Solvatochromic Absorbance Probe Behavior and Preferential Solvation in Aqueous 1-Butyl-3-methylimidazolium Tetrafluoroborate

Abstract

The hypothesis that aqueous, rather than pure, ionic liquids provide substantially altered physicochemical properties and versatile/increased solute solvation is addressed. Solvatochromic absorbance probes are utilized to gather information on aqueous solutions of a completely water-miscible ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF 4 ). A simplistic solvation model suggests possible preferential solvation of a watersoluble betaine dye by bmimBF 4 . The lowest-energy electronic absorption band of this dye is further used to interpret dipolarity/polarizability and hydrogen-bond donating (HBD) acidity of aqueous bmimBF 4 . On the basis of the responses of two other probes, N,N-diethyl-4-nitroaniline and 4-nitroaniline, dipolarity/polarizability, HBD acidity, and hydrogen-bond accepting basicity are separately assessed.

Volumetric Properties of the Ionic Liquid, 1-Butyl-3-methylimidazolium Tetrafluoroborate, in Organic Solvents at T = 298.15K

“…It is one of the most commonly used ionic liquids for which some physicochemical properties with other organic solvents have been studied. Its volumetric properties, viscosity and speed of sound in water [10][11][12][13], vapor-liquid equilibria in binary and ternary mixtures [14], liquid-liquid equilibria [15][16][17], vapor pressures of binary [BMIm] [BF 4 ] + water mixture [18], activity coefficients at infinite dilution with some organic solvents [19,20], mutual solubilities of this ionic liquid in organic solvents [21,22], volumetric and viscosity study in organic solvents [23], excess thermodynamic functions of [BMIm] [BF 4 ]+H 2 O systems at 298.15 K [24], aggregation behavior in aqueous solutions [25], thermophysical properties in organic solvents [26,27], and dipolarity/polarizability and hydrogen-bond donating (HBD) acidity of aqueous [BMIm][BF 4 ] [28] have been reported.…”

Influence of Alkyl Substituent on Optical Properties of Carboxylate-Based Protic Ionic Liquids

“…Because of all these interactions including the strong hydrogen‐bonding capacity of the phenolate group even small traces of water makes the system very sensitive . Hence all the PILs were dried again in vacuum for 4 h prior to the UV experiments.…”

Revealing microheterogeneities and second order phase transitions in aqueous mixtures of 1-propoxypropan-2-ol at 298 K

“…When absorption spectra of a solute are obtained in different solvents, the position, intensity and shape of absorption bands change because of the different characteristics of the solvents under study. [64][65][66][67][68][69] The values are reported in Table S2 (ESI †) and plotted in Fig. [59][60][61][62][63] In order to achieve a better understanding about changes in molecular interactions for water-1-pp-2-ol mixtures, the Kamlet-Taft (p* and b) and the Reichardt parameters (E T (30) and E T (33)) have been determined over the whole range of mole fractions at 298.15 K. These four parameters were calculated for several mole fractions using the maximum absorbance wavenumber of suitable dyes, according to expressions described before.…”