A table of thermodynamic functions of ionic hydration

Benjamin, L.; Gold, Victor

doi:10.1039/tf9545000797

Cited by 53 publications

(24 citation statements)

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“…The equations of motion were integrated using the velocity Verlet algorithm 230 with a time step of 2 fs. The water molecules (both MM and QM regions) were kept entirely rigid by means of three distance constraints, enforced using the M-RATTLE procedure 231,232 with a relative geometric tolerance of 10 8 .…”

Section: Computational Detailsmentioning

confidence: 99%

“…These quantities can be easily calculated from each other [see Eqs. (8) and (9) in this article] but, due to the electroneutrality constraint, they encompass the constant C • wat which cannot be determined on the sole basis of experimental measurements. For this reason, the three above quantities have been termed elusive.…”

Section: Introductionmentioning

confidence: 99%

“…4.5.1 in Ref. 1), involving, e.g., setting G • H + ,wat to zero, [6][7][8][9][10] setting the formation parameters of the aqueous proton to those of the gaseous proton, 10,11 setting the formation parameters of the aqueous proton to zero, [10][11][12][13] or setting V • H + ,wat to zero (electrochemical series of redox potentials). The quantitative predictive power of these scales in the context of experimental (i.e., electroneutral) processes is unaffected, but the arbitrariness of the anchoring limits their use for intuitive reasoning in the context of single-ion properties and processes.…”

Section: Introductionmentioning

confidence: 99%

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Absolute proton hydration free energy, surface potential of water, and redox potential of the hydrogen electrode from first principles: QM/MM MD free-energy simulations of sodium and potassium hydration

Hofer

Hünenberger

2018

The Journal of Chemical Physics

104

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The absolute intrinsic hydration free energy G • H + ,wat of the proton, the surface electric potential jump χ • wat upon entering bulk water, and the absolute redox potential V • H + ,wat of the reference hydrogen electrode are cornerstone quantities for formulating single-ion thermodynamics on absolute scales. They can be easily calculated from each other but remain fundamentally elusive, i.e., they cannot be determined experimentally without invoking some extra-thermodynamic assumption (ETA). The Born model provides a natural framework to formulate such an assumption (Born ETA), as it automatically factors out the contribution of crossing the water surface from the hydration free energy. However, this model describes the short-range solvation inaccurately and relies on the choice of arbitrary ion-size parameters. In the present study, both shortcomings are alleviated by performing first-principle calculations of the hydration free energies of the sodium (Na + ) and potassium (K + ) ions. The calculations rely on thermodynamic integration based on quantum-mechanical molecular-mechanical (QM/MM) molecular dynamics (MD) simulations involving the ion and 2000 water molecules. The ion and its first hydration shell are described using a correlated ab initio method, namely resolution-of-identity second-order Møller-Plesset perturbation (RIMP2). The next hydration shells are described using the extended simple point charge water model (SPC/E). The hydration free energy is first calculated at the MM level and subsequently increased by a quantization term accounting for the transformation to a QM/MM description. It is also corrected for finite-size, approximate-electrostatics, and potentialsummation errors, as well as standard-state definition. These computationally intensive simulations provide accurate first-principle estimates for G • H + ,wat , χ • wat , and V • H + ,wat , reported with statistical errors based on a confidence interval of 99%. The values obtained from the independent Na + and K + simulations are in excellent agreement. In particular, the difference between the two hydration free energies, which is not an elusive quantity, is 73.9 ± 5.4 kJ mol 1 (K + minus Na + ), to be compared with the experimental value of 71.7 ± 2.8 kJ mol 1 . The calculated values of G • H + ,wat , χ • wat , and V • H + ,wat ( 1096.7 ± 6.1 kJ mol 1 , 0.10 ± 0.10 V, and 4.32 ± 0.06 V, respectively, averaging over the two ions) are also in remarkable agreement with the values recommended by Reif and Hünenberger based on a thorough analysis of the experimental literature ( 1100 ± 5 kJ mol 1 , 0.13 ± 0.10 V, and 4.28 ± 0.13 V, respectively). The QM/MM MD simulations are also shown to provide an accurate description of the hydration structure, dynamics, and energetics. Published by AIP Publishing.

