206027e. Epub 2011 Oct 21.
The solvation structure and dynamics of ions in aqueous N-methylacetamide (NMA) solutions are calculated using classical molecular dynamics simulations. Our results are analyzed in terms of varying composition ranging from pure NMA to pure water. We also examined the effect of varying water content on the structure and dynamics of a neutral solute. Altogether we have simulated 38 different systems in the present work. It is found that water molecules have preference over NMA for the ions irrespective of their charge and size, whereas the neutral solute is preferably solvated by methyl groups of NMA. The calculated self-diffusion coefficient values show comparatively slower dynamics for ions than the neutral solute which can be attributed to the stronger solvation of ions in aqueous NMA mixtures. Various dynamical properties associated with translational and rotational motion of solvents are also calculated, and similar slower dynamics of solvents is observed which can be attributed to the enhanced stability of the hydrogen bonds and formation of interspecies complexes in the mixtures.
采用经典分子动力学模拟研究了离子在水合 N-甲基乙酰胺（NMA）溶液中的溶剂化结构和动力学。根据从纯 NMA 到纯水的不同组成，对我们的结果进行了分析。我们还研究了水含量变化对中性溶质结构和动力学的影响。在本工作中，总共模拟了 38 种不同的体系。结果发现，水分子优先与离子相互作用，而与离子的电荷和大小无关，而中性溶质则优先被 NMA 的甲基所溶剂化。计算出的自扩散系数值表明，与中性溶质相比，离子的动力学较慢，这可以归因于离子在水合 NMA 混合物中的更强溶剂化作用。还计算了与溶剂的平移和旋转运动相关的各种动力学性质，并且观察到类似的较慢的溶剂动力学，可以归因于氢键的增强稳定性和混合物中形成的种间络合物。
