Specific solvent effects on the thermal denaturation of ribonuclease. Effect of dimethyl sulfoxide and p-dioxane on thermodynamics of denaturation

Biochemistry ◽  
1980 ◽  
Vol 19 (19) ◽  
pp. 4534-4538 ◽  
Author(s):  
A. L. Jacobson ◽  
C. L. Turner
Keyword(s):  
Dimethyl Sulfoxide ◽  
Solvent Effects ◽  
Thermal Denaturation

The application of the Hammett equation to 13C N.M.R. spectrometry. IV. Solvent effects

1982 ◽  
Vol 35 (1) ◽  
pp. 21 ◽  
Author(s):  
DAR Happer
Keyword(s):  
Carbon Tetrachloride ◽  
Dimethyl Sulfoxide ◽  
Solvent Effects ◽  
Aqueous Ethanol ◽  
Chemical Shifts ◽  
Hammett Equation ◽  
Solvent Dependence ◽  
Ethanol Ethanol ◽  
Vinyl Group

The chemical shifts for Cβ of the vinyl group of styrene and 16 of its meta-or para-substituted derivatives have been measured in seven solvents: 75% aqueous ethanol, ethanol, dimethyl sulfoxide, acetone, deuterochloroform, carbon tetrachloride and benzene. Attempts have been made to correlate the data by means of the Hammett equation, discrepancies being discussed in terms of solvent dependence of σ and p.

Solute–solvent effects in the dissociation of thymolsulfonephthalein (an uncharged acid) in aqueous mixtures of acetonitrile (ACN), urea, and dimethyl sulfoxide (DMSO)

1986 ◽  
Vol 64 (8) ◽  
pp. 1521-1526 ◽  
Author(s):  
A. L. De ◽  
A. K. Atta
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
Solvent Effects ◽  
Mixed Solvent ◽  
Dissociation Constants ◽  
Aqueous Mixtures ◽  
Solvent Interactions ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Solvent Systems

The thermodynamic first dissociation constants, [Formula: see text] of thymolsulfonephthalein (H2A), an uncharged acid, have been determined at 25 °C in aqueous mixtures of 10, 30, 50, 70, and 80 wt% acetonitrile (ACN), 11.52, 20.31, 29.64, and 36.83 wt% urea, 20, 40, 60, and 80 wt% dimethyl sulfoxide (DMSO) by spectrophotometric measurements. The solvent effect represented by ∂(ΔG0) = 2.303RT[p(sK)N − p(wK)N] is found to increase in ACN + H2O system as mol% ACN increases in the solvent. In contrast, the corresponding values in urea + H2O as well as DMSO + H2O solvent systems decrease with increase in proportion of organic component in the solvent, the decrease being sharp in urea + H2O. The results have been discussed in terms of the standard Gibbs energies of transfer of H+ from water to the mixed solvent, [Formula: see text] and the relative values of the standard Gibbs energies of transfer of HA−, [Formula: see text] and of [Formula: see text] in all the solvent systems. The overall dissociation behaviour of the acid (H2A) is found to be dictated by the specific solute-solvent interactions of the species participating in the dissociation equilibria.

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