Hydration numbers of biologically relevant divalent metal cations from ab initio molecular dynamics and continuum solvation methods.

0584482 - ÚOCHB 2025 RIV US eng J - Journal Article
Kalvoda, Tadeáš - Martinek, Tomáš - Jungwirth, Pavel - Rulíšek, Lubomír
Hydration numbers of biologically relevant divalent metal cations from ab initio molecular dynamics and continuum solvation methods.
Journal of Chemical Physics. Roč. 160, č. 8 (2024), č. článku 084308. ISSN 0021-9606. E-ISSN 1089-7690
R&D Projects: GA ČR(CZ) GA23-05940S
EU Projects: European Commission(XE) 101095957 - Q-SCALING
Research Infrastructure: e-INFRA CZ II - 90254
Institutional support: RVO:61388963
Keywords : absorption fine-structure * aqueous-solution * neutron-diffraction
Impact factor: 4.4, year: 2022
Method of publishing: Limited access
https://doi.org/10.1063/5.0192024

Hydration and, in particular, the coordination number of a metal ion is of paramount importance as it defines many of its (bio)physicochemical properties. It is not only essential for understanding its behavior in aqueous solutions but also determines the metal ion reference state and its binding energy to (bio)molecules. In this paper, for divalent metal cations Ca2+, Cd2+, Cu2+, Fe2+, Hg2+, Mg2+, Ni2+, Pb2+, and Zn2+, we compare two approaches for predicting hydration numbers: (1) a mixed explicit/continuum DFT-D3//COSMO-RS solvation model and (2) density functional theory based abinitio molecular dynamics. The former approach is employed to calculate the Gibbs free energy change for the sequential hydration reactions, starting from [M(H2O)2]2+ aqua complexes to [M(H2O)9]2+, allowing explicit water molecules to bind in the first or second coordination sphere and determining the most stable [M(H2O)n]2+ structure. In the latter approach, the hydration number is obtained by integrating the ion-water radial distribution function. With a couple of exceptions, the metal ion hydration numbers predicted by the two approaches are in mutual agreement, as well as in agreement with the experimental data.
Permanent Link: https://hdl.handle.net/11104/0352388