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

NOTICE: Due to scheduled maintenance at our Gaithersburg campus, this site will not be available from 5:00 pm EDT (21:00 UTC) on Friday October 25 until 5:00 pm (21:00 UTC) on Sunday October 27. We apologize for any inconvenience this outage may cause.

Pyridine

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
MM - Michael M. Meot-Ner (Mautner)
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
IE (evaluated)9.26 ± 0.01eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)930.kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity898.1kJ/molN/AHunter and Lias, 1998HL

Proton affinity at 298K

Proton affinity (kJ/mol) Reference Comment
936.5 ± 8.5Wind, Papp, et al., 2005T = 298K; MM

Protonation entropy at 298K

Protonation entropy (J/mol*K) Reference Comment
-1. ± 10.Wind, Papp, et al., 2005T = 298K; MM

Ionization energy determinations

IE (eV) Method Reference Comment
9.34 ± 0.03EIArimura and Yoshikawa, 1984LBLHLM
9.25TRPILifshitz, 1982LBLHLM
9.60PEKimura, Katsumata, et al., 1981LLK
9.26PEUtsunomiya, Kobayashi, et al., 1978LLK
9.25PIEland, Berkowitz, et al., 1978LLK
9.74 ± 0.05EIZaretskii, Oren, et al., 1976LLK
~9.5EIVan Veen and Plantenga, 1975LLK
9.9 ± 0.1EIStefanovic and Grutzmacher, 1974LLK
9.263PEKing, Murrell, et al., 1972LLK
9.66 ± 0.03EIJohnstone and Mellon, 1972LLK
9.70 ± 0.05EIDistefano, Foffani, et al., 1971LLK
9.70EIDistefano, Foffani, et al., 1971, 2LLK
9.30 ± 0.01PIPotapov and Sorokin, 1970RDSH
9.10PEGoffart, Momigny, et al., 1969RDSH
9.10 ± 0.01PIGoffart, Momigny, et al., 1969RDSH
9.31PEDewar and Worley, 1969RDSH
9.28PEAl-Joboury and Turner, 1964RDSH
9.20 ± 0.05PIAkopyan and Vilesov, 1964RDSH
9.4PITerenin, 1961RDSH
9.266SEl-Sayed, Kaaba, et al., 1961RDSH
9.23 ± 0.03PIWatanabe, 1957RDSH
9.8 ± 0.2EIHustrulid, Kusch, et al., 1938RDSH
9.51PEKlasinc, Novak, et al., 1978Vertical value; LLK
9.66PEKobayashi and Nagakura, 1974Vertical value; LLK
9.7PEBatich, Heilbronner, et al., 1973Vertical value; LLK
9.6 ± 0.5PEHeilbronner, Hornung, et al., 1972Vertical value; LLK
9.59PEGleiter, Heilbronner, et al., 1970Vertical value; RDSH

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
C3H3+14.00 ± 0.10?EIMomigny, Urbain, et al., 1965RDSH
C3H3N+13.84 ± 0.10C2H2EIMomigny, Urbain, et al., 1965RDSH
C4H2+16.17 ± 0.10HCN+H2EIMomigny, Urbain, et al., 1965RDSH
C4H3+16.61 ± 0.10HCN+HEIMomigny, Urbain, et al., 1965RDSH
C4H4+11.84 ± 0.05HCNTRPILifshitz and Malinovich, 1984LBLHLM
C4H4+12.6 ± 0.1HCNEIBurgers and Holmes, 1984LBLHLM
C4H4+12.34 ± 0.05HCNEIBurgers and Holmes, 1984LBLHLM
C4H4+12.0 ± 0.2HCNTRPILifshitz, 1982LBLHLM
C4H4+12.15 ± 0.02HCNPIPECORosenstock, Stockbauer, et al., 1981LLK
C4H4+11.8HCNPIEland, Berkowitz, et al., 1978LLK
C4H4+12.3 ± 0.1HCNEIRosenstock, McCulloh, et al., 1977LLK
C4H4+13.41 ± 0.05HCNEIZaretskii, Oren, et al., 1976LLK
C4H4+13.28HCNEIBeynon, Hopkinson, et al., 1969RDSH
C5H3N+12.42 ± 0.10H2EIMomigny, Urbain, et al., 1965RDSH
C5H4N+14.00 ± 0.10HEIMomigny, Urbain, et al., 1965RDSH

