Pyrazine
- Formula: C4H4N2
- Molecular weight: 80.0880
- IUPAC Standard InChI: InChI=1S/C4H4N2/c1-2-6-4-3-5-1/h1-4H
- IUPAC Standard InChIKey: KYQCOXFCLRTKLS-UHFFFAOYSA-N
- CAS Registry Number: 290-37-9
- 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: p-Diazine; Paradiazine; Piazine; 1,4-Diazabenzene; 1,4-Diazine
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Reaction thermochemistry data
Go To: Top, References, Notes
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
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
RCD - Robert C. Dunbar
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.
Individual Reactions
C4H3N2- + =
By formula: C4H3N2- + H+ = C4H4N2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 392.6 ± 2.5 | kcal/mol | TDEq | Meot-ner and Kafafi, 1988 | gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 383.50 ± 0.40 | kcal/mol | N/A | Wren, Vogelhuber, et al., 2012 | gas phase; B |
| ΔrG° | 383.1 ± 2.0 | kcal/mol | TDEq | Meot-ner and Kafafi, 1988 | gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B |
3 +
=
By formula: 3H2 + C4H4N2 = C4H10N2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 49.52 ± 0.67 | kcal/mol | Chyd | Hafelinger and Steinmann, 1977 | liquid phase; solvent: Acetic acid; ALS |
+
= (
•
)
By formula: Li+ + C4H4N2 = (Li+ • C4H4N2)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 35.6 ± 3.3 | kcal/mol | CIDT | Amunugama and Rodgers, 2000 | RCD |
+
= (
•
)
By formula: Na+ + C4H4N2 = (Na+ • C4H4N2)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 25.7 ± 0.8 | kcal/mol | CIDT | Amunugama and Rodgers, 2000 | RCD |
+
= (
•
)
By formula: K+ + C4H4N2 = (K+ • C4H4N2)
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 16.1 ± 0.9 | kcal/mol | CIDT | Amunugama and Rodgers, 2000 | RCD |
References
Go To: Top, Reaction thermochemistry data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Meot-ner and Kafafi, 1988
Meot-ner, M.; Kafafi, S.A.,
Carbon Acidities of Aromatic Compounds,
J. Am. Chem. Soc., 1988, 110, 19, 6297, https://doi.org/10.1021/ja00227a003
. [all data]
Kiefer, Zhang, et al., 1997
Kiefer, J.H.; Zhang, Q.; Kern, R.D.; Yao, J.; Jursic, B.,
Pyrolysis of Aromatic Azines: Pyrazine, Pyrimidine, and Pyridine,
J. Phys. Chem. A, 1997, 101, 38, 7061, https://doi.org/10.1021/jp970211z
. [all data]
Wren, Vogelhuber, et al., 2012
Wren, S.W.; Vogelhuber, K.M.; Garver, J.M.; Kato, S.; Sheps, L.; Bierbaum, V.M.; Lineberger, W.C.,
C-H Bond Strengths and Acidities in Aromatic Systems: Effects of Nitrogen Incorporation in Mono-, Di-, and Triazines,
J. Am. Chem. Soc., 2012, 134, 15, 6584-6595, https://doi.org/10.1021/ja209566q
. [all data]
Hafelinger and Steinmann, 1977
Hafelinger, G.; Steinmann, L.,
Heat of hydrogenation of compounds containing isolated and conjugted C=N bouble bonds,
Angew. Chem. Int. Ed. Engl., 1977, 16, 47-48. [all data]
Amunugama and Rodgers, 2000
Amunugama, R.; Rodgers, M.T.,
Absolute Alkali Metal Ion Binding Affinities of Several Azines Determined by Threshold Collision-Induced Dissociation and Ab Initio Theory,
Int. J. Mass Spectrom., 2000, 195/196, 439, https://doi.org/10.1016/S1387-3806(99)00145-1
. [all data]
Notes
Go To: Top, Reaction thermochemistry 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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