Interactions In Ternary Solutions Research Articles

Investigations to Explore Molecular Interactions and Sweetness Response of Polyhydroxy Compounds with Amino Acids in Aqueous Systems

In conjunction with the development of people's living standards, the modern world demands good-quality food such as sweets, candies, chocolates, diet drinks, beverages, and so on, but because of obesity and other health issues people concentrate more on sugar-free or low-calorie products. Polyols are such a kind of food with desirable qualities, and they play a role in controlling the blood glucose level in diabetic patients. The density (ρ) and sound speed (u) of sugar alcohol in water and in (0.02, 0.04, and 0.06) mol kg-1l-arginine solutions at different temperatures (293.15-318.15 K) and atmospheric pressure were measured by using Anton Paar DSA5000M. Experimental density and sound velocity data were further used to compute volumetric and acoustic parameters such as apparent molar volume (ØV), partial molar volume (Ø V 0), compressibility (Ø k 0), expansibility (Ø E 0), and so on. The positive trends of apparent molar volume (Ø V ), and partial molar volume Ø V 0), values indicate strong hydrophilic interactions in ternary solutions. These interactions give a complete picture about solvation behavior, the effect of temperature, and hydrogen bonding present among (galactitol + l-arginine) mixtures. The apparent specific volume values were calculated, and it was found that these values of the investigated mixtures lie on the borderline with the reported values of sweeteners. This study may offer a new vision in elucidation of mechanistic modifications between sugar alcohol, amino acid, and their mode of interactions.

1,2,4-Triazol-1-ium-p-chloro-phenacylids in hydroxyl binary solvent mixtures. Computational and solvatochromic study

Triazolium ylids and their derivatives are used as precursors for a great number of compounds in pharmaceutical and industrial fields. Triazolium ylids are amphiliophilic compounds with separated charges on positive nitrogen belonging to heterocycle and on negatively charged carbon, named carbanion and covalently bonded to the positive nitrogen. These substances are used in situ. Consequently, their interactions with the liquids, especially with water and primary alcohols are very important. The data regarding solute-solvent interactions in ternary solutions of two 4-aryl-1,2,4-trazol-1-ium-p-chloro-phenacylids were obtained by solvatochromism and by quantum chemical computations. New information about the ternary solution anisotropy and about the potential energy of molecular interactions of the type of ylid-water and ylid-ethanol are given in this study.

Trimethylamine N-oxide Counteracts Urea Denaturation by Inhibiting Protein-Urea Preferential Interaction.

Osmolytes are small organic molecules that can modulate the stability and function of cellular proteins by altering the chemical environment of the cell. Some of these osmolytes work in conjunction, via mechanisms that are poorly understood. An example is the naturally occurring protein-protective osmolyte trimethylamine N-oxide (TMAO) that stabilizes cellular proteins in marine organisms against the detrimental denaturing effects of another naturally occurring osmolyte, urea. From a computational standpoint, our understanding of this counteraction mechanism is hampered by the fact that existing force fields fail to capture the correct balance of TMAO and urea interactions in ternary solutions. Using molecular dynamics simulations and Kirkwood-Buff theory of solutions, we have developed an optimized force field that reproduces experimental Kirkwood-Buff integrals. We show through the study of two model systems, a 15-residue polyalanine chain and the R2-fragment (273GKVQIINKKLDL284) of the Tau protein, that TMAO can counteract the denaturing effects of urea by inhibiting protein-urea preferential interaction. The extent to which counteraction can occur is seen to depend heavily on the amino acid composition of the peptide.

Interaction energy in pairs of phthalazinium dibenzoylmethylid (PDBM)–protic solvent molecules estimated in the limits of the cell ternary solution model, by spectral means

The dipolar compound Phthalazinium-dibenzoylmethylid (PDBM) was used as spectrally active molecule in order to analyze the molecular interactions in ternary solutions containing at least one protic solvent. In PDBM+protic solvent (1)+aprotic solvent (2) ternary solutions, PDBM can be involved both in universal and specific interactions reflected in solvatochromic effects. The protic solvent (or the solvent with the higher electric permittivity) was considered as being active from the interactions point of view. The content of the first solvation sphere of the studied ylid has been established on the basis of the statistical cell model of ternary solutions. The active solvent molecules are dominant in the first solvation sphere of the PDBM molecules. The difference between the interaction energies in the PDBM–active solvent (1) and PDBM–inactive solvent (2) molecular pairs has been determined for three binary solvents water+ethanol (W+E), propionic acid+chloroform (PA+C) and octanol+1,2 dichloroethane (O+DCE). The hydrogen bond formation energy of the PDBM–protic solvent complex has been estimated in the binary solvents PA+C and O+DCE containing one protic (PA and O, respectively) and one aprotic solvent with close electro-optical parameters refractive index and electric permittivity of the components.

