摘要
A combination of molecular dynamics （MD） and density functional theory （DFT） calculations were used to study the hydration structures of K＋ and Na＋ ions under the confinement of 18-crown-6 in order to identify the role of water in the selectivity of 18-crown-6 towards K＋.The radial distribution functions,coordination num-bers,orientation structures and interaction energies were analyzed to investigate the hydration of K＋ and Na＋ in 18-crown-6/cation complexes.All calculations of K＋ and Na＋ in bulk water were also conducted for comparison.The simulation results show that the orientation distributions of the water molecules in the first coordination shell of K＋ are more sensitive to the confinement of 18-crown-6 than those of Na＋.It is more favorable to confine a K＋ in 18-crown-6 than a Na＋ in terms of interaction energy.Good agreement is obtained between MD results and DFT results.
分子的动力学(MD ) 和密度的联合功能的理论(DFT ) 计算被用来在 18-crown-6 的监禁下面学习 K+ 和 Na+ 离子的水和结构以便向 K+ 在 18-crown-6 的选择识别水的角色。光线的分发功能，协作数字，取向结构和相互作用精力被分析在 18-crown-6/cation 建筑群调查 K+ 和 Na+ 的水和。K+ 和 Na+ 的计算大批浇的所有也为比较被进行。模拟结果证明在 K+ 的第一协作壳的水分子的取向分布比 Na+ 的那些对 18-crown-6 的监禁更敏感。以相互作用精力比 Na+ 在 18-crown-6 限制 K+ 是更有利的。好同意在 MD 结果之间被获得， DFT 结果。
基金
Supported by the National Natural Science Foundation of China （20706029）
the National Basic Research Program of China （2009CB623407 2009CB219902）
Jiangsu Applied Chemistry and Materials Graduate Center for Innovation and Academic Communication foundation （2010ACMC03）
