Solvatochromic Parameters and Preferential Solvation Behavior for Binary Mixtures of 1,3-Dialkylimidazolium Ionic Liquids with Water

Binary mixtures of 1,3-dialkylimidazolium based ionic liquids （ILs） and water were selected as solvent systems to investigate the solute-solvent and solvent-solvent interactions on the preferential solvation of solvatochromic indicators at 25 ℃. Empirical solvatochromic pa- rameters, dipolarity/polarizability （π^＊）, hydrogen-bond donor acidity （α）, hydrogen-bond acceptor basicity （β）, and Reichardt＇s polarity parameters （ET^N） were measured from the ultraviolet-visible spectral shifts of 4-nitroaniline, 4-nitroanisole, and Reichardt＇s dye. The solvent properties of the IL-water mixtures were found to be influenced by IL type and IL mole fraction （XIL）. All these studied systems showed the non-ideal behavior. The max- imum deviation to ideality for the solvatochromic parameters can be obtained in the XIL range from 0.i to 0.3. For most of the binary mixtures, the π^＊ values showed the synergistic effects instead of the ETN, α and β values. The observed synergy extent was dependent on the studied systems, such as the dye indicator and IL type. A preferential solvation model was utilized to gather information on the molecular interactions in the mixtures. The dye indicator was preferentially solvated on the following trend： IL〉IL-water complex〉water.

Preferential solvation of pomalidomide,an anticancer compound,in some binary mixed solvents at 298.15 K

Preferential solvation of pomalidomide(PMD)was explored in dimethyl sulfoxide(DMSO)-dimethylformamide(DMF),DMSO-tetrahydrofuran(THF),DMSO-methanol(Me OH),DMSO-isopropanol,DMSO-water,water-DMF,water-THF,water-Me OH,and water–isopropanol binary mixed solvents at 298.15 K.Bosch-Rose model was utilized to determine the electronic transition energies(ET)and other preferential solvation parameters,describing solute-solute and solute-solvent interactions.We found thatλmaxsituation shifted with dielectric constant of the pure solvents meaningfully.According to the obtained results,ETenhanced andλmaxshifted to the lower wavelengths as the percentage of DMSO decreased in the binary mixtures,remarking the important role of DMSO for stabilizing the excited state(π*)of PMD chromophore via efficient intermolecular solute-solvent interactions.In addition,the aqueous binary systems showed an optimum point for the ETvalues as the percentage of water changed in the solutions.The local mole fraction of the solvents in the cybotactic region was also estimated to describe the specific and non-specific interactions in the systems.