Dynamics of Water in the Solvation Shell of an Iodate Ion: A Born–Oppenheimer Molecular Dynamics Study

Abstract

The iodate ion has an anisotropic structure and charge distribution. It has a pyramidal shape with the iodine atom located at the peak of the pyramid. The water molecules interact differently with the positively charged iodine and the negatively charged oxygen atoms of this anion, giving rise to two distinct solvation shells. In the present study, we have performed ab initio Born−Oppenheimer molecular dynamics simulations to investigate the dynamics of water molecules in the iodine and oxygen solvation shells of the iodate ion and compared the behavior with those of the bulk. The dynamics of water is calculated for both the BLYP and the dispersion-corrected BLYP-D3 functionals at room temperature. The dynamics of water in the solvation shells at higher temperatures of 353 and 330 K has also been investigated for the BLYP and BLYP-D3 functionals, respectively. The hydrogen bond dynamics, vibrational spectral diffusion, orientational and translational diffusion, and residence dynamics of water molecules in the two solvation shells are looked at in the current study. The ion−water hydrogen bond dynamics is found to be somewhat faster than that for water−water hydrogen bonds in the bulk, which can be attributed to a ring-like electron distribution on the iodate oxygens. The dynamical trends are connected to the water structure making/breaking properties of the positively charged iodine and negatively charged oxygen sites of the anion. Furthermore, orientational jumps of the iodate ion and also those of surrounding water molecules which are hydrogen bonded to the oxygen atoms of the iodate ion are also investigated. It is found that the nature of these orientational jumps can be different from those reported earlier for planar polyoxyanions such as the nitrate ion.

The Role of Hydrogen Bonding in the Preferential Solvation of 5-Aminoquinoline in Binary Solvent Mixtures

“…The study of solvation dynamics has been an area of intense activity over the last few decades and has provided insight into solute–solvent interactions at the molecular level. This field has been enriched by rigorous theoretical calculations and simulations − on one hand and state-of-the-art spectroscopic experiments − on the other. Synergy between experiments and theory has provided deep insight into the process. , Time-dependent fluorescence Stokes shift (TDFSS) is the most popular experimental technique in this context, ,− which makes use of fluorescent probes like coumarin dyes that are significantly more dipolar in their excited state than in their ground state. , TDFSS has been used, for example, to study protein–surface interactions, biological water dynamics, and hydrogen bonding networks .…”

Molecular reaction and dynamic mechanism of iodate reduction to molecular iodine by nitrogen(iii) in aqueous solution

“…24,25 Several previous studies have investigated the iodate reduction reaction at the multiple interfaces of atmospheric aerosol clusters. 26,27 Khanniche et al studied the micro-hydration mechanism of HOIO 2 , indicating that HOIO 2 is the most stable form in the gas phase and forms monohydrated HOIO 2 and dihydrated HOIO 2 at temperatures lower than 310 K, where no hydrated HOIO 2 was formed at high temperature. 28 Sharma et al 27 used AIMD to study the dynamics of water-related reactions in the IO 3 − solvation shell, where water molecules interact differently with the positively charged iodine and negatively charged oxygen atoms of the anion, resulting in two distinct solvation shells.…”

“…26,27 Khanniche et al studied the micro-hydration mechanism of HOIO 2 , indicating that HOIO 2 is the most stable form in the gas phase and forms monohydrated HOIO 2 and dihydrated HOIO 2 at temperatures lower than 310 K, where no hydrated HOIO 2 was formed at high temperature. 28 Sharma et al 27 used AIMD to study the dynamics of water-related reactions in the IO 3 − solvation shell, where water molecules interact differently with the positively charged iodine and negatively charged oxygen atoms of the anion, resulting in two distinct solvation shells. Using AIMD, Kumar et al 29 proposed a mechanism of iodine oxides aerosol formation and the subsequent growth that exploits the non-covalent interaction between iodine oxides (I 2 O 5 and I 2 O 4 ) and iodic acid (HIO 3 and HIO 2 ).…”

Insights into the Stabilization of Fluoride Ions in Ionic Liquids: Pointers to Better Fluorinating Agents

“…However, molecular simulations are powerful, realistic and have often played critical roles in providing microscopic insights, − and it is this tool that we deploy here to study the poor solvate ionic liquid, [EMIM]­F. x EG ( x = 0.5, 1, and 1.5).…”