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  • 1
    Electronic Resource
    Electronic Resource
    Solvent effects on infrared spectroscopic and calorimetric characteristics of aliphatic ketones in binary solvent mixtures (1998)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 283-289 
    Details
    ISSN: 0894-3230
    Keywords: calorimetry ; IR spectra ; ketones ; solvation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Solution enthalpies of n-hexane, acetone, butan-2-one and octan-2-one in a series of tetrachloromethane-acetonitrile mixtures and the carbonyl stretching absorption frequencies in the IR spectra of these ketones were determined. It was found that over the whole range of concentrations (varying from neat tetrachloromethane up to neat acetonitrile) the solvation enthalpy of these compounds can be obtained additively from the contributions of the alkyl and carbonyl fragments. The solvent effect on the solvation enthalpy of the carbonyl group was found to be satisfactorily correlated with the corresponding IR frequency shifts of the C=O group. It was also found that the sensitivities of the carbonyl IR frequencies to the solvent composition are different for various ketones. From both IR and calorimetric data, the preferential solvation parameters were evaluated. The differences between the IR spectroscopic and calorimetric data are discussed. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Isotherm of water sorption by human serum albumin in dioxane: Comparison with calorimetric data (1995)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 8 (1995), S. 84-88 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dependence of the amount of water bound to human serum albumin (HSA) suspended in water-dioxane mixtures vs the equilibrium water concentration in the liquid phase was determined by the Fisher method at 298 K. The Langmuir model was used in order to describe the isotherm of the sorption of water by HSA at low water concentrations in the solvent. The calculated equilibrium constant of water adsorption (3.8 ± 0.6 l mol-1) is in good agreement with the adsorption constant obtained earlier from calorimetric data. The comparison of the determined isotherm of water sorption by HSA with the reported enthalpies of suspension formation showed that at low water concentrations in the solvent, water sorption is the only process contributing to the heat effects of the formation of the ‘protein + liquid’ heterogeneous system. From this comparison, the enthalpy of water adsorption by HSA was evaluated as -11.9 ± 1.7 kJ mol-1. At higher water concentrations in the solvent the amount of water adsorbed by HSA increased considerably. This increase in the amount of water on HSA at water activities above 0.5 is assumed to be due to the enlargement of the protein surface area.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610080205
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  • 3
    Electronic Resource
    Electronic Resource
    Vapor sorption of organic compounds on human serum albumin (1997)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 10 (1997), S. 901-907 
    Details
    ISSN: 0894-3230
    Keywords: human serum albumin ; vapor sorption ; organic compounds ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: ---Sorption isotherms were measured for a series of organic compounds from the vapor phase on dried solid human serum albumin (HSA). Parameters of the Brunauer-Emmet-Teller (BET) isotherm were evaluated from experimental data. A nonlinear trend was observed between the volume of a filled ‘monolayer’ and the molar volume of organic compounds. The effective ‘monolayer’ volume quickly decreased with increase in sorbate molar volume. Larger molecules have less space available for sorption on solid HSA. This shows that the size of molecules is important factor determining the number of available places for sorption on HSA. The sorbate-protein interactions are sensitive also to the structural differences between n-and iso-isomeric sorbates. The Gibbs energy RTlnKR for the sorbate transfer from the gas phase standard state to the state to the state of an infinite by diluted sorbed compound (at zero sorbate activity) with uptake 1 mol kg-1 was calculated from the BET parameters. This Gibbs energy of the gas phase-protein phase transfer corresponds to the distribution coefficient KR similar to the Henry coefficient. A correlation was found between RTlnKR values and the molar volume of sorbates. As distinct from the behavior typical for organic solvents, larger molecules are more distributed to the gas phase in comparison with smaller compounds. The positive increment of a methylene group to the gas-protein transfer Gibbs energies was also estimated from data for aliphatic alcohols. This increment is higher than the analogous value evaluated from the Gibbs energies of hydration of the same alcohols. The sorption phenomenon was interpreted in terms of dissolution of organic compounds in the protein phase. It demonstrates a superficially repulsive effect for the organic molecules sorbed in solid HSA. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Hydrogen bonding in pure base media. Correlations between calorimetric and infrared spectroscopic data (1996)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 9 (1996), S. 241-251 
    Details
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The known correlations between calorimetric and IR spectroscopic data on hydrogen bonding were reinvestigated for hydrogen bond donors (AH) dissolved in pure bases (B). Ninety-five AH···B systems were considered for which the enthalpies of specific interaction due to hydrogen bonding AH···B (ΔHAH/Bsp.int., kJ mol-1), the weight centers of A-H stretching bands (v, cm-1) and their integral absorption coefficients (α, 104 cm mmol-1) had been measured. The relationships between ΔHAH/Bsp.int. and the parameters of the infrared absorption spectra [weight center shifts Δv and the changes in the square roots of α (Δα1/2)] were analyzed. It was found that the dependence of ΔHAH/Bsp.int. on Δα1/2 consists of two nearly parallel straight lines: the first (-ΔHAH/Bsp.int. = 12·0 Δα1/2 + 0·4) corresponds to water and the weak C(SINGLE BOND)H and O(SINGLE BOND)H H-bond donors (chloroethylenes, acetylenes acetonitrile, nitromethane, chloroform, o, o′-di-tert-butylphenol); the second (-ΔHAH/Bsp.int. = 12·1 Δα1/2 -4·2) corresponds to the stronger N(SINGLE BOND)H and O(SINGLE BOND)H H-bond donors (N-methylaniline, pyrrole, alcohols, phenol, carbon acids). Non-linear dependences of ΔHAH/Bsp.int. on Δv were obtained for all C(SINGLE BOND)H, N(SINGLE BOND)H and O(SINGLE BOND)H H-bond donors except water [-ΔHAH/Bsp.int. = 59·9 Δv/(Δv + 674)]. Enthalpies of specific interaction for water obey another dependence [-ΔHH2O/Bsp.int./2 = 28·5 Δv/(Δv + 269)]. The ΔHAH/Bsp.int. values can be estimated by the above correlations with an accuracy of ±3 to ±6 kJ mol-1. These relationships obtained for solutions of H-bond donors in pure bases differ from the well known dependences determined for the AH···B hydrogen bonding in carbon tetrachloride medium.
    Additional Material: 5 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Calorimetric study of human serum albumin in water-dioxane mixtures (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 251-253 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The calorimetric isotherm of water sorption by solid human serum albumin (HSA) was measured in water-dioxane mixtures. This isotherm has been successfully described at low water contents in the solvent within the framework of the presented model. The adsorption equilibrium constant and the monolayer formation energy were estimated from this model. The interaction enthalpies of solid HSA with the solvent in water-rich mixtures do not differ essentially from the solution enthalpy of HSA in water. This means that the solvent water content may be sufficient for the intermolecular interactions of HSA suspended in a water-organic mixture to be similar to those in aqueous protein solution.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610060409
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  • 6
    Electronic Resource
    Electronic Resource
    1-acetoxyvinyl phosphonates: Facile synthesis via catalytic acylation of dialkyl phosphites (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 3 (1992), S. 127-131 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new and facile method of synthesis of 1-acetoxyvinyl phosphonates (2) has been found. Dialkyl phosphites react readily with acetic anhydride in acetonitrile solution in the presence of catalysts to produce 2 and acylphosphonates (1) as a minor product. The most efficient catalysts are metal compounds of variable valency: iron(II), iron(III), and cobalt(II) chlorides. The same compounds catalyze transformation of 1 into 2 in an acetonitrile solution of acetic anhydride.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520030207
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