Hydrated germanium (II): irregular structural and dynamical properties revealed by a quantum mechanical charge field...

Structural and dynamical properties of Ge (II) in aqueous solution have been investigated using the novel ab initio quantum mechanical charge field (QMCF) molecular dynamics (MD) formalism. The first and second hydration shells were treated by ab initio quantum mechanics at restricted Hartree-Fock (RHF) level using the cc-pVDZ-PP basis set for Ge (II) and Dunning double-zeta plus polarization basis sets for O and H. Besides ligand exchange processes and mean ligand residence times to observe dynamics, tilt- and theta-angle distributions along with an advanced structural parameter, namely radial and angular distribution functions (RAD) for different regions were also evaluated. The combined radial and angular distribution depicted through surface plot and contour map is presented to provide a detailed insight into the density distribution of water molecules around the Ge(2+) ion. A strongly distorted hydration structure with two trigonal pyramidal substructures within the first hydration shell is observed, which demonstrates the lone-pair influence and provides a new basis for the interpretation of the catalytic and pharmacological properties of germanium coordination compounds.