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MeCOCH=C(Me)O anion


Reaction thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: John E. Bartmess

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Individual Reactions

C5H7O2- + Hydrogen cation = Acetylacetone

By formula: C5H7O2- + H+ = C5H8O2

Quantity Value Units Method Reference Comment
Deltar1438. ± 8.8kJ/molG+TSTaft and Bordwell, 1988gas phase; at 330K: neutral enol/keto ratio should be 8:1 ( Strohmeier and Höhne, 1952)
Deltar1438. ± 9.6kJ/molG+TSCumming and Kebarle, 1978gas phase; At 500K: neutral enol/keto ratio is 1.7:1, Folkendt, Weiss-Lopez, et al., 1989. «DELTA»H=-4.7 kcal/mol, enol favored. Carbonyls anti in anion, via calc: Irikura, 1999
Quantity Value Units Method Reference Comment
Deltar1409. ± 8.4kJ/molIMRETaft and Bordwell, 1988gas phase; at 330K: neutral enol/keto ratio should be 8:1 ( Strohmeier and Höhne, 1952)
Deltar1408. ± 8.4kJ/molIMRECumming and Kebarle, 1978gas phase; At 500K: neutral enol/keto ratio is 1.7:1, Folkendt, Weiss-Lopez, et al., 1989. «DELTA»H=-4.7 kcal/mol, enol favored. Carbonyls anti in anion, via calc: Irikura, 1999

Gas phase ion energetics data

Go To: Top, Reaction thermochemistry data, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: John E. Bartmess

Electron affinity of neutral species

EAneutral (eV) Method Reference Comment
2.64 ± 0.19D-EACumming and Kebarle, 1978At 500K: neutral enol/keto ratio is 1.7:1, Folkendt, Weiss-Lopez, et al., 1989. «DELTA»H=-4.7 kcal/mol, enol favored. Carbonyls anti in anion, via calc: Irikura, 1999
2.52 ± 0.13IMRBSharpe and Richardson, 1991MP2/6-31+G*: EA 2.8 eV, in sickle geometry, 99IRI

Protonation reactions

C5H7O2- + Hydrogen cation = Acetylacetone

By formula: C5H7O2- + H+ = C5H8O2

Quantity Value Units Method Reference Comment
Deltar1438. ± 8.8kJ/molG+TSTaft and Bordwell, 1988gas phase; at 330K: neutral enol/keto ratio should be 8:1 ( Strohmeier and Höhne, 1952)
Deltar1438. ± 9.6kJ/molG+TSCumming and Kebarle, 1978gas phase; At 500K: neutral enol/keto ratio is 1.7:1, Folkendt, Weiss-Lopez, et al., 1989. «DELTA»H=-4.7 kcal/mol, enol favored. Carbonyls anti in anion, via calc: Irikura, 1999
Quantity Value Units Method Reference Comment
Deltar1409. ± 8.4kJ/molIMRETaft and Bordwell, 1988gas phase; at 330K: neutral enol/keto ratio should be 8:1 ( Strohmeier and Höhne, 1952)
Deltar1408. ± 8.4kJ/molIMRECumming and Kebarle, 1978gas phase; At 500K: neutral enol/keto ratio is 1.7:1, Folkendt, Weiss-Lopez, et al., 1989. «DELTA»H=-4.7 kcal/mol, enol favored. Carbonyls anti in anion, via calc: Irikura, 1999

References

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Taft and Bordwell, 1988
Taft, R.W.; Bordwell, F.G., Structural and Solvent Effects Evaluated from Acidities Measured in Dimethyl Sulfoxide and in the Gas Phase, Acc. Chem. Res., 1988, 21, 12, 463, https://doi.org/10.1021/ar00156a005 . [all data]

Strohmeier and Höhne, 1952
Strohmeier, W.; Höhne, I., Keto-Enol-Umwandlung des Acetylacteons in Gaszustand, Z. Naturfor., 1952, 7B, 184. [all data]

Cumming and Kebarle, 1978
Cumming, J.B.; Kebarle, P., Summary of gas phase measurements involving acids AH. Entropy changes in proton transfer reactions involving negative ions. Bond dissociation energies D(A-H) and electron affinities EA(A), Can. J. Chem., 1978, 56, 1. [all data]

Folkendt, Weiss-Lopez, et al., 1989
Folkendt, M.M.; Weiss-Lopez, B.E.; Chauvel, J.P., Jr.; True, N.S., Gas-Phase 1H NMR Studies of Keto-Enol Tautomerization of Acetylacetone, Methyl Acetoacetate, and Ethyl Acetoacetate, J. Phys. Chem., 1989, 89, 15, 3347, https://doi.org/10.1021/j100261a038 . [all data]

Irikura, 1999
Irikura, K.K., Acetylacetonate (acac) anion in the gas phase: predicted structures, vibrational spectra, and photodetachment energies, Int. J. Mass Spectrom., 1999, 187, 577-587, https://doi.org/10.1016/S1387-3806(98)14192-1 . [all data]

Sharpe and Richardson, 1991
Sharpe, P.; Richardson, D.E., Metal-Ligand Bond Energies and Solvation Energies for Gas-Phase Transition Metal Tris(acetylacetonate) Complexes and their Negative Ions, J. Am. Chem. Soc., 1991, 113, 22, 8339, https://doi.org/10.1021/ja00022a021 . [all data]


Notes

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