Ab initio QM/MM simulation of Ag+ in 18.6% aqueous ammonia solution: structure and dynamics investigations.

Structure and dynamics investigations of Ag(+) in 18.6% aqueous ammonia solution have been carried out by means of the ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulation method. The most important region, the first solvation shell, was treated by ab initio quantum mechanics at the Restricted Hartree-Fock (RHF) level using double-zeta plus polarization basis sets for ammonia and plus ECP for Ag(+).

The influence of heteroligands on the reactivity of Ni2+ in solution.

Quantum-mechanics based molecular dynamics simulations were used to investigate mono-, di-, tri- and tetraamino Ni2+ complexes in water. The simulations show an enormous influence of heteroligands on the reactivity of the first solvation shell of the Ni2+ ion. Comparing 17O-NMR measurements of identical systems with our simulation results shows a 10(4) times higher mobility of water molecules in the first solvation shell obtained from QM/MM MD simulations strongly affecting biochemically important properties of Ni2+ in the aqueous environment in living organisms.

Influence of electron correlation effects on the solvation of Cu2+.

Hybrid QM/MM MD simulations including electron correlation effects at MP2 level were performed to obtain an accurate picture of the solvation structure and the Jahn-Teller effect of the Cu2+ ion.

Gold(I) in liquid ammonia: ab initio QM/MM molecular dynamics simulation.

Structure and dynamics investigations of Au(I) ion in liquid ammonia have been performed by means of a molecular dynamics simulation based on ab initio quantum mechanical/molecular mechanical forces, where the first solvation shell was treated by quantum mechanics at Hartree-Fock level. The outer region of the system was described using a newly constructed classical three-body corrected potential. A rigid structure of the first solvation shell was observed with an average Au-N distance of 2.

Cu(II) in liquid ammonia: an approach by hybrid quantum-mechanical/molecular-mechanical molecular dynamics simulation.

To investigate the solvation structure of the Cu(II) ion in liquid ammonia, ab initio quantum-mechanical/molecular-mechanical (QM/MM) molecular dynamics (MD) simulations were carried out at Hartree Fock (HF) and hybrid density functional theory (B3 LYP) levels. A sixfold-coordinated species was found to be predominant in the HF case whereas five- and sixfold-coordinated complexes were obtained in a ratio 2:1 from the B3 LYP simulation. In contrast to hydrated Cu(II), which exhibits a typical Jahn-Teller distortion, the geometrical arrangement of ligand molecules in the case of ammonia can be described as a [2 + 4] ([2 + 3]) configuration with 4 (3) elongated copper-nitrogen bonds.

Structure and dynamics of Au+ ion in aqueous solution: ab initio QM/MM MD simulations.

Structure and dynamics of hydrated Au(+) have been investigated by means of molecular dynamics simulations based on ab initio quantum mechanical molecular mechanical forces at Hartree-Fock level for the treatment of the first hydration shell. The outer region of the system was described using a newly constructed classical three-body corrected potential. The structure was evaluated in terms of radial and angular distribution functions and coordination number distributions.

Characterization of dynamics and reactivities of solvated ions by ab initio simulations.

Based on a systematic investigation of trajectories of ab initio quantum mechanical/molecular mechanical simulations of numerous cations in water a standardized procedure for the evaluation of mean ligand residence times is proposed. For the characterization of reactivity and structure-breaking/structure-forming properties of the ions a measure is derived from the mean residence times calculated with different time limits. It is shown that ab initio simulations can provide much insight into ultrafast dynamics that are presently not easily accessible by experiment.

New insights into the Jahn-Teller effect through ab initio quantum-mechanical/molecular-mechanical molecular dynamics simulations of CuII in water.

The CuII hydration shell structure has been studied by means of classical molecular dynamics (MD) simulations including three-body corrections and hybrid quantum-mechanical/molecular-mechanical (QM/MM) molecular dynamics (MD) simulations at the Hartree-Fock level. The copper(II) ion is found to be six-fold coordinated and [Cu(H2O)6]2+ exhibits a distorted octahedral structure. The QM/MM MD approach reproduces correctly the experimentally observed Jahn-Teller effect but exhibits faster inversions (< 200 fs) and a more complex behaviour than expected from experimental data.

The influence of the Jahn-Teller effect and of heteroligands on the reactivity of Cu2+.

Experimentally hardly accessible Jahn-Teller inversions and the influence of heteroligands on the reactivity of Cu2+ are characterized by ab initio QM/MM MD simulations of Cu2+ ion and its amino complexes in water.

Structure and dynamics of metal ions in solution: QM/MM molecular dynamics simulations of Mn(2+) and V(2+).

Structural and dynamical properties of the transition metal ions V(2+) and Mn(2+) in aqueous solution, resulting from combined quantum mechanical (QM)/molecular mechanical (MM) molecular dynamics (MD) simulations have been compared. The necessity of polarization functions on the ligand's oxygen for a satisfactory description of such ions in aqueous solution is shown using V(2+) as test case. Radial distribution functions, coordination number distributions, and several angle distributions were pursued for a detailed structural comparison of the first hydration shells.