Hydrogen Bonding of Neutral Species in the Gas Phase: The Missing Link

Marco, Josefina; Orza, J.M.; Notario, Rafael; Abboud, José‐Luis M.

doi:10.1021/ja00098a067

Cited by 27 publications

(38 citation statements)

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“…As an example, we consider TFE and propanone, for which the 1:1 hydrogen bond association constant in the gas phase is 53 10. We can deduce the corresponding values in other solvents from eq 7, the coefficients in Table 1, and values of α H 2 = 0.567 for TFE and β H 2 = 0.497 for propanone.…”

Section: Resultsmentioning

confidence: 99%

Hydrogen Bonding between Solutes in Solvents Octan-1-ol and Water

et al. 2010

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1:1 Equilibrium constants, K, for the association of hydrogen bond bases and hydrogen bond acids have been determined using solvent octan-1-ol at 298 K for 30 acid-base combinations. The values of K are much smaller than those found for aprotic, rather non-polar solvents. It is shown that the log K values can satisfactorily be correlated against αH2*βH2, where αH2 and βH2 are the 1:1 hydrogen bond acidities and basicities of solutes. The slope of the plot, 2.938, is much smaller than those for log K values in the non-polar organic solvents previously studied. An analysis of literature data on 1:1 hydrogen bonding in water yields a negative slope for a plot of log K against αH2*βH2, thus showing how the use of very strong hydrogen bond acids and bases does not lead to larger values of log K for 1:1 hydrogen bonding in water. It is suggested that for simple 1:1 association between mono-functional solutes in water, log K cannot be larger than about −0.1 log units. Descriptors have been obtained for the complex between 2,2,2-trifluoroethanol and propanone, and used to analyze solvent effects on the two reactants, the complex, and the complexation constant.

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Section: Resultsmentioning

confidence: 99%

Hydrogen Bonding between Solutes in Solvents Octan-1-ol and Water

et al. 2010

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“…Marco et al, 1994). Additionally, it was found from gas-phase hydrogen bonding data between the fluoro-alcohols and various ketonic and enolic (phenolic, in particular, such as the enol form of the Schiff base used in this investigation) compounds that the third equilibrium ( K , ) may be ignored (Abraham, 1993;Marco et al, 1994), because the equilibrium constant for hydrogen bonds between fluoro-alcohols and ketones is so much greater in comparison to that between the fluoro-alcohols and the phenolic compounds. This results in a model based on only two equilibrium constants where zK, zE, and zKH are the true concentrations of the keto and enol tautomers of the Schiff base, respectively, and the keto hydrogen bonded complex.…”

Section: K + H -K H E + H @ E H H + H~h H (3)mentioning

confidence: 86%

“…The equilibrium constant for the Schiff base keto tautomer/cosolvent hydrogen bonded complex (K,) was assumed to be equal to the gas-phase equilibrium constant for the same hydrogen bond donors with similar ketone compounds. These were obtained from the literature (Marco et al, 1994) and are given in Table 5. The gas-phase data were given for 25°C and were corrected to experimental conditions of 35°C using gas-phase enthalpy of formation literature data for the appropriate cosolvent/ketone complex (Kivinen and Murto, 1969;Tucker and Christian, 1976).…”

Section: 20mentioning

confidence: 99%

Cosolvent tuning of tautomeric equilibrium in supercritical fluids

et al. 1997

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“…We have recently examined the case of 1:1 hydrogen bonding complexes of neutral species in the gas phase 10 and found that the quantitative pattern of structural effects of donors and acceptors on their stability is the same as found in solvents such as tetrachloromethane or cyclohexane. All these results taken together strongly suggest that for many processes taking place in environments in which bulk water and/or other species leading to strong charge-dispersal through hydrogen bonding are absent, gas-phase thermodynamic data are possibly the choice descriptors of structural effects.…”

Section: IImentioning

confidence: 94%