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Section: Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Absolute proton hydration free energy, surface potential of water, and redox potential of the hydrogen electrode from first principles: QM/MM MD free-energy simulations of sodium and potassium hydration

Hofer

Hünenberger

2018

The Journal of Chemical Physics

104

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“…This has been defined (3, 7, 11) in terms of the standard enthalpies of the complexes trans-[Rh(en),LXIn+, the enthalpies increasing along the series X = C1 < Br < I, and being measured relative to that of trans- (Y = C1 and Br) by subtracting the enthalpy contribution due to the different hydration enthalpies of the free halides. In order to obtain values consistent with our earlier data we have used the older values (14) for the enthalpies of hydration of the halides rather than the newer ones (15) is quite different from that of the i.k.t.e. discussed above, although it is likely that the i.k.t.e.…”

Section: The Thermodynamic Trans-effect Of Hydroxidementioning

confidence: 88%

The trans-Effect in Octahedral Complexes. VI. Base Hydrolysis of trans-Hydroxybromo and trans-Hydroxychlorobis(ethylenediamine)-rhodium(III) Complexes

Poë¹,

Vuik²

1975

Can. J. Chem.

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ANTHONY POE and CAROL VUIK. Can. J. Chem. 53,1842Chem. 53, (1975 (2) to provide a single measure of the intrinsic kinetic trans-effect (i.k.t.e.) (3) of hydroxide in such complexes. Since the i.k.t.e. of any ligand is obtained in such a way that it should be independent of the particular interchange reaction used to measure it we now report kinetic studies of the base hydrolysis of the analogous hydroxybromo and hydroxychloro complexes which confirm this independence for the transhydroxy complexes. The second-order term in the rate equation for reaction of trans-[Rh(en),-(OH)I]+ (not previously found in such transdiacido complexes (4, 5)) has also been found in these reactions. ExperimentalThe complexes tran~-[Rh(en)~X,1CIO~ (X = CI or Br) were prepared by standard methods (6, 7). Satisfactory analyses were obtained for carbon, nitrogen, and hydrogen and the electronic spectra (Table 1) of aqueous solutions of the complexes were in satisfactory agreement with published results (6, 8) although there are some slight differences in the extinction coefficients, particularly of the highest energy band of the dibromo complex (cf: E = 31 000 cm-I I mol-I (8)). Two previously unreported higher energy bands for the dichloro complex are also listed. Solutions of the trans-hydroxyhalogeno complexes were obtained by dissolving ca. 1 mmol of the trans-dihalogeno complexes in the minimum of hot water and refluxing with I cc of 0.1 M perchloric acid and 10 cc of cc1. 0.1 M silver perchlorate (1 equiv.) for 200 min (X = CI) or 40min (X = Br). Curved rate plots were obtained when the base hydrolyses of such solutions were studied spectrophotometrically and it was evident that the solutions contained mixtures of complexes. Pure solutions of the hydroxyhalogeno complexes were obtained by pressure chromatography through a 12cm-long column of Dowex 50W (100-200 mesh). Elution with 0.5 M sodium perchlorate Can. J. Chem. Downloaded from www.nrcresearchpress.com by 54.244.106.145 on 05/11/18For personal use only.

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“…5 Absolute values of C were calculated preserving the assumption of Latimer,6 that c(Na+) 91.5 kcal. Introduction of the correction 1.89 kcal for the shift in standard states 1 gives a value c(Na+) =89.61 kcal for unit activity of sodium ion which was accepted as a base for calculating the values of c for other ions.…”

mentioning

confidence: 99%

Erratum: Spectroscopic Evidence for Triatomic Nitrogen in Solids at Very Low Temperature

Peyron

Hörl

Brown

et al. 1959

The Journal of Chemical Physics

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A table of thermodynamic functions of ionic hydration

Abstract: A table of heats, entropies and Gibbs free energies of hydration at 25°C of simple ions, relative to hydrogen, has been compiled from recent thermodynamic data.1

Cited by 53 publications

References 0 publications

Absolute proton hydration free energy, surface potential of water, and redox potential of the hydrogen electrode from first principles: QM/MM MD free-energy simulations of sodium and potassium hydration

Absolute proton hydration free energy, surface potential of water, and redox potential of the hydrogen electrode from first principles: QM/MM MD free-energy simulations of sodium and potassium hydration

The trans-Effect in Octahedral Complexes. VI. Base Hydrolysis of trans-Hydroxybromo and trans-Hydroxychlorobis(ethylenediamine)-rhodium(III) Complexes

Erratum: Spectroscopic Evidence for Triatomic Nitrogen in Solids at Very Low Temperature

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