De-protonation reactions

C5H4N- + Hydrogen cation = Pyridine

By formula: C5H4N- + H+ = C5H5N

Quantity Value Units Method Reference Comment
Deltar1631. ± 8.4kJ/molIMRESchafman and Wenthold, 2007gas phase; B
Deltar1636. ± 10.kJ/molTDEqMeot-ner and Kafafi, 1988gas 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
Deltar1601. ± 8.4kJ/molTDEqMeot-ner and Kafafi, 1988gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B
Deltar1607. ± 13.kJ/molIMRBDePuy, Kass, et al., 1988gas phase; Comparable to water in acidity; B
Deltar<1574. ± 8.4kJ/molIMRBBruins, Ferrer-Correia, et al., 1978gas phase; O- deprotonates; 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]

Wind, Papp, et al., 2005
Wind, J.J.; Papp, L.; Happel, M.; Hahn, K.; Andriole, E.J.; Poutsma, J.C., Proton Affinity of beta-Oxalylaminoalanine (BOAA): Incorporation of Direct Entropy Correction into the Single-Reference Kinetic Method, J. Am. Soc. Mass Spectrom., 2005, 16, 1151. [all data]

Arimura and Yoshikawa, 1984
Arimura, M.; Yoshikawa, Y., Ionization efficiency and ionization energy of cyclic compounds by electron impact, Mass Spectrosc. (Tokyo), 1984, 32, 375. [all data]

Lifshitz, 1982
Lifshitz, C., Time-dependent mass spectra and breakdown graphs. 2. The kinetic shift in pyridine, J. Phys. Chem., 1982, 86, 606. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Utsunomiya, Kobayashi, et al., 1978
Utsunomiya, C.; Kobayashi, T.; Nagakura, S., Photoelectron angular distribution measurements for some pyridines, Bull. Chem. Soc. Jpn., 1978, 451, 3482. [all data]

Eland, Berkowitz, et al., 1978
Eland, J.H.D.; Berkowitz, J.; Schulte, H.; Frey, R., Rates of unimolecular pyridine ion decay and the heat of formation of C4H4+, Int. J. Mass Spectrom. Ion Phys., 1978, 28, 297. [all data]

Zaretskii, Oren, et al., 1976
Zaretskii, Z.V.I.; Oren, D.; Kelner, L., Automatic method for the measurement of the electron impact ionization and appearance potentials, Appl. Spectrosc., 1976, 30, 366. [all data]

Van Veen and Plantenga, 1975
Van Veen, E.H.; Plantenga, F.L., Threshold electron-impact excitation spectrum of pyridine, Chem. Phys. Lett., 1975, 30, 28. [all data]

Stefanovic and Grutzmacher, 1974
Stefanovic, D.; Grutzmacher, H.F., The ionisation potential of some substituted pyridines, Org. Mass Spectrom., 1974, 9, 1052. [all data]

King, Murrell, et al., 1972
King, G.H.; Murrell, J.N.; Suffolk, R.J., The vacuum-ultraviolet photoelectron spectra of fluoropyridines, J. Chem. Soc. Dalton Trans., 1972, 564. [all data]

Johnstone and Mellon, 1972
Johnstone, R.A.W.; Mellon, F.A., Electron-impact ionization and appearance potentials, J. Chem. Soc. Faraday Trans. 2, 1972, 68, 1209. [all data]

Distefano, Foffani, et al., 1971
Distefano, G.; Foffani, A.; Innorta, G.; Pignataro, S., Mass spectrometric study of transition metal complexes with ligands having nitrogen or sulphur as donor atom, Adv. Mass Spectrom., 1971, 5, 696. [all data]

Distefano, Foffani, et al., 1971, 2
Distefano, G.; Foffani, A.; Innorta, G.; Pignataro, S., Electron impact ionization potentials of some manganese, chromium and tungsten organometallic derivatives, Int. J. Mass Spectrom. Ion Phys., 1971, 7, 383. [all data]

Potapov and Sorokin, 1970
Potapov, V.K.; Sorokin, V.V., Investigation of ionic molecular reactions proceeding during photoionization of aromatic compounds and alcohols, Dokl. Akad. Nauk SSSR, 1970, 195, 616, In original 848. [all data]

Goffart, Momigny, et al., 1969
Goffart, C.; Momigny, J.; Natalis, P., Photoionization studies by total ionization measurements and photoelectron spectra. II.Pyridine, Intern. J. Mass Spectrom. lon Phys., 1969, 3, 371. [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]

Al-Joboury and Turner, 1964
Al-Joboury, M.I.; Turner, D.W., Molecular photoelectron spectroscopy. Part II. A summary of ionization potentials, J. Chem. Soc., 1964, 4434. [all data]

