The hydration of the mercury(I)-dimer - A quantum mechanical charge field molecular dynamics study

The complex and labile hydration structure of the dimeric mercury ion Hg22+ has been studied by means of the novel quantum mechanical charge field molecular dynamics approach (QMCF MD). This system has been chosen as a challenging target to assess and evaluate the applicability of the QMCF approach, as standard MM and QM/MM protocols face obstacles in the formulation of accurate ion-solvent interaction potentials, while the application of the QMCF approach allows to renounce these potentials as the respective contributions are all included in the quantum mechanical framework. The results of the simulation show that the Hg(I) dimer forms a very labile hydration structure. In average 3.7 ligands are bound to each of the Hg atoms, and the water molecules are exchanged on the picosecond timescale