Pyridine, 4-methyl-
- Formula: C6H7N
- Molecular weight: 93.1265
- IUPAC Standard InChIKey: FKNQCJSGGFJEIZ-UHFFFAOYSA-N
- CAS Registry Number: 108-89-4
- 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: 4-Picoline; γ-Methylpyridine; γ-Picoline; p-Methylpyridine; p-Picoline; Ba 35846; 4-Methylpyridine; para-Methylpyridine; gamma-Picoline; NSC 18252
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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
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 C6H7N+ (ion structure unspecified)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Proton affinity (review) | 226.4 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 218.8 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
9.46 ± 0.05 | EI | Zaretskii, Oren, et al., 1976 | LLK |
9.5 ± 0.1 | EI | Stefanovic and Grutzmacher, 1974 | LLK |
9.55 ± 0.05 | EI | Distefano, Foffani, et al., 1971 | LLK |
9.55 | EI | Distefano, Foffani, et al., 1971, 2 | LLK |
9.04 ± 0.03 | PI | Watanabe, Nakayama, et al., 1962 | RDSH |
9.41 | PE | Klasinc, Novak, et al., 1978 | Vertical value; LLK |
9.50 ± 0.05 | PE | Heilbronner, Hornung, et al., 1972 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
C5H6+ | 12.86 ± 0.05 | HCN | EI | Zaretskii, Oren, et al., 1976 | LLK |
C6H6N+ | 12.2 ± 0.1 | H | EI | Palmer and Lossing, 1963 | RDSH |
De-protonation reactions
C6H6N- + =
By formula: C6H6N- + H+ = C6H7N
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 369.7 ± 5.1 | kcal/mol | G+TS | 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 |
ΔrH° | 374.8 ± 3.1 | kcal/mol | G+TS | DePuy, Kass, et al., 1988 | gas phase; Acid: p-methylpyridine. Between iPrOH, MeCN.; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 362.9 ± 5.0 | kcal/mol | IMRB | 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 |
ΔrG° | 368.0 ± 3.0 | kcal/mol | IMRB | DePuy, Kass, et al., 1988 | gas phase; Acid: p-methylpyridine. Between iPrOH, MeCN.; 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]
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]
Stefanovic and Grutzmacher, 1974
Stefanovic, D.; Grutzmacher, H.F.,
The ionisation potential of some substituted pyridines,
Org. Mass Spectrom., 1974, 9, 1052. [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]
Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J.,
Ionization potentials of some molecules,
J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [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]
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]
Palmer and Lossing, 1963
Palmer, T.F.; Lossing, F.P.,
Free radicals by mass spectrometry. XXX. Ionization potentials of anilino and 2-, 3-, and 4-pyridylmethyl radicals,
J. Am. Chem. Soc., 1963, 85, 1733. [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]
Notes
Go To: Top, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy 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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