Solvation Thermodynamics in Aqueous Solutions

Solvation thermodynamics examines the energetic changes that occur when a solute is transferred from the gas phase or another medium into water. Key contributions to the overall free energy of solvation arise from enthalpic and entropic components: the enthalpy reflects the balance of favourable solute–solvent interactions and the disruption of solvent–solvent networks, while the entropy encompasses changes in solvent structuring and solute mobility. In aqueous systems, the strong polarity and hydrogen-bonding capacity of water render solvation particularly complex, with effects ranging from the hydration of small ions to the binding of large biomolecules. Models for predicting solvation properties span continuum approaches, which treat water as a uniform dielectric medium, to explicit-solvent simulations that account for individual water molecule dynamics. Advances in computational methods have improved the accuracy of solvation free energies, aiding the design of pharmaceuticals, catalysts and materials. Understanding how factors such as ionic size, charge distribution and temperature influence hydration energetics is critical for fields as diverse as environmental chemistry, biophysics and process engineering. Rigorous thermodynamic characterisation underpins our ability to predict solubility, reaction equilibria and binding affinities in aqueous media.

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Solvation Thermodynamics in Aqueous Solutions publication trend

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Technical terms

Solvation free energy: The change in Gibbs free energy when a solute is transferred from a reference state into aqueous solution.

Hydration enthalpy: The enthalpic component of solvation free energy, arising from solute–solvent interaction and solvent rearrangement.

Continuum solvent model: A computational approach that represents the solvent as a uniform dielectric medium rather than as discrete molecules.

Explicit solvation: A modelling technique in which individual solvent molecules are included to capture specific interactions and dynamics.

Entropy of solvation: The change in entropy associated with the ordering or disordering of solvent and solute upon solvation.

References

1. Predicting accurate absolute binding energies in aqueous solution: thermodynamic considerations for electronic structure methods. Physical Chemistry Chemical Physics (2015).
2. Absolute ion hydration enthalpies and the role of volume within hydration thermodynamics. RSC Advances (2017).
3. Beyond Continuum Solvent Models in Computational Homogeneous Catalysis. Topics in Catalysis (2021).