Studies of solvation free energies of methylammoniums and irregular basicity ordering of methylamines in aqueous solution by a combined discrete-continuum model
Studies of solvation free energies of methylammoniums and irregular basicity ordering of methylamines in aqueous solution by a combined discrete-continuum model
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DOI：
10.1021/jp0377127
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发表时间：
2004-05-13
影响因子：
2.9
通讯作者：
Mo, YR
中科院分区：
文献类型：
--
作者：
Cao, ZJ;Lin, MH;Mo, YR
用一个组合的离散-连续统模型计算了MenNH4-n+ （n = 0,1,2和3）的溶剂化自由能，其中离子溶质和与氮原子结合的氢原子或质子周围第一层的溶剂分子用量子力学方法处理，剩余的溶剂用连续统模型模拟。结果表明，离散-连续统模型可以在化学精度范围内预测带电物质的溶剂化自由能。在计算出的溶剂化自由能的基础上，我们进一步探讨了一系列甲胺在水溶液中碱度不规则次序的本质。分析表明，短程溶质-溶剂相互作用在碱度反转中起着重要作用。
The solvation free energies of MenNH4-n+ (n = 0, 1, 2, and 3) have been computed by means of a combined discrete-continuum model, in which the ionic solute and the solvent molecules in the first layers around the hydrogen atoms or protons bonded to the nitrogen atom are treated quantum mechanically and the remaining solvent is simulated by a continuum model. The results show that the discrete-continuum model can predict the solvation free energies of charged species within the chemical accuracy. On the basis of the computed solvation free energies, we further explore the nature of the irregular order in basicity of a series of methylamines in aqueous solution. Analyses reveal that the short-range solute-solvent interactions play a very important role in the inversion of basicity.