Related Experiment Video
Updated: Aug 11, 2026
Thermochemical Studies of Ni(II) and Zn(II) Ternary Complexes Using Ion Mobility-Mass Spectrometry
Published on: June 8, 2022
Temperature effects on the structural and dynamical properties of the Zn(II)-water complex in aqueous solution: a
M Qaiser Fatmi1, Thomas S Hofer, Bernhard R Randolf
1Theoretical Chemistry Division, Institute of General, Inorganic, and Theoretical Chemistry, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria.
Abstract:
An ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulation at double-zeta restricted Hartree-Fock (RHF) level was performed at an elevated temperature of 363 K (90 degrees C) to study the temperature effects on the structural and dynamical properties of a Zn(II)-water complex in aqueous solution. The first hydration shell, consisting of 6 water molecules at a mean Zn-O distance of 2.16 A, was found to remain stable also at 90 degrees C with respect to exchange processes. The flexible second shell contains, in average, approximately 27 water ligands. To fully characterize the hydration structure, several other parameters such as radial and angular distribution functions (RDF and ADF) and tilt- and theta-angle distributions were evaluated and compared to data obtained at 298 K (25 degrees C). Temperature effects on the dynamics of the Zn(II)-water complex were studied in terms of water reorientations, mean ligand residence times (MRTs), and number of ligand exchange processes. To get further insight into the solute dynamics, additional data, in particular, librational and vibrational motions of water ligands and Zn-O stretching frequencies, were calculated. The second shell is considerably influenced by the elevated temperature, as the ligands' mean residence time is shortened to 4 ps from the value of 10.5 observed at room temperature. The values of the QM/MM MD simulation were also compared to the results of a classical molecular dynamics (CMD) simulation with two- plus three-body potential performed at 90 degrees C, revealing that an accurate description of the second shell and the dynamics of the Zn(II) hydrate needs the inclusion of quantum mechanics in the description.
More Related Videos
08:54Vibrational Spectra of a N719-Chromophore/Titania Interface from Empirical-Potential Molecular-Dynamics Simulation, Solvated by a Room Temperature Ionic Liquid
Published on: January 25, 2020
10:28Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy
Published on: May 27, 2018
Related Concept Videos
02:42Aqueous Solutions and Heats of Hydration
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
01:23States of Water
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
01:15¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
01:27Atomic Spectroscopy: Effects of Temperature
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...