Thermo-solvatochromism in binary mixtures of water and ionic liquids: on the relative importance of solvophobic interactions.

The thermo-solvatochromism of 2,6-dibromo-4-[(E)-2-(1-methylpyridinium-4-yl)ethenyl] phenolate, MePMBr(2), has been studied in mixtures of water, W, with ionic liquids, ILs, in the temperature range of 10 to 60 degrees C, where feasible. The objectives of the study were to test the applicability of a recently introduced solvation model, and to assess the relative importance of solute-solvent solvophobic interactions. The ILs were 1-allyl-3-alkylimidazolium chlorides, where the alkyl groups are methyl, 1-butyl, and 1-hexyl, respectively.

Solvatochromism in binary mixtures: first report on a solvation free energy relationship between solvent exchange equilibrium constants and the properties of the medium.

We have employed UV-vis spectroscopy in order to investigate details of the solvation of six solvatochromicindicators, hereafter designated as "probes", namely, 2,6-diphenyl-4-(2,4,6-triphenylpyridinium-1-yl) phenolate(RB); 4-[(E)-2-(1-methylpyridinium-4-yl)ethenyl] phenolate, MePM; 1-methylquinolinium-8-olate, QB;2-bromo-4-[(E)-2-(1-methylpyridinium-4-yl)ethenyl] phenolate, MePMBr, 2,6-dichloro-4-(2,4,6-triphenylpyridinium-1-yl) phenolate (WB); and 2,6-dibromo-4-[(E)-2-(1-methylpyridinium-4-yl)ethenyl] phenolate,MePMBr2, respectively. These can be divided into three pairs, each includes two probes of similar p kappa(a) in water and different lipophilicity. Solvation has been studied in binary mixtures, BMs, of water, W, with 12protic organic solvents, S, including mono- and bifunctional alcohols (2-alkoxyethanoles, unsaturated and chlorinated alcohols).

First study on the thermo-solvatochromism in aqueous 1-(1-Butyl)-3-methylimidazolium tetrafluoroborate: a comparison between the solvation by an ionic liquid and by aqueous alcohols.

The thermo-solvatochromic behaviors of 2,6-diphenyl-4-(2,4,6-triphenylpyridinium-1-yl) phenolate, RB; 2,6-dichloro-4-(2,4,6-triphenylpyridinium-1-yl) phenolate, WB; 2,6-dibromo-4-[( E)-2-(1-methylpyridinium-4-yl)ethenyl] phenolate, MePMBr 2; 2,6-dibromo-4-[( E)-2-(1-n-octylpyridinium-4-yl)ethenyl] phenolate, OcPMBr 2, have been investigated in binary mixtures of the ionic liquid, IL, 1-(1-butyl)-3-methylimidazolium tetrafluorborate, [BuMeIm][BF 4], and water (W), in the temperature range from 10 to 60 degrees C. Plots of the empirical solvent polarities, E T (probe) in kcal mol (-1), versus the mole fraction of water in the binary mixture, chi w, showed nonlinear, i.e.

Thermosolvatochromism of merocyanine polarity indicators in pure and aqueous solvents: relevance of solvent lipophilicity.

The following novel solvatochromic probes were synthesized: 2,6-dibromo-4-[(E)-2-(1-alkylpyridinium-4-yl)ethenyl] phenolate, where the alkyl groups are methyl, n-butyl, n-hexyl, and n-octyl, respectively. Solvatochromism of three of these probes (C(1), C(4), and C(8)) was studied in 36 protic and aprotic solvents. A modified linear solvation energy relationship has been applied to the data obtained at 25 degrees C.