Theoretical Study of Hydration Effects on the Selectivity of 18-Crown-6 Between K⁺ and Na⁺

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• 作者：Xiaojing GUO^a ; Yudan ZHU^a ; Mingjie WEI^a ; Ximing WU^a ; Linghong LÜ ; ^a ; Xiaohua LU ; ^a ; ^{xhlu@njut.edu.cn"" rel=""nofollow}
• 关键词：18-crown-6 ; selectivity ; molecular dynamics ; density functional theory
• 刊名：Chinese Journal of Chemical Engineering
• 出版年：2011
• 出版时间：April 2011
• 年：2011
• 卷：19
• 期：2
• 页码：212-216
• 全文大小：276 K

文摘

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 numbers, 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.