Solute/solvent interactions and their empirical determination by means of solvatochromic dyes

Abstract

Abstract

Solvent effects on aromatic nucleophilic substitutions. Part 6. Kinetics of the reaction of 1‐chloro‐2, 4‐dinitrobenzene with piperidine in binary solvent mixtures

“…Particularly detailed studies have been carried out with one of the simplest systems of ANS: the reaction of l-chloro-2,4-dinitrobenzene (2,4-DNCB) with piperidine (PIP). In connection with this, we have studied the influence of solvent effects on the reaction rate in 13 aprotic solvents with a dielectric constant range of 43 units," showing that kinetic data are well correlated by the Dimroth-Reichardt solvent polarity scale ET (30). The correlation is remarkably good (~0 .…”

“…The next question is to determine if for all the (ApS , + toluene) binary mixtures under consideration the ET (30) parameter is available to reflect the experimentally observed solvent effects on the present reaction. In that context we examined (a) the (ApS, + toluene) binary solvent mixtures studied, at fixed concentrations, and (b) the (ApS,+toluene) binary solvent mixtures at all concentrations studied, including in this case the data from the literature corresponding to pure aprotic solvents.…”

“…Visible spectra of sample solutions in 10 mm cell were recorded at 15 and 40 "C by using a Perkin-Elmer Model 124 UV-VIS spectrophotometer and a Zeiss PMQ 3 UV-VIS spectrophotometer equipped with a data-acquisition system and a thermostated cell holder. Temperatures were measured in the cell and were accurate to within kO.1 "C. The ET (30) values were determined from the longest-wavelength UV-VIS absorption band of Reichardt's betaine dye and were calculated according to the equation ET (30) [kcal mol-'I = hcvN=2.859 x 1 0 -j~ [cm- '1 …”

Solvatochromic absorbance probe behavior within 1-butyl-3-methylimidazolium hexafluorophosphate+propylene carbonate: Preferential solvation or solvent–solvent interaction?

“…2,6-Diphenyl-4-(2,4,6-triphenyl-N-pyridino)phenolate (Reichardt's dye 30) exhibits an unusually high-solvatochromic absorbance band shift [33][34][35]. The lowest energy intramolecular charge-transfer absorption band of the Reichardt's dye is hypsochromically shifted by ca.…”

Solvatochromic polarity parameters for binary mixtures of 1-butyl-3-methylimidazolium acetate with water, methanol, and dimethylsulfoxide

“…Different solvatochromic parameters determined from the data on N T E PHYSICAL CHEMISTRY OF SOLUTIONS the location of bands in the absorption (emission) spectra of standard compounds (solvatochromic indicators), in which the energy of electron transitions is determined by certain properties of a medium, are now most often used for the quantitative characterization of such properties [20][21][22]. This is especially true of the Dimroth-Reichardt energy E T (30), determined for the electron transition of N-4-oxy-3,5-diphenyl-2,4,6-triphenylpyridinium betaine (Reichardt betaine) and now serving as a generalized medium polarity characteristic, and the Kamlet-Taft solvatochromic parameters α, β, and π* [20][21][22][23][24][25][26][27], which reflect the electron-accepting and electron-donating ability of a solvent and its polarity/polarizability, respectively. The latter are widely used to describe the effect a solvent has on the properties and reactivity of dissolved compounds using the principle of the linear solvation energy relationships (LSER) in the Kamlet-Taft formalism [26]:…”