An AM1 study of the preferential solvation of ammonium ion in ammonia—water mixtures

Galera, S.; Lluch, J. M. O.; Oliva, A.; Bertrán, Juan

doi:10.1016/0166-1280(88)80382-8

Cited by 35 publications

(7 citation statements)

References 30 publications

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“…In one study, hydrogen bonding interactions between water molecules and protonated amines were ~alculated,2~ and another study considered solvation of the ammonium ion by water and ammonia. 25 In each case, hydrogen bond energies were quite close to available experimental values. Stewart's PM3 method, which uses a reparameterized AM1 Hamiltonian, also reasonably predicts hydrogen bonds!…”

Section: Introductionsupporting

confidence: 71%

Hydration of small anions: Calculations by the AM1 semiempirical method

1991

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The AM1 semiempirical molecular orbital method has been used to calculate successive heats of hydration of small anions, including hydride, hydroxide, and the halogen ions, for cluster sizes up to 11 water molecules surrounding the central anion. Heats of hydration agree with available experimental data to within a few kcal/ mol. Structures, however, do not always agree well with available ab initio calculations on clusters with one or two water molecules. The results indicate that the AM1 semiempirical technique applied to finite-sized clusters must be used with caution in understanding how hydration affects the chemical reactions of anions.

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Section: Introductionsupporting

confidence: 71%

Hydration of small anions: Calculations by the AM1 semiempirical method

1991

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“…Even though ammonia binds to the ammonium cation better than water does, 59 the high concentration of water in the atmosphere drives the mass action effect to produce fully hydrated ammonium cation clusters. Table 3 As displayed in Tables 2 and 3, the G3 values for ∆G°for formation of NH 4 + (H 2 O) n are -14.3, -8.9, -6.2, and -5.4 kcal/ mol for n ) 1-4 waters.…”

Section: Resultsmentioning

confidence: 99%

Comparison of Model Chemistry and Density Functional Theory Thermochemical Predictions with Experiment for Formation of Ionic Clusters of the Ammonium Cation Complexed with Water and Ammonia; Atmospheric Implications

2005

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The G2, G3, CBS-QB3, and CBS-APNO model chemistry methods and the B3LYP, B3P86, mPW1PW, and PBE1PBE density functional theory (DFT) methods have been used to calculate deltaH(o) and deltaG(o) values for ionic clusters of the ammonium ion complexed with water and ammonia. Results for the clusters NH4(+) (NH3)n and NH4(+) (H2O)n, where n = 1-4, are reported in this paper and compared against experimental values. Agreement with the experimental values for deltaH(o) and deltaG(o) for formation of NH4(+) (NH3)n clusters is excellent. Comparison between experiment and theory for formation of the NH4(+) (H2O)n clusters is quite good considering the uncertainty in the experimental values. The four DFT methods yield excellent agreement with experiment and the model chemistry methods when the aug-cc-pVTZ basis set is used for energetic calculations and the 6-31G* basis set is used for geometries and frequencies. On the basis of these results, we predict that all ions in the lower troposphere will be saturated with at least one complete first hydration shell of water molecules.

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“…PS has been investigated with a wide variety of experimental methods (electrochemical [10] and thermodynamic [11] measurements, solvatochromic effects on UV/Vis or fluorescence spectra, [12±15] circular dichroism, [16] IR, [11c, 17±19] and NMR [chemical shift [20] or line-width [21] measurements]) and with theoretical methods (semiempirical [22] or Monte Carlo [23] calculations on simple solvation models, and molecular dynamics simulations [24±26] ). The relationship between PS and the microscopic characteristics of the solvation shell has been described by means of various theoretical models, such as the stepwise solvent exchange, [27,28] competitive preferential solvation, [29] and quasi-lattice quasi-chemical [30] theories, and preferential solvation isotherms.…”

Section: Introductionmentioning

confidence: 99%

Preferential Solvation of Organic Species in Binary Solvent Mixtures Probed by Intermolecular1H NOESY NMR Spectroscopy

et al. 1999

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The preferential solvation of neutral and ionic organic species (phenol, nitroanilines, N-methylbutyramide, 1,4-dioxane, acetate and tetraalkylammonium ions) in binary solvent mixtures (aqueous CH 3 CN, DMSO, EtOH, 1-PrOH, CH 3 CON(CH 3 ) 2 ; CH 2 Cl 2 /Et 2 O; 1,4-dioxane/benzene; cyclohexane/THF) has been investigated through the analysis of the relative intensities of intermolecular 1 H NOESY cross-peaks according to Macura ± Ernst theory. Observed preferential solvation is discussed in terms of the strength of individual solute ± solvent interactions, hydrophobic interactions in water-rich mixtures, and microheterogeneity in the mixed medium.

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An AM1 study of the preferential solvation of ammonium ion in ammonia—water mixtures

Cited by 35 publications

References 30 publications

Hydration of small anions: Calculations by the AM1 semiempirical method

Hydration of small anions: Calculations by the AM1 semiempirical method

Comparison of Model Chemistry and Density Functional Theory Thermochemical Predictions with Experiment for Formation of Ionic Clusters of the Ammonium Cation Complexed with Water and Ammonia; Atmospheric Implications

Preferential Solvation of Organic Species in Binary Solvent Mixtures Probed by Intermolecular1H NOESY NMR Spectroscopy

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