1,3-Cyclopentanedione
- Formula: C5H6O2
- Molecular weight: 98.0999
- IUPAC Standard InChI: InChI=1S/C5H6O2/c6-4-1-2-5(7)3-4/h1-3H2
- IUPAC Standard InChIKey: LOGSONSNCYTHPS-UHFFFAOYSA-N
- CAS Registry Number: 3859-41-4
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Other names: 1,3-Cyclopentadione; cyclopentane-1,3-dione
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Gas phase ion energetics 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 as indicated in comments:
B - John E. Bartmess
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 9.46 ± 0.05 | PE | Houk, Davis, et al., 1973 | LLK |
| 9.53 | PE | Gleiter, Hofmann, et al., 1980 | Vertical value; LLK |
De-protonation reactions
C5H5O2- + =
By formula: C5H5O2- + H+ = C5H6O2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 333.5 ± 2.1 | kcal/mol | G+TS | Mishima, Matsuoka, et al., 2004 | gas phase; Calc: keto form of acid more stable.; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 326.5 ± 2.0 | kcal/mol | IMRE | Mishima, Matsuoka, et al., 2004 | gas phase; Calc: keto form of acid more stable.; B |
References
Go To: Top, 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.
Houk, Davis, et al., 1973
Houk, K.N.; Davis, L.P.; Newkome, G.R.; Duke, R.E., Jr.; Nauman, R.V.,
Photoelectron spectroscopy of cyclic β-diketones their enolone tautomers,
J. Am. Chem. Soc., 1973, 95, 8364. [all data]
Gleiter, Hofmann, et al., 1980
Gleiter, R.; Hofmann, P.; Schang, P.; Sieber, A.,
The orbital sequence in cyclic 1,3-diketones,
Tetrahedron, 1980, 36, 655. [all data]
Mishima, Matsuoka, et al., 2004
Mishima, M.; Matsuoka, M.; Lei, Y.X.; Rappoport, Z.,
Gas-phase acidities of disubstituted methanes and of enols of carboxamides substituted by electron-withdrawing groups,
J. Org. Chem., 2004, 69, 18, 5947-5965, https://doi.org/10.1021/jo040196b
. [all data]
Notes
Go To: Top, Gas phase ion energetics data, References
- Symbols used in this document:
ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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