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1H-Pyrazole

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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 evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias

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

Quantity Value Units Method Reference Comment
Proton affinity (review)894.1kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity860.5kJ/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
9.38 ± 0.03PELichtenberger, Copenhaver, et al., 1988LL
9.25 ± 0.01PIMain-Bobo, Loesik, et al., 1986LBLHLM
9.27 ± 0.05PEBaker, Betteridge, et al., 1970RDSH
9.15PEDaamen, Oskam, et al., 1979Vertical value; LLK
9.15PECradock, Findlay, et al., 1973Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CH2N+11.72 ± 0.05C2H2NPIMain-Bobo, Loesik, et al., 1986LBLHLM
C2H3N+11.76 ± 0.02CHNPIMain-Bobo, Loesik, et al., 1986LBLHLM

De-protonation reactions

C3H3N2- + Hydrogen cation = 1H-Pyrazole

By formula: C3H3N2- + H+ = C3H4N2

Quantity Value Units Method Reference Comment
Deltar1479. ± 10.kJ/molG+TSGianola, Ichino, et al., 2006gas phase; B
Deltar1479. ± 10.kJ/molG+TSTaft, Anvia, et al., 1986gas phase; value altered from reference due to change in acidity scale; B
Quantity Value Units Method Reference Comment
Deltar1449. ± 9.6kJ/molN/AGianola, Ichino, et al., 2006gas phase; B
Deltar1449. ± 9.6kJ/molIMRETaft, Anvia, et al., 1986gas phase; value altered from reference due to change in 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]

Lichtenberger, Copenhaver, et al., 1988
Lichtenberger, D.L.; Copenhaver, A.S.; Gray, H.B.; Marshall, J.L.; Hopkins, M.D., Valence electronic structure of bis(Pyrazolyl)-bridged iridium dicarbonyl dimers. Electronic effects of 3,5-dimethylpyraxzolyl substitution on metal-metal interactions, Inorg. Chem., 1988, 27, 4488. [all data]

Main-Bobo, Loesik, et al., 1986
Main-Bobo, J.; Loesik, S.; Gase, W.; Baer, T.; Mommers, A.; Holmes, J., The thermochemistry and dissociation dynamics of internal-energy selected pyrazole and imidazole ions, J. Am. Chem. Soc., 1986, 108, 677. [all data]

Baker, Betteridge, et al., 1970
Baker, A.D.; Betteridge, D.; Kemp, N.R.; Kirby, R.E., Application of photoelectron spectrometry to pesticide analysis. Photoelectron spectra of fivemembered heterocycles and related molecules, Anal. Chem., 1970, 42, 1064. [all data]

Daamen, Oskam, et al., 1979
Daamen, H.; Oskam, A.; Stufkens, D.J.; Waaijers, H.W., Bonding properties of group VIB metal pentacarbonyl azole complexes studied by electronic absorption, photoelectron, 13C NMR and vibrational spectroscopy, Inorg. Chim. Acta, 1979, 34, 253. [all data]

Cradock, Findlay, et al., 1973
Cradock, S.; Findlay, R.H.; Palmer, M.H., The molecular energy levels of the azoles: A study by photoelectron spectroscopy and ab initio molecular orbital calculations, Tetrahedron, 1973, 29, 2173. [all data]

Gianola, Ichino, et al., 2006
Gianola, A.J.; Ichino, T.; Kato, S.; Bierbaum, V.M.; Lineberger, W.C., Thermochemical studies of pyrazolide, J. Phys. Chem. A, 2006, 110, 27, 8457-8466, https://doi.org/10.1021/jp057499+ . [all data]

Taft, Anvia, et al., 1986
Taft, R.W.; Anvia, F.; Taagepera, M.; Catalan, J.; Elgueroy, J., Electrostatic proximity effects in the relative basicities of pyrazole, imidazole, pyridazine, and pyrimidine, J. Am. Chem. Soc., 1986, 108, 3237. [all data]


Notes

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