Solvent effect on the dissociation constants and Soret band maxima of hematoporphyrin diacid

1995 ◽  
Vol 54 (2) ◽  
pp. 329-336 ◽  
Author(s):  
G. Móger
Keyword(s):  
Solvent Effect ◽  
Dissociation Constants ◽  
Soret Band

Solvent effect on the dissociation of p-nitroanilinium ion in glycerol–water media at 25 °C

1984 ◽  
Vol 62 (11) ◽  
pp. 2245-2248
Author(s):  
Amrita Lal De ◽  
Tapas Kumar De
Keyword(s):  
Solvent Effect ◽  
Dissociation Constants ◽  
Mixed Solvents ◽  
Individual Species ◽  
Aqueous Mixtures ◽  
Free Energies ◽  
Monohydric Alcohol ◽  
Glycerol Water ◽  
Alcohol Water ◽  
The Individual

Thermodynamic dissociation constants (sK) of p-nitroanilinium ion (BH+) have been determined at 25 °C in aqueous mixtures of 10, 30, 50, 70, and 90 wt.% of glycerol (GL) by spectrophotometric measurements. Standard free energies, [Formula: see text], of p-nitroaniline (B) from water to mixed solvents have been evaluated from the measurement of solubilities at 25 °C. p(sK) values decrease with increase in mol% of GL and pass through a minimum and then increase very slowly. The solvent effect on the dissociation, δ(ΔG0) = 2.303RT [p(sK)N – p(wK)N] has been discussed in terms of the standard free energies of transfer [Formula: see text] from water to aqueous mixtures of GL of the uncharged base (B), the hydrochloride of the base (BHCl), hydrochloric acid (HCl), and also in terms of the individual species involved in the dissociation process. The solvent effect in trihydric alcohol – water (GL + H2O) system has been compared with those in dihydric alcohol – water (ethylene glycol + water) and monohydric alcohol – water (ethanol + water) systems available from literature. The much less solvent effect in GL + H2O has been primarily attributed to the contrasting nature of interaction of H+ and of partially charged H atoms of—NH3+ group in BH+ compared to those in other two solvent systems.

Monoclonal Antibodies as New Macromolecular Hosts for Porphyrins

1992 ◽  
Vol 277 ◽  
Author(s):  
Akira Harada ◽  
Kazutake Okamoto ◽  
Hiroyuki Fukushima ◽  
Keizou Shiotsuki ◽  
Mikiharu Kamachi
Keyword(s):  
Monoclonal Antibodies ◽  
Dissociation Constants ◽  
Soret Band ◽  
Keyhole Limpet Hemocyanin ◽  
Poly Ethylene Glycol ◽  
Spleen Cells ◽  
Large Shift ◽  
Cotton Effects ◽  
Quantitative Analyses ◽  
Poly Ethylene

ABSTRACTMonoclonal antibodies against meso-tetrakis(4-carboxyphenyl porphine)(TCPP) were prepared by immunizing Balb/c mice with TCPP bound keyhole limpet hemocyanin covalently and fusing the spleen cells with myeloma cells by using poly(ethylene glycol). The antibodies bind TCPP strongly with the dissociation constants of 10−6−2.5 × 10−7 M. One of the antibodies causes a large shift of the Soret band of TCPP to a longer wavelength and large induced Cotton effects(ICD) on TCPP. Quantitative analyses of the binding of TCPP to the antibody by ICD show that not only one-to-one binding but two-to one(binding site: TCPP) binding occurs in excess of the antibody over TCPP.

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.

Solvent Effect on the Hammett Reaction Constant of Substituted Benzoic Acids

1993 ◽  
Vol 46 (1) ◽  
pp. 31 ◽  
Author(s):  
H Bartnicka ◽  
I Bojanowska ◽  
MK Kalinowski
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
Dissociation Constants ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
P Values ◽  
Reaction Constant ◽  
Substituted Benzoic Acids ◽  
Reaction Constants ◽  
Solvent Acidity

Potentiometric titration has been used to measure dissociation constants of 13 monosubstituted benzoic acids in nitromethane, benzonitrile , acetonitrile , propylene carbonate, acetone, N,N-dimethylformamide, dimethyl sulfoxide, methanol and formamide. The reaction constants of the Hammett equation were found to depend on the solvent acidity and basicity expressed by the α and β parameters of Kamlet and Taft. The p values determined earlier in water and ethanol also obey this rule.

