Hydration behavior of alkyl amines and their corresponding protonated forms. 1. Ammonia and methylamine.
Hydration behavior of alkyl amines and their corresponding protonated forms. 1. Ammonia and methylamine.
复制标题
烷基胺及其相应质子化形式的水合行为。
DOI：
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发表时间：
2007
影响因子：
2.9
通讯作者：
K. Gloe
中科院分区：
文献类型：
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作者：
Holger Hesske;K. Gloe
采用Car-Parrinello分子动力学模拟方法研究了氨/铵和甲胺/甲胺体系水化反应的结构和动力学。虽然甲胺与水性环境的相互作用很弱，但氨的相互作用比预期的要强得多。这两个质子化的物种显示出高度结构化的第一溶剂化领域。所有物种的溶剂交换机制也进行了研究，沿着与水合球的几何形状。将这些交换机制与已发表的铵离子交换机制进行比较，仅显示出微小的差异。各自的分布函数的分析，允许洞察这两个系统的溶剂化的热力学。计算的pKa值（9.23/10.65）与公布的实验值9.25和10.65非常接近。
The structure and dynamics of hydration of ammonia/ammonium and methylamine/methylammonium systems have been studied by Car-Parrinello molecular dynamics simulation. While methylamine interacts weakly with the aqueous environment, the interaction of ammonia is found to be much stronger than expected. Both protonated species show a highly structured first solvation sphere. The solvent exchange mechanisms for all species were also investigated, along with the geometry of the hydration spheres. Comparison of these exchange mechanisms with that published for the ammonium ion shows only a minor difference. Analysis of the respective distribution functions has allowed insight into the thermodynamics of solvation for both systems. The calculated pKa values (9.23/10.65) correspond very closely with the published experimental values of 9.25 and 10.65.