title: Theoretical study of the solvation of HgCl2, HgClOH, Hg(OH)2 and HgCl3(-): a density functional theory cluster approach.
abstract: 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.
authors.affiliation: Université de Toulouse, INSA, UPS, LPCNO, Toulouse, France.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Castro
authors.forename: Aurélien
authors.initials: A
authors.lastname: Dommergue
authors.forename: Alexandre
authors.initials: A
authors.lastname: Renard
authors.forename: Christophe
authors.initials: C
authors.lastname: Ferrari
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ramirez-Solis
authors.forename: Laurent
authors.initials: L
authors.lastname: Maron
mesh_terms: D006863:Hydrogen-Ion Concentration; D008627:Mercuric Chloride / Q000737:chemistry*; D017669:Mercury Compounds / Q000737:chemistry*; D011789:Quantum Theory; D012996:Solutions; D013816:Thermodynamics
chemical_list: D017669:Mercury Compounds; D012996:Solutions; D008627:Mercuric Chloride