Heats of formation of ionic and neutral enols of acetaldehyde and acetone

Holmes, John L.; Lossing, F. P.

doi:10.1021/ja00373a058

Cited by 155 publications

(88 citation statements)

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“…about 1; (ls+l:). A value for I: (ls+l:), can, however, be derived from the shoulder at 9.18 eV, in good agreement with [4]. This shoulder has been reproduced several times and its intensity did not vary with decomposition temperature.…”

Section: Pm) the Observed Frequency Is Not Unexpected For A Corresposupporting

confidence: 70%

“…We note in this context that the resonance energy of iso-x-electronic vinylamine cations is estimated experimentally to be z 1 eV 1:9]. The PE transition 0 therefore most likely corresponds to l$+l; Its vibrational activity due to the already discussed in-plane skeletal change indicates a considerable non-adiabaticity which might be the reason for the low ion production efficiency noted in [4].…”

Section: Pm) the Observed Frequency Is Not Unexpected For A Correspomentioning

confidence: 74%

“…A recent investigation of the appearence potential of If using mass-spectrometric techniques has shown a low cross section for ionization over the initial portion of the ion production efficiency curve [4]. Small Franck-Condon (FC) factors for an adiabatic process l + l + were made responsible for this observation, and rationalized through the theoretical prediction [7] that -contrary to the most stable conformation for 1 (i.e.…”

Section: Pm) the Observed Frequency Is Not Unexpected For A Correspomentioning

confidence: 99%

“…-The details of the PE setup have been described in [5]. 1 was prepared by pyrolysis of cyclobutanol 3 [4] in a Pt/Rh-tube (a = 0.9 mm) containing a silica capillary insert and attached directly to the target chamber. This silica insert proved to be crucial since pyrolysis in the hot metal tube alone led exclusively to 2 and ethylene.…”

mentioning

confidence: 99%

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Molecular Ions of Transient Species: Vinyl‐Alcohol Cation

Albrecht

Allan

Haselbach

et al. 1984

Helvetica Chimica Acta

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SummaryVinyl alcohol 1 was prepared by thermolysis of cyclobutanol and its photoelectron spectrum was determined. 1; = 9.18 eV and It = 9.52 eV were found, the vibrational progression ( i j = 1400 cm-') for this lowest energy transition 1(X)+ l+(X) indicating significant skeletal changes in the ion. The question of the relative stability of the syn (1;)-us. anti-ions (1;) is discussed in the light of theoretical calculations. The energy of the second n-state of 1' is estimated at 13.6-14.1 eV above the ground state of 1.

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Section: Pm) the Observed Frequency Is Not Unexpected For A Corresposupporting

confidence: 70%

Section: Pm) the Observed Frequency Is Not Unexpected For A Correspomentioning

confidence: 74%

Section: Pm) the Observed Frequency Is Not Unexpected For A Correspomentioning

confidence: 99%

mentioning

confidence: 99%

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Molecular Ions of Transient Species: Vinyl‐Alcohol Cation

Albrecht

Allan

Haselbach

et al. 1984

Helvetica Chimica Acta

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“…[2,3] The experimental energy difference between the two forms varies from about 12 [2,4] to 13.9 kcal mol À1 , both for the gas phase and in solution, and this indicates similar water solvation for both isomers. The keto-enol equilibrium is also shifted far to the keto side (keto/enol ratio % 10 11 [5,6] ) in both environments.…”

Section: Introductionmentioning

confidence: 91%

Ab Initio Molecular Dynamics Study of the Keto–Enol Tautomerism of Acetone in Solution

et al. 2006

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We have studied the keto-enol interconversion of acetone to understand the mechanism of tautomerism relevant to numerous organic and biochemical processes. Applying the ab initio metadynamics method, we simulated the keto-enol isomerism both in the gas phase and in the presence of water. For the gas-phase intramolecular mechanism we show that no other hydrogen-transfer reactions can compete with the simple keto-enol tautomerism. We obtain an intermolecular mechanism and remarkable participation of water when acetone is solvated by neutral water. The simulations reveal that C deprotonation is the kinetic bottleneck of the keto-enol transformation, in agreement with experimental observations. The most interesting finding is the formation of short H-bonded chains of water molecules that provide the route for proton transfer from the carbon to the oxygen atom of acetone. The mechanistic picture that emerged from the present study involves proton migration and emphasizes the importance of active solvent participation in tautomeric interconversion.

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