Thermodynamics Research Today is a free monthly online journal that collates and summarizes the latest research about Thermodynamics, including details on enthalpy, entropy, energy transitions.

Thermodynamic aspects of solubility process of some sulfonamides.

Perlovich GL, Ryzhakov AM, Strakhova NN, Kazachenko VP, Schaper KJ, Raevsky OA

Department of Computer-Aided Molecular Design, Institute of Physiologically Active Compounds, Russian Academy of Sciences, 142432 Chernogolovka, Russia; Institute of Solution Chemistry, Russian Academy of Sciences, 153045 Ivanovo, Russia.

The thermodynamic aspects of solubility process of sulfonamides with the general structures C(6)H(5)-SO(2)NH-C(6)H(4)-R (R=4-NO(2); 4-Cl) and 4-NH(2)-C(6)H(4)-SO(2)NH-C(6)H(4)-R (R=4-NO(2); 4-CN; 4-Cl; 4-OMe; 4-C(2)H(5)) in water, phosphate buffer with pH 7.4 and n-octanol (as phases modeling various drug delivery pathways) were studied using the isothermal saturated method.

Published 30 August 2010 in J Pharm Biomed Anal.
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Articles on Thermodynamics published 30 August 2010:

Poly(A) tail affects equilibrium and thermodynamic behavior of tobacco etch virus mRNA with translation initiation factors eIF4F, eIF4B and PABP.   Biochim Biophys Acta.

We have investigated the effects of poly(A)-tail on binding of eIF4F, eIF4B and PABP with tobacco etch virus (TEV) IRES RNA. The fluorescence anisotropy data showed that the addition of poly(A)(20) increases the binding affinity of eIF4F.4B and eIF4F.PABP complexes to IRES RNA ~2- and 4-fold, respectively. However, the binding affinity of eIF4F with PK1 was enhanced ~11-fold with the addition of PABP, eIF4B, and poly(A)(20) together. Whereas, poly(A)(20) alone increases the binding affinity of ... [Abstract] [Full-text]

Thermodynamic and kinetic study of chiral separations of coumarin-based anticoagulants on derivatized amylose stationary phase.   J Chromatogr A, 1217(38): 5901-5912.

Thermodynamic and kinetic studies are performed on amylose derivatized with tris-(3,5-dimethylphenyl carbamate) stationary phase for the chiral separation of coumarin-based anticoagulants. Polar-organic eluents that contain acetonitrile as bulk solvent with modifiers such as methanol, i-butanol, t-butanol, and tetrahydrofuran are used in the study. Temperature is varied from 5 to 45 degrees C at constant pressure of 1500psi. In general, both retention and enantioselectivity decrease as the ... [Abstract] [Full-text]

Articles on Thermodynamics published 27 August 2010:

CO and O(2) Binding to Pseudo-tetradentate Ligand-Copper(I) Complexes with a Variable N-Donor Moiety: Kinetic/Thermodynamic Investigation Reveals Ligand-Induced Changes in Reaction Mechanism.   J Am Chem Soc.

The kinetics, thermodynamics, and coordination dynamics are reported for O(2) and CO 1:1 binding to a series of pseudo-tetradentate ligand-copper(I) complexes ((D)LCu(I)) to give Cu(I)/O(2) and Cu(I)/CO product species. Members of the (D)LCu(I) series possess an identical tridentate core structure where the cuprous ion binds to the bispicolylamine (L) fragment. (D)L also contains a fourth variable N-donor moiety {D = benzyl (Bz); pyridyl (Py); imidazolyl (Im); dimethylamino (NMe(2)); ... [Abstract] [Full-text]

Articles on Thermodynamics published 25 August 2010:

X-ray Crystal Structures of [XeF][MF(6)] (M = As, Sb, Bi), [XeF][M(2)F(11)] (M = Sb, Bi) and Estimated Thermochemical Data and Predicted Stabilities for Noble-Gas Fluorocation Salts using Volume-Based Thermodynamics.   Inorg Chem.

The crystal structures of the xenon(II) salts, [XeF][SbF(6)], [XeF][BiF(6)], and [XeF][Bi(2)F(11)], have been determined for the first time, and those of XeF(2), [XeF][AsF(6)], [XeF][Sb(2)F(11)], and [XeF(3)][Sb(2)F(11)] have been redetermined with greater precision at -173 degrees C. The Bi(2)F(11)(-) anion, which has a structure analogous to those of the As(2)F(11)(-) and Sb(2)F(11)(-) anions, has been structurally characterized by single crystal X-ray diffraction for the first time as its ... [Abstract] [Full-text]

Thermodynamic Stability of Neutral and Anionic PFOS: A Gas-Phase, n-Octanol, and Water Theoretical Study.   J Phys Chem A.

The thermodynamic stability of the 89 isomers of the eight-carbon-atom compound perfluorooctane sulfonate (PFOS) in their neutral and anionic forms has been studied in the gas phase, n-octanol, and water using density functional theory (B3LYP/6-311+G(d,p)). The gas-phase calculations are compared with previous semiempirical and partial ab initio studies; the calculations in water and n-octanol are reported for the first time. The results obtained indicate that the thermodynamic stability ... [Abstract] [Full-text]

Towards a thermodynamic definition of efficacy in partial agonism. II: The thermodynamics of efficacy and ligand proton transfer in a G protein-coupled receptor of the rhodopsin class.   Biochem Pharmacol.

The thermodynamic binding profiles of agonist and antagonist complexes of the 4-hydroxypropanolamine partial agonist, prenalterol, on the chronotropic adrenergic response in guinea-pig right atria were determined over a 15 degrees C temperature range. The tissue response was compared with data on the ethanolamine agonist, isoprenaline, given by binding studies in a number of rat tissues. Utilising the residue conservatism surrounding the known active conformers bound to either of two aspartate ... [Abstract] [Full-text]

Articles on Thermodynamics published 24 August 2010:

Thermodynamics of Hydrogen Adsorption on Metal-Organic Frameworks.   Chemphyschem.

Interaction between adsorbed hydrogen and the coordinatively unsaturated Mg(2+) and Co(2+) cationic centres in Mg-MOF-74 and Co-MOF-74, respectively, was studied by means of variable-temperature infrared (VTIR) spectroscopy. Perturbation of the H(2) molecule by the cationic adsorbing centre renders the H--H stretching mode IR-active at 4088 and 4043 cm(-1) for Mg-MOF-74 and Co-MOF-74, respectively. Simultaneous measurement of integrated IR absorbance and hydrogen equilibrium pressure for ... [Abstract] [Full-text]

Thermodynamic Characterization of ppGpp Binding to EF-G or IF2 and of Initiator tRNA Binding to Free IF2 in the Presence of GDP, GTP, or ppGpp.   J Mol Biol.

In addition to their natural substrates GDP and GTP, the bacterial translational GTPases initiation factor (IF) 2 and elongation factor G (EF-G) interact with the alarmone molecule guanosine tetraphosphate (ppGpp), which leads to GTPase inhibition. We have used isothermal titration calorimetry to determine the affinities of ppGpp for IF2 and EF-G at a temperature interval of 5-25 degrees C. We find that ppGpp has a higher affinity for IF2 than for EF-G (1.7-2.8 muM K(d)versus 9.1-13.9 muM K(d) ... [Abstract] [Full-text]

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