Molecular dynamics simulation of aggregation in dimethyl sulfoxide–water binary mixture

On the composition dependence of thermodynamic, dynamic and dielectric properties of water-dimethyl sulfoxide model mixtures. NPT molecular dynamics simulation results

“…Presently, the most widely used models for DMSO are at the united atom level (DMSO-UA); each methyl group is considered as a single interaction site. Attempts to improve the description of the properties, either of pure DMSO or water-DMSO mixtures, by using flexible, all-atom, and polarizable DMSO models have been made in [28,51,52,53,54,55,56,57]. Note that the majority of MD studies A C C E P T E D M A N U S C R I P T…”

“…for the united atom models were done in the canonical, N V T , ensamble, using experimental densities for different compositions [35,36,37,41,45] or using microcanonical, N V E, simulations [28,40,42,43], rather than under N P T conditions [44,46,48,49,52]. In a comprehensive study of excess mixing properties of water -DMSO model mixtures (thirty two combinations of models) [39], N V T Monte Carlo simulations were used.…”

The local environment of the molecules in water–DMSO mixtures, as seen from computer simulations and Voronoi polyhedra analysis

“…Molecular dynamics simulations of water- DMSO mixtures, containing 10,20,30,40,50, 60, 70, 80, and 90 mol% DMSO, respectively, have been performed on the isothermalisobaric (N,p,T) ensemble at T = 298 K and at the pressure equal to the experimental vapor pressure at each mixture composition. In addition, simulations of the two neat systems have also been performed for reference.…”

“…In fact, there is a convergence in the literature that in the DMSO mole percentage range of 30-40 % the water-DMSO interactions due to hydrogen bonds are at maximum. 18 Indeed, DMSO:water complexes of the stoichiometry of 2:1 at high DMSO mole fraction, 24,26,30,32 as well as of 1:2, 6,8,24,[26][27][28] 2:3, 27 and 1:3 33 at low DMSO content were proposed in the literature, although the existence of the latter has also been questioned. 27 However, such complexes were rather scarcely observed directly, e.g., through a detailed multiparticle spatial distribution analysis, 27 instead, their existence was merely hypothesized in explaining anomalous dynamical and thermodynamic properties of the mixture and other experimental data, or concluded on the basis of indirect evidences, such as radial distribution functions.…”

CHAPTER 7. Excess Volumes of Liquid Nonelectrolyte Mixtures

“…Thus, DMSO can only act as proton acceptor when forming strong hydrogen bonds with water molecules, and clear evidence has been provided by numerous spectroscopic studies 544 and neutron scattering studies, 545,546 dielectric relaxation spectroscopy, 547 ultrasonic absorption and sound speed measurements, 548,549 and further corroborated by molecular dynamics simulations. [550][551][552][553][554] Depending on the composition, different dominant structures are observed. 551,555 In particular, in water-rich mixtures the tetrahedral structure associated with water molecules results in local structures predominantly characterised by a molecular ratio of DMSO : 2H 2 O.…”