Studies of the dissociation of 2,4,6-trinitrophenol in aqueous mixtures of methanol and ethanol at 25 °C

1985 ◽  
Vol 63 (11) ◽  
pp. 3129-3132 ◽  
Author(s):  
A. L. De ◽  
A. K. Atta
Keyword(s):  
Acetic Acid ◽  
Benzoic Acid ◽  
Solvent Effect ◽  
Spectrophotometric Method ◽  
Dissociation Constants ◽  
Dispersion Interaction ◽  
Organic Component ◽  
Aqueous Mixtures ◽  
Dispersion Interactions ◽  
The Difference

Thermodynamic dissociation constants (sK)m of 2,4,6-trinitrophenol have been determined at 25 °C in aqueous mixtures containing 30, 50, 70, and 90% by weight of methanol and 30, 50, 70, 90, and 95% by weight of ethanol by spectrophotometric method. Solvent effect on the dissociation of the acid: δ(ΔG0) = 2.303RT[p(sK)N − p(wK)N] shows an unusual behaviour, the value decreases and passes through a minimum and ultimately becomes positive as the proportion of organic component in the solvent is progressively increased. The results have been compared with those of other uncharged acids like acetic acid, benzoic acid available from literature. The difference of behaviour (minimum characteristic in δ(ΔG0) curve) has been attributed to very strong dispersion interaction of trinitrophenolate anion with the organic component of the solvent. The overall behaviour of this acid indicates that solvent effect is an involved process being guided by electrostatic and dispersion interactions besides relative solvent basicities.

Empirical method for consideration of solvent effect on the dissociation constants of carboxylic acids

2008 ◽  
Vol 44 (1) ◽  
pp. 52-61 ◽  
Author(s):  
Yu. E. Zevatskii ◽  
D. V. Samoilov
Keyword(s):  
Solvent Effect ◽  
Carboxylic Acids ◽  
Dissociation Constants ◽  
Empirical Method

Spectrophotometric study of the dissociation of p-nitroanilinium ion in a binary aqueous-dipolar aprotic solvent system (H2O + acetonitrile) at 25 °C: effect of the solvent

1984 ◽  
Vol 62 (9) ◽  
pp. 1776-1779
Author(s):  
A. L. De ◽  
T. K. De
Keyword(s):  
Solvent Effect ◽  
Dissociation Constants ◽  
Spectrophotometric Study ◽  
Solvent System ◽  
Individual Species ◽  
Aqueous Mixtures ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Aqueous Mixture ◽  
The Individual

Thermodynamic dissociation constants (SK) of p-nitroanilinium ion (BH+) have been determined at 25 °C in aqueous solutions containing 20, 40, 60, and 80 wt% acetonitrile (ACN) by spectrophotometric measurements. Standard Gibbs energies of transfer, [Formula: see text] (B) of p-nitroaniline (B) from water to other solvents have been evaluated from the measurement of solubilities at 25 °C. Solvent effect on the dissociation of the acid (BH+), δ(ΔG0) = 2.303RT[p(sK) − p(wK], results in a characteristic minimum with a change in the solvent composition. The result in this protic – dipolar aprotic mixture (H2O + ACN) has been compared with that in aqueous mixture of protic solvent (H2O + ethylene glycol) available from literature. The solvent effect has been discussed in terms of the standard Gibbs energies of transfer [Formula: see text], from water to aqueous mixtures of organic co-solvent of the uncharged base (B), the hydrochloride of the base (BHCl), and hydrochloric acid (HCl) and also in terms of the individual species involved in the dissociation process. The results indicate that solvent effect on dissociation is an involved process, guided by the combined effects of various types of solute–solvent interactions of the Brønsted acid and its conjugate base in addition to the relative solvent basicities.

Solvent effect in dissociation of substituted benzenesulphonamides in dimethylformamide, dimethyl sulphoxide, and acetonitrile

1984 ◽  
Vol 49 (11) ◽  
pp. 2593-2601 ◽  
Author(s):  
Miroslav Ludwig ◽  
Oldřich Pytela ◽  
Miroslav Večeřa
Keyword(s):  
Factor Analysis ◽  
Solvent Effect ◽  
General Formula ◽  
Potentiometric Titration ◽  
Dissociation Constants ◽  
Dimethyl Sulphoxide ◽  
Short Cycle ◽  
Testing Method

Dissociation constants of fifteen substituted arenesulphonamides of general formula XC6H4.SO2NH2 (or X2C6H3SO2NH2) have been measured by potentiometric titration in dimethylformamide, dimethyl sulphoxide, and acetonitrile. The Hammett substitution correlations have been calculated and interpreted for these media. The pKHA values measured and the results published earlier for methanol, ethanol, and water have been treated by multiple linear regresion using the published set of the parameters characterizing solvents and by factor analysis using the short cycle and the target testing method.

Solvent Effect on the Dissociation Constants of Aliphatic Carboxylic Acids

1991 ◽  
Vol 44 (8) ◽  
pp. 1077 ◽  
Author(s):  
H Bartnicka ◽  
I Bojanowska ◽  
MK Kalinowski
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
General Formula ◽  
Carboxylic Acids ◽  
Potentiometric Titration ◽  
Dissociation Constants ◽  
Solvent Polarity ◽  
P Values ◽  
Reaction Constants ◽  
Aliphatic Carboxylic Acids

Dissociation constants of 10 aliphatic carboxylic acids, of general formula R-COOH, were measured by potentiometric titration in acetonitrile, propylene carbonate, acetone, N,N- dimethylformamide and dimethyl sulfoxide. The p* reaction constants of the Taft equation were found to depend on the solvent polarity, whereas the influence of the Lewis basicity and acidity is negligible. The p* values determined earlier in water, methanol and nitromethane also fulfil this rule.

Sign in / Sign up

Export Citation Format

Share Document