Strongly diluted dimethyl-imidazolium chloride-alcohol solutions: solvents are structurally different but dynamic heterogeneities are similar.

Based on the analysis of dynamic properties of ionic liquid solutions, the descriptions of diffusion mechanisms are built for dimethylimidazolium chloride (dmim+/Cl-)-alcohol solute systems and the influence of the monohydric alcohols' molecular structure on their diffusion mechanisms in dmim+/Cl--alcohol at T = 400 K by molecular dynamics simulations are studied. From the analysis of radial distribution functions, MSDs, velocity autocorrelation function, and autocorrelation functions of dispersion we found that the motion of all components in IL dmim+/Cl--alcohol (ethanol, propanol) systems at T = 400 K occurs in the sub-diffuse regime and that the dynamics of the dmim+/Cl--alcohol (ethanol, propanol) systems is heterogeneous. The increase of the alkyl chain length of the alcohol molecule does not affect the motion of the ionic liquid components; instead, it increases the characteristic times describing the model representation of alcohol molecule diffusion at short and medium times, without affecting diffusion mechanisms.

Competition between Na⁺ and Rb⁺ in the minor groove of DNA.

The competition between Na⁺ and Rb⁺ ions in the minor groove of a synthetic B-DNA dodecamer d (CGCGAATTCGCG) is studied using molecular dynamics simulations as the ratio of these two ions changing from 9:1 to 1:9 with the DNA merged into the solvent of water molecule at 298 K. When the concentration of Rb⁺ ions increases, from minority to majority, Na⁺ ions are gradually released from the A tract, and the binding sites in the minor groove are occupied by Rb⁺ ions, extending from the A tract to the whole minor groove. Comparing Na⁺ with Rb⁺ ions, the conformation of the minor groove is influenced strongly by Na⁺ ions.