Studies on Solution Properties of Some Amino Acids in Aqueous Mixture of Catechol

Apparent molar volumes, V φ, viscosities, η, and apparent isentropic compressibilities, K φ, of glycine, L-alanine, L-valine and L-leucine in 0.05, 0.10, 0.15 mol Kg−1 catechol solutions have been determined at 298.15 K by measuring the densities, viscosities and ultrasonic speed of the above solutions respectively. The standard partial molar volumes, , standard volumes of transfer, , standard partial isentropic compressibilities, , transfer compressibilities, , hydration number, N w , of the amino acids have been calculated for investigating the various interactions in the ternary solutions. The linear correlation of partial molar volume and viscosity B-coefficients with increasing number of carbon atoms in the alkyl chain have been used to explain the contribution of charged end group (, COO−) and the ‒CH2 group to . The results have been interpreted in the light of solute-solvent interactions in the mixed ternary solutions.

Study on the intermolecular interactions in rifampicin ternary solutions — Calculation of microscopic parameters of rifampicin molecules

The nature of solute–solvent interactions in ternary solutions of rifampicin–water–ethanol was investigated by means of electronic absorption spectra recorded in visible and in ultraviolet range respectively. Measurements upon the frequency in the absorption band maxima were carried out, the mathematical interpretation of the solvent spectral shifts, on the basis of Bakhshiev's theory, leading to the emphasizing of orientation and dynamic forces. Molecular orbital modeling applied by means of specialized soft, resulted in the computational approach of rifampicin dipole moment and intramolecular hydrogen bond lengths, evidencing also four metastable conformers.

Molecular interactions of selected amino acids in aqueous resorcinol solutions: volumetric, viscometric and acoustic studies

Apparent molar volumes, Vo,, viscosities, η, and apparent molal isentropic compressibility, K o, , of glycine, L-alanine, L-valine and L-leucine in 0.05, 0.10, 0.15 mol kg -1 resorcinol solutions have been determined at 298.15 K by measuring the densities, viscosities and ultrasonic speed of the above solutions respectively. The apparent molar volumes at infinite dilution, V o 0 , standard volumes of transfer, ΔtrV o 0 , apparent molar isentropic compressibilities, K o 0 , transfer compressibilities, ΔtrKo 0 , hydration number, N w , of the amino acids have been calculated for investigating the various interactions in the ternary solutions. The linear correlation of partial molar volume and viscosity Bcoefficients with increasing number of carbon atoms in the alkyl chain have been utilized to calculate the contributions of charged end groups (NH 3 + ,COO - ), CH 2 - groups and other alkyl chains of amino acids to V o 0 . The results have been interpreted in terms of ion-ion, ion-polar, hydrophilic-hydrophilic and hydrophobichydrophobic group interactions in the mixed ternary solutions.

Viscometric and thermodynamic studies of interactions in ternary solutions containing sucrose and aqueous alkali metal halides at 293·15, 303·15 and 313·15 K

Viscosities and densities of sucrose in aqueous alkali metal halide solutions of different concentrations in the temperature range 293.5 to 313.15 K have been measured. Partial molar volumes at infinite dilution (V 02 ) of sucrose determined from apparent molar volume (φ v ) have been utilized to estimate partial molar volumes of transfer (V 02,tr ) for sucrose from water to alkali metal halide solutions. The viscosity data of alkali metal halides in purely aqueous solutions and in the presence of sucrose at different temperatures (293.15, 303.15 and 313.5 K) have been analysed by the Jones-Dole equation. The nature and magnitude of solute-solvent and solute-solute interactions have been discussed in terms of the values of limiting apparent molar volume (φ 0 v ), slope (S v ) and coefficients of the Jones-Dole equation. The structure-making and structure-breaking capacities of alkali metal halides in pure aqueous solutions and in the presence of sucrose have been ascertained from temperature dependence ofφ 0 v .

Ultrasonic studies of interactions in ternary solutions containing sorbitol and sodium carboxylate solution at 308 K

Ultrasonic velocities and densities of sorbitol in aqueous alkali carboxylate solutions of different concentrations: 0.5 M, 1.0 M and 1.5 M at 308 K have been measured. Adiabatic compressibility,βs; apparent molar volume, Φv, apparent molar compressibility,\(\Phi _{\beta _s } \), and hydration number, Hn were deduced from their measured data. Results show that there are short range weak interactions.