Université de Toulouse, INSA, UPS, LPCNO, Toulouse, France.
Phys Chem Chem Phys. 2011 Oct 6;13(37):16772-9. doi: 10.1039/c1cp22154j. Epub 2011 Aug 22.
The determination of the solvation shell of Hg(II)-containing molecules and especially the interaction between Hg(II) and water molecules is the first requirement to understand the transmembrane passage of Hg into the cell. We report a systematic DFT study by stepwise solvation of HgCl(2) including up to 24 water molecules. In order to include pH and salinity effects, the solvation patterns of HgClOH, Hg(OH)(2) and HgCl(3)(-) were also studied using 24 water molecules. In all cases the hydrogen bond network is crucial to allow orbital-driven interactions between Hg(II) and the water molecules. DFT Born-Oppenheimer molecular dynamics simulations starting from the stable HgCl(2)-(H(2)O)(24) structure revealed that an HgCl(2)-(H(2)O)(3) trigonal bipyramid effective solute appears and then the remaining 21 water molecules build a complete first solvation shell, in the form of a water-clathrate. In the HgCl(2), HgClOH, Hg(OH)(2)-(H(2)O)(24) optimized structures Hg also directly interacts with 3 water molecules from an orbital point of view (three Hg-O donor-acceptor type bonds). All the other interactions are through hydrogen bonding. The cluster-derived solvation energies of HgCl(2), HgClOH and Hg(OH)(2) are estimated to be -34.4, -40.1 and -47.2 kcal mol(-1), respectively.
确定含汞分子的溶剂化壳，特别是汞(II)与水分子之间的相互作用，是理解汞跨膜进入细胞的第一步。我们报告了一项系统的 DFT 研究，通过逐步溶剂化 HgCl2，包括多达 24 个水分子。为了包括 pH 和盐度的影响，还使用 24 个水分子研究了 HgClOH、Hg(OH)2 和 HgCl3-的溶剂化模式。在所有情况下，氢键网络对于允许 Hg(II)与水分子之间的轨道驱动相互作用至关重要。从稳定的 HgCl2-(H2O)24 结构开始的 DFT Born-Oppenheimer 分子动力学模拟表明，出现了一个 HgCl2-(H2O)3 三角双锥有效溶质，然后其余 21 个水分子以水笼合物的形式构建了完整的第一溶剂化壳。在 HgCl2、HgClOH、Hg(OH)2-(H2O)24 的优化结构中，Hg 也从轨道角度直接与 3 个水分子相互作用（三个 Hg-O 供体-受体型键）。所有其他相互作用都是通过氢键。HgCl2、HgClOH 和 Hg(OH)2 的簇衍生溶剂化能分别估计为-34.4、-40.1 和-47.2 kcal mol-1。
