Accurate Evaluation of Charge Asymmetry in Aqueous Solvation
| Autor: | Igor S. Tolokh, Abhishek Mukhopadhyay, Alexey V. Onufriev |
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| Rok vydání: | 2015 |
| Předmět: |
Models
Molecular media_common.quotation_subject Static Electricity education FOS: Physical sciences Asymmetry Small Molecule Libraries Computational chemistry Physics - Chemical Physics Electric field parasitic diseases Materials Chemistry Water model Molecule Physics::Chemical Physics Physical and Theoretical Chemistry media_common Chemical Physics (physics.chem-ph) Ions Aqueous solution Chemistry Chemical polarity Solvation Water Biomolecules (q-bio.BM) Charge (physics) Surfaces Coatings and Films Solutions Quantitative Biology - Biomolecules Models Chemical Solubility Chemical physics FOS: Biological sciences Thermodynamics Algorithms |
| Zdroj: | The Journal of Physical Chemistry B. 119:6092-6100 |
| ISSN: | 1520-5207 1520-6106 |
| Popis: | Charge hydration asymmetry (CHA)-a characteristic dependence of hydration free energy on the sign of the solute charge-quantifies the asymmetric response of water to electric field at microscopic level. Accurate estimates of CHA are critical for understanding hydration effects ubiquitous in chemistry and biology. However, measuring hydration energies of charged species is fraught with significant difficulties, which lead to unacceptably large (up to 300%) variation in the available estimates of the CHA effect. We circumvent these difficulties by developing a framework which allows us to extract and accurately estimate the intrinsic propensity of water to exhibit CHA from accurate experimental hydration free energies of neutral polar molecules. Specifically, from a set of 504 small molecules we identify two pairs that are analogous, with respect to CHA, to the K(+) /F(-) pair-a classical probe for the effect. We use these "CHA-conjugate" molecule pairs to quantify the intrinsic charge-asymmetric response of water to the microscopic charge perturbations: the asymmetry of the response is strong, ∼50% of the average hydration free energy of these molecules. The ability of widely used classical water models to predict hydration energies of small molecules correlates with their ability to predict CHA. |
| Databáze: | OpenAIRE |
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