Indole

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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
L - 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

View reactions leading to C8H7N+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)7.7602 ± 0.0006eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)223.1kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity215.6kcal/molN/AHunter and Lias, 1998HL

Electron affinity determinations

EA (eV) Reference Comment
0.00351 ± 0.00022Carles, Desfrancois, et al., 2000Dipole bound state; B

Ionization energy determinations

IE (eV) Method Reference Comment
7.7602 ± 0.0006LSHager and Wallace, 1988LL
7.7610 ± 0.0006PEHager, Ivanco, et al., 1985LBLHLM
7.90EICorval, 1979LLK
8.29 ± 0.05EIThorstad and Undheim, 1974LLK
7.78PEDewar, Harget, et al., 1970RDSH
7.75 ± 0.05PEEland, 1969RDSH
7.91PEKovac, Klasinc, et al., 1980Vertical value; LLK
7.92 ± 0.05PEDomelsmith, Munchausen, et al., 1977Vertical value; LLK
7.75 ± 0.015PEGusten, Klasinc, et al., 1976Vertical value; LLK
7.87PEDolby, Hanson, et al., 1976Vertical value; LLK

De-protonation reactions

C8H6N- + Hydrogen cation = Indole

By formula: C8H6N- + H+ = C8H7N

Quantity Value Units Method Reference Comment
Δr351.9 ± 2.5kcal/molTDEqMeot-ner, Liebman, et al., 1988gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B
Δr349.2 ± 2.1kcal/molG+TSTaft and Bordwell, 1988gas phase; B
Quantity Value Units Method Reference Comment
Δr344.1 ± 2.0kcal/molTDEqMeot-ner, Liebman, et al., 1988gas phase; anchored to 88MEO scale, not the "87 acidity scale". The Kiefer, Zhang, et al., 1997 BDE is for ortho.; B
Δr341.9 ± 2.0kcal/molIMRETaft and Bordwell, 1988gas phase; 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]

Carles, Desfrancois, et al., 2000
Carles, S.; Desfrancois, C.; Schermann, J.P.; Smith, D.M.A.; Adamowicz, L., Structures and electron affinities of indole-(water)(N) clusters, J. Chem. Phys., 2000, 112, 8, 3726-3734, https://doi.org/10.1063/1.480938 . [all data]

Hager and Wallace, 1988
Hager, J.W.; Wallace, S.C., Two-laser photoionization supersonic jet mass spectrometry of aromatic molecules, Anal. Chem., 1988, 60, 5. [all data]

Hager, Ivanco, et al., 1985
Hager, J.; Ivanco, M.; Smith, M.A.; Wallace, S.C., Solvation effects in jet-cooled Van der Waals Clusters: Two-color threshold photoionization spectroscopy of indole, indole-argon, indole-methane, indole-water and indole-methanol, Chem. Phys. Lett., 1985, 113, 503. [all data]

Corval, 1979
Corval, M., Elimination sous impact electronique de HCN et H a partir de l'Indole. Comparaison avec l'Indolizine, Org. Mass Spectrom., 1979, 14, 213. [all data]

Thorstad and Undheim, 1974
Thorstad, O.; Undheim, K., Mass spectrometry of onium compounds. XXIV. Ionisation potential in structure analysis of pyridodiazo-oxides, Chem. Scr., 1974, 6, 222. [all data]

Dewar, Harget, et al., 1970
Dewar, M.J.S.; Harget, A.J.; Trinajstic, N.; Worley, S.D., Ground states of conjugated molecules-XXI.Benzofurans and benzopyrroles, Tetrahedron, 1970, 26, 4505. [all data]

Eland, 1969
Eland, J.H.D., Photoelectron spectra of conjugated hydrocarbons and heteromolecules, Intern. J. Mass Spectrom. Ion Phys., 1969, 2, 471. [all data]

Kovac, Klasinc, et al., 1980
Kovac, B.; Klasinc, L.; Stanovnik, B.; Tisler, M., Photoelectron spectroscopy of J. Heterocycl. Chem.. Azaindenes azaindolizines (1), J. Heterocycl. Chem., 1980, 17, 689. [all data]

Domelsmith, Munchausen, et al., 1977
Domelsmith, L.N.; Munchausen, L.L.; Houk, K.N., Photoelectron spectra of psychotropic drugs. 1. Phenethylamines, tryptamines, and LSD, J. Am. Chem. Soc., 1977, 99, 4311. [all data]

Gusten, Klasinc, et al., 1976
Gusten, H.; Klasinc, L.; Ruscic, B., Photoelectron spectroscopy of J. Heterocycl. Chem.. Indene analogs, Z. Naturforsch. A:, 1976, 31, 1051. [all data]

Dolby, Hanson, et al., 1976
Dolby, L.J.; Hanson, G.; Koenig, T., The He I photoelectron spectra of N-methylisoindole and N-methylindole, J. Org. Chem., 1976, 41, 3537. [all data]

Meot-ner, Liebman, et al., 1988
Meot-ner, M.; Liebman, J.F.; Kafafi, S.A., Ionic Probes of Aromaticity in Annelated Rings, J. Am. Chem. Soc., 1988, 110, 18, 5937, https://doi.org/10.1021/ja00226a001 . [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]

Taft and Bordwell, 1988
Taft, R.W.; Bordwell, F.G., Structural and Solvent Effects Evaluated from Acidities Measured in Dimethyl Sulfoxide and in the Gas Phase, Acc. Chem. Res., 1988, 21, 12, 463, https://doi.org/10.1021/ar00156a005 . [all data]


Notes

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