Home Symbol which looks like a small house Up Solid circle with an upward pointer in it

Pyridazine

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.


Gas phase ion energetics 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 evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C4H4N2+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)8.74 ± 0.11eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)907.2kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity877.1kJ/molN/AHunter and Lias, 1998HL

Electron affinity determinations

EA (eV) Method Reference Comment
0.01201EFDSuess, Liu, et al., 2003B
>-0.31699ETSNenner and Schultz, 1975Pyridazine. EA estimated as 0.25 eV based on solution phase electrochemical correlations; B

Ionization energy determinations

IE (eV) Method Reference Comment
8.64PEGleiter, Heilbronner, et al., 1972LLK
8.706 ± 0.001PEAsbrink, Fridh, et al., 1972LLK
8.90PEDewar and Worley, 1969RDSH
8.71 ± 0.01PIYencha and El-Sayed, 1968RDSH
9.31PESuffolk, 1974Vertical value; LLK
9.31PEGleiter, Heilbronner, et al., 1970Vertical value; RDSH

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
C2H2+14.94 ± 0.10?EIMomigny, Urbain, et al., 1965RDSH
C2H2+15.79 ± 0.05?EIMomigny, Urbain, et al., 1965RDSH
C2H2+15.23 ± 0.10?EIMomigny, Urbain, et al., 1965RDSH
C4H2+13.67 ± 0.10N2+H2EIMomigny, Urbain, et al., 1965RDSH
C4H3+13.84 ± 0.10N2+HEIMomigny, Urbain, et al., 1965RDSH
C4H4+11.64 ± 0.05N2EIMomigny, Urbain, et al., 1965RDSH

De-protonation reactions

C4H3N2- + Hydrogen cation = Pyridazine

By formula: C4H3N2- + H+ = C4H4N2

Quantity Value Units Method Reference Comment
Deltar1600. ± 10.kJ/molTDEqMeot-ner and Kafafi, 1988gas phase; Pyridazine. Anchored to 88MEO scale, not the "87 Acidity Scale".; B
Quantity Value Units Method Reference Comment
Deltar1564.8 ± 2.9kJ/molN/AWren, Vogelhuber, et al., 2012gas phase; B
Deltar1562. ± 8.4kJ/molTDEqMeot-ner and Kafafi, 1988gas phase; Pyridazine. Anchored to 88MEO scale, not the "87 Acidity Scale".; 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.

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Suess, Liu, et al., 2003
Suess, L.; Liu, Y.; Parthasarathy, R.; Dunning, F.B., Dipole-bound negative ions: Collisional destruction and blackbody-radiation-induced photodetachment, J. Chem. Phys., 2003, 119, 24, 12890-12894, https://doi.org/10.1063/1.1628215 . [all data]

Nenner and Schultz, 1975
Nenner, I.; Schultz, G.J., Temporary negative ions and electron affinities of benzene and N-heterocyclic molecules: Pyridine, pyridazine, pyrimidine, pyrazine, and s-triazine, J. Chem. Phys., 1975, 62, 1747. [all data]

Gleiter, Heilbronner, et al., 1972
Gleiter, R.; Heilbronner, E.; Hornung, V., Photoelectron spectra of azabenzenes azanaphthalenes: I. Pyridine, diazines s-triazine and s-tetrazine, Helv. Chim. Acta, 1972, 55, 255. [all data]

Asbrink, Fridh, et al., 1972
Asbrink, L.; Fridh, C.; Jonsson, B.O.; Lindholm, E., Rydberg series in small molecules. XVII. Photoelectron, UV, mass and electron impact spectra of pyridazine, Int. J. Mass Spectrom. Ion Phys., 1972, 8, 229. [all data]

Dewar and Worley, 1969
Dewar, M.J.S.; Worley, S.D., Photoelectron spectra of molecules. II.The ionization potentials of azabenzenes and azanaphthalenes, J. Chem. Phys., 1969, 51, 263. [all data]

Yencha and El-Sayed, 1968
Yencha, A.J.; El-Sayed, M.A., Lowest ionization potentials of some nitrogen heterocyclics, J. Chem. Phys., 1968, 48, 3469. [all data]

Suffolk, 1974
Suffolk, R.J., The photoelectron spectra of the perfluorodiazines, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 53. [all data]

Gleiter, Heilbronner, et al., 1970
Gleiter, R.; Heilbronner, E.; Hornung, V., Lone pair interaction in pyridazine, pyrimidine, and pyrazine, Angew. Chem. Int. Ed. Engl., 1970, 9, 901. [all data]

Momigny, Urbain, et al., 1965
Momigny, J.; Urbain, J.; Wankenne, H., Les effets de l'impact electronique sur la pyridine et les diazines isomeres, Bull. Soc. Roy. Sci. Liege, 1965, 34, 337. [all data]

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]

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]


Notes

Go To: Top, Gas phase ion energetics data, References