نتایج جستجو برای: solvation
تعداد نتایج: 5929 فیلتر نتایج به سال:
The solubility of solutes in mixed solvents depends primarily on the solvation of the solutes or their constituent ions by the components of the solvent mixtures. Complications may arise if different crystal solvates are formed or if solute-solute interactions are appreciable. In their absence the standard molar Gibbs energies of solution measure the corresponding quantities of solvation, ASOIV...
In this paper, we investigate the solvation of coffee ingredients including caffeine, gallic acid as representative for phenolic compounds and quercetin as representative for flavonoids in aqueous mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate [C2mim][OAc] at various concentrations. Due to the anisotropy of the solutes we show that classical Kirkwood-Buff theory is not appropr...
Selected theoretical methods, basis sets and solvation models have been tested in their ability to predict P NMR chemical shifts of large phosphorous-containing molecular systems in solution. The most efficient strategy was found to involve NMR shift calculations at the GIAO-MPW1K/ 6-311++G(2d,2p)//MPW1K/6-31G(d) level in combination with a dual solvation model including the explicit considerat...
To improve the description of solvation thermodynamics of biomolecules, we report here the dependence of solvation on the curvature and surface charge of positively charged solutes in water based on extensive molecular dynamics simulations analyzed using the two-phase thermodynamic method. At a surface charge of +0.4e, the compensating forces of favorable electrostatic stabilization and entropi...
In this study, we assess the influence of solvation on the accuracy and reliability of isotropic nuclear magnetic shielding calculations for amino acids in comparison to experimental data. We focus particularly on the performance of solvation methods for different protonation states, as biological molecules occur almost exclusively in aqueous solution and are subject to protonation with pH. We ...
Since the salting-in agents guanidinium chloride, urea, and lithium perchlorate increase the surface tension of water, the salting-in phenomenon does not reflect easier cavity formation in water. Therefore, these salting-in agents must be directly contributing to the solvation of a solute such as benzene in water, probably by a direct solvation interaction. The increased surface-tension effects...
The linear response (LR) approximation, which predicts identical relaxation rates from all nonequilibrium initial conditions that relax to the same equilibrium state, underlies dominant models of how solvation influences chemical reactivity. We experimentally tested the validity of LR for the solvation that accompanies partial electron transfer to and from a monatomic solute in solution. We pho...
Data have been assembled on the enthalpies of solvation of 373 compounds in water and 138 compounds in 1-octanol. It is shown that an Abraham solvation equation with five descriptors can be used to correlate the experimental solvation enthalpies to within standard deviations of 3.68 kJ/mol (water) and 2.66 kJ/mol (1-octanol). The derived correlations provide very accurate mathematical descripti...
Selected theoretical methods, basis sets and solvation models have been tested in their ability to predict (31)P NMR chemical shifts of large phosphorous-containing molecular systems in solution. The most efficient strategy was found to involve NMR shift calculations at the GIAO-MPW1K/6-311++G(2d,2p)//MPW1K/6-31G(d) level in combination with a dual solvation model including the explicit conside...
This paper describes a generalized method to establish the values of the five solvation parameters of solutes, which reflect, together with the five solvation parameters of solvents, the intermolecular forces involved in solutions and in some biological phenomena. The tool applied for this purpose is a simplified molecular topology (SMT), which principally takes into account, for each atom of a...
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