Water, being the universal solvent, acts as a competing agent in fundamental processes, such as folding, aggregation or biomolecular recognition. A molecular understanding of hydrophobic hydration is of central importance to understanding the subtle free energy differences, which dictate function. Ab initio and classical molecular dynamics simulations yield two distinct hydration water populations in the hydration shell of solvated tert-butanol noted as "HB-wrap" and "HB-hydration2bulk". The experimentally observed hydration water spectrum can be dissected into two modes, centered at 164 and 195 cm(-1) . By comparison to the simulations, these two bands are attributed to the "HB-wrap" and "HB-hydration2bulk" populations, respectively. We derive a quantitative correlation between the population in each of these two local water coordination motifs and the temperature dependence of the solvation entropy. The crossover from entropy to enthalpy dominated solvation at elevated temperatures, as predicted by theory and observed experimentally, can be rationalized in terms of the distinct temperature stability and thermodynamic signatures of "HB-wrap" and "HB-hydration2bulk".

Wrapping up Hydrophobic Hydration: Locality Matters / Conti Nibali V.; Pezzotti S.; Sebastiani F.; Galimberti D.R.; Schwaab G.; Heyden M.; Gaigeot M.-P.; Havenith M.. - In: THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS. - ISSN 1948-7185. - STAMPA. - 11:(2020), pp. 4809-4816. [10.1021/acs.jpclett.0c00846]

Wrapping up Hydrophobic Hydration: Locality Matters

Sebastiani F.;
2020

Abstract

Water, being the universal solvent, acts as a competing agent in fundamental processes, such as folding, aggregation or biomolecular recognition. A molecular understanding of hydrophobic hydration is of central importance to understanding the subtle free energy differences, which dictate function. Ab initio and classical molecular dynamics simulations yield two distinct hydration water populations in the hydration shell of solvated tert-butanol noted as "HB-wrap" and "HB-hydration2bulk". The experimentally observed hydration water spectrum can be dissected into two modes, centered at 164 and 195 cm(-1) . By comparison to the simulations, these two bands are attributed to the "HB-wrap" and "HB-hydration2bulk" populations, respectively. We derive a quantitative correlation between the population in each of these two local water coordination motifs and the temperature dependence of the solvation entropy. The crossover from entropy to enthalpy dominated solvation at elevated temperatures, as predicted by theory and observed experimentally, can be rationalized in terms of the distinct temperature stability and thermodynamic signatures of "HB-wrap" and "HB-hydration2bulk".
11
4809
4816
Conti Nibali V.; Pezzotti S.; Sebastiani F.; Galimberti D.R.; Schwaab G.; Heyden M.; Gaigeot M.-P.; Havenith M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2158/1288142
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