Akopyan and Vilesov, 1964
Akopyan, M.E.; Vilesov, F.I., Excited states of positive ions and dissociative photoionization of aromatic amines, Dokl. Akad. Nauk SSSR, 1964, 158, 1386, In original 965. [all data]

Terenin, 1961
Terenin, A., Charge transfer in organic solids, induced by light, Proc. Chem. Soc., London, 1961, 321. [all data]

El-Sayed, Kaaba, et al., 1961
El-Sayed, M.F.A.; Kaaba, M.; Tanaka, Y., Ionization potentials of benzene, hexadeuterobenzene, and pyridine from their observed Rydberg series in the region 600-2000 A, J. Chem. Phys., 1961, 34, 334. [all data]

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Hustrulid, Kusch, et al., 1938
Hustrulid, A.; Kusch, P.; Tate, J.T., The dissociation of benzene (C6H6), pyridine (C5H5N) and cyclohexane (C6H12) by electron impact, Phys. Rev., 1938, 54, 1037. [all data]

Klasinc, Novak, et al., 1978
Klasinc, L.; Novak, I.; Scholz, M.; Kluge, G., Photoelektronenspektren substituierter Pyridine und Benzole und ihre Interpretation durch die CNDO/SWW-Methode, Croat. Chem. Acta, 1978, 51, 43. [all data]

Kobayashi and Nagakura, 1974
Kobayashi, T.; Nagakura, S., Photoelectron spectra of aminopyridines and cyanopyridines, J. Electron Spectrosc. Relat. Phenom., 1974, 4, 207. [all data]

Batich, Heilbronner, et al., 1973
Batich, C.; Heilbronner, E.; Hornung, V.; Ashe, A.J.; Clark, D.T.; Cobley, U.T.; Kilcast, D.; Scanlan, I., Photoelectron spectra of phosphabenzen, arsabenzene, and stibabenzene, J. Am. Chem. Soc., 1973, 95, 928. [all data]

Heilbronner, Hornung, et al., 1972
Heilbronner, E.; Hornung, V.; Pinkerton, F.H.; Thames, S.F., 31. Photoelectron spectra of azabenzenes and azanaphthalenes: III. The orbital sequence in methyl- and trimethylsilyl- substituted pyridines, Helv. Chim. Acta, 1972, 55, 289. [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]

Lifshitz and Malinovich, 1984
Lifshitz, C.; Malinovich, Y., Time resolved photoionization mass spectrometry in the millisecond range, Int. J. Mass Spectrom. Ion Processes, 1984, 60, 99. [all data]

Burgers and Holmes, 1984
Burgers, P.C.; Holmes, J.L., Fragmentation rate constants and appearance energies for reactions having a large kinetic shift and the energy partitioning in their metastable decomposition, Int. J. Mass Spectrom. Ion Processes, 1984, 58, 15. [all data]

Rosenstock, Stockbauer, et al., 1981
Rosenstock, H.M.; Stockbauer, R.; Parr, A.C., Unimolecular kinetis of pyridine ion fragmentation, Int. J. Mass Spectrom. Ion Phys., 1981, 38, 323. [all data]

Rosenstock, McCulloh, et al., 1977
Rosenstock, H.M.; McCulloh, K.E.; Lossing, F.P., On the mechanisms of C6H6 ionization fragmentation, Int. J. Mass Spectrom. Ion Phys., 1977, 25, 327. [all data]

Beynon, Hopkinson, et al., 1969
Beynon, J.H.; Hopkinson, J.A.; Lester, G.R., Mass spectrometry-the appearance potentials of "meta-stable peaks" in some aromatic nitro compounds - a chemical reaction in the mass spectrometer, Intern. J. Mass Spectrom. Ion Phys., 1969, 2, 291. [all data]

Schafman and Wenthold, 2007
Schafman, B.S.; Wenthold, P.G., Regioselectivity of pyridine deprotonation in the gas phase, J. Org. Chem., 2007, 72, 5, 1645-1651, https://doi.org/10.1021/jo062117x . [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]

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]

DePuy, Kass, et al., 1988
DePuy, C.H.; Kass, S.R.; Bean, G.P., Formation and Reactions of Heteroaromatic Anions in the Gas Phase, J. Org. Chem., 1988, 53, 19, 4427, https://doi.org/10.1021/jo00254a001 . [all data]

Bruins, Ferrer-Correia, et al., 1978
Bruins, A.P.; Ferrer-Correia, A.J.; Harrison, A.G.; Jennings, K.R.; Mithcum, R.K., Negative ion chemical ionization mass spectrometry of some aromatic compounds using O-. as the reagent ion, Adv. Mass Spectrom., 1978, 7, 355. [all data]


Notes

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