L-Cysteine anion
- Formula: C3H6NO2S-
- Molecular weight: 120.151
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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 compiled by: John E. Bartmess
Electron affinity of neutral species
| EAneutral (eV) | Method | Reference | Comment |
|---|---|---|---|
| 4.00 ± 0.16 | D-EA | Tian, Pawlow, et al., 2007 | Calcn say SH is 3.1 kcal/mol more acidic than CO2H. See DeBlase, Kass, et al., 2014 for spectroscopy saying that it is a cyclic H-bonded species |
Protonation reactions
C3H6NO2S- + =
By formula: C3H6NO2S- + H+ = C3H7NO2S
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 333.4 ± 2.2 | kcal/mol | CIDC | Jones, Bernier, et al., 2007 | gas phase |
| ΔrH° | 334.3 ± 2.3 | kcal/mol | G+TS | Tian, Pawlow, et al., 2007 | gas phase; Calcn say SH is 3.1 kcal/mol more acidic than CO2H. See DeBlase, Kass, et al., 2014 for spectroscopy saying that it is a cyclic H-bonded species |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 327.5 ± 2.1 | kcal/mol | N/A | Tian, Pawlow, et al., 2007 | gas phase; Calcn say SH is 3.1 kcal/mol more acidic than CO2H. See DeBlase, Kass, et al., 2014 for spectroscopy saying that it is a cyclic H-bonded species |
| ΔrG° | 326.0 ± 3.0 | kcal/mol | CIDC | O'Hair, Bowie, et al., 1992 | gas phase |
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.
Tian, Pawlow, et al., 2007
Tian, Z.X.; Pawlow, A.; Poutsma, J.C.; Kass, S.R.,
Are carboxyl groups the most acidic sites in amino acids? Gas-phase acidity, H/D exchange experiments, and computations on cysteine and its conjugate base,
J. Am. Chem. Soc., 2007, 129, 17, 5403-5407, https://doi.org/10.1021/ja0666194
. [all data]
DeBlase, Kass, et al., 2014
DeBlase, A.F.; Kass, S.R.; Johnson, M.A.,
On the character of the cyclic ionic H-bond in cryogenically cooled deprotonated cysteine,
Phys. Chem. Chem. Phys., 2014, 16, 10, 4569-4575, https://doi.org/10.1039/c3cp54117g
. [all data]
Jones, Bernier, et al., 2007
Jones, C.M.; Bernier, M.; Carson, E.; Colyer, K.E.; Metz, R.; Pawlow, A.; Wischow, E.D.; Webb, I.; Andriole, E.J.; Poutsma, J.C.,
Gas-phase Acities of the 20 Protein Amino Acids,
Int. J. Mass Spectrom., 2007, 267, 1-3, 54-62, https://doi.org/10.1016/j.ijms.2007.02.018
. [all data]
O'Hair, Bowie, et al., 1992
O'Hair, R.J.; Bowie, J.H.; Gronert, S.,
Gas Phase Acidity of the alpha-Amino Acids,
Int. J. Mass Spectrom. Ion Proc., 1992, 117, 23, https://doi.org/10.1016/0168-1176(92)80083-D
. [all data]
Notes
Go To: Top, Gas phase ion energetics data, References
- Symbols used in this document:
EAneutral Electron affinity of neutral species 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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