Solvent Structure around Lanthanoid(III) Ions in Liquid DMSO As Revealed by Polarizable Molecular Dynamics Simulations

Abstract

We present a study of the solvation of lanthanoid(III) ions in liquid dimethyl sulfoxide (DMSO) using molecular dynamics simulations employing a newly developed polarizable force field. The van der Waals (vdW) parameters were obtained for La(3+) and Lu(3+) (the first and the last in the lanthanoid(III) series) using ab initio data. The parameters of the other ions can be extrapolated based on physical considerations without additional (and costly) quantum chemistry calculations. This extrapolation procedure has been successfully applied to Gd(3+). The outcomes of our simulations turn out to be in agreement with both the experimental data available in the literature and the ab initio results. A small adjustment of the vdW parameters further increases the agreement with experiments and has allowed us to provide structures, geometrical parameters, and coordination numbers. For heavy lanthanoids (Gd and Lu) we obtain clearly an 8-fold coordination, with a distorted square antiprism (SAP) geometry in agreement with EXAFS and XANES experiments; for the La(3+) ion, our force field predicts a mixed situation with both the 8-fold SAP and 9-fold geometry where the SAP structure is capped by a ninth molecule added over one face.

Structure, Stability, and Electronic Properties of Dimethyl Sulfoxide and Dimethyl Formammide Clusters Containing Th4+

“…Furthermore, the collection of highly accurate geometrical and energetic theoretical data represents a necessary precondition to develop accurate, polarizable force fields to study such ions in the liquid state and to add dynamical information. 49 We should note that in the case of La 3+ , the information on structure and coordination numbers obtained from the cluster growing approach were very similar to what was then obtained in liquid phase and they turned out to be crucial in developing a general force field for molecular dynamics studies. The appropriateness of the cluster model approach is further assessed by the fact that in this kind of systems, as observed by Persson and co-workers, the crystal and liquid EXAFS signals are very similar; 34,47 this means that the main features of the metal−DMSO complexation are not modified by a change of bulk phase thus suggesting that the intrinsic ion−solvent interaction is strong enough to determine the solvation structure.…”

“…The great advantage of this approach is that it is possible to make use of accurate quantum chemistry methods and obtain not only the coordination geometries (that were found to be in agreement with the relevant experiments , ) but also information on the more likely coordination numbers. Furthermore, the collection of highly accurate geometrical and energetic theoretical data represents a necessary precondition to develop accurate, polarizable force fields to study such ions in the liquid state and to add dynamical information . We should note that in the case of La 3+ , the information on structure and coordination numbers obtained from the cluster growing approach were very similar to what was then obtained in liquid phase and they turned out to be crucial in developing a general force field for molecular dynamics studies.…”

“…In this work, we have used density functional theory (DFT) that was found to correctly address the properties of lanthanoids(III) in DMSO. 46,49 The outline of the paper is the following: we first describe the computational methods employed and the clusters studied, then we report results for structures followed by those for energetics. Then, we describe the electronic properties of the binding of some prototypical clusters for the two solvents.…”

“…This makes DMF potentially a good model for DMPU at a lower computational cost even of course if in DMF the steric hindrance on one side of the carbonyl group is smaller. In this work, we have used density functional theory (DFT) that was found to correctly address the properties of lanthanoids­(III) in DMSO. , …”

How Does CeIII Nitrate Dissolve in a Protic Ionic Liquid? A Combined Molecular Dynamics and EXAFS Study

“…The parameters of the polarizable Buckingham potential between the Ce III and O atoms were taken from the work of Martelli et al., while for the non‐polarizable potential we used as reference the La−O values reported in the same work and adjusted them by considering the difference in ionic radii between La III and Ce III , with the same interpolation procedure used to develop force fields for lanthanoids(III) in water and dimethylsulfoxide . The Ce III parameters are reported in Table .…”