Leucine

• Formula: C₆H₁₃NO₂
• Molecular weight: 131.1729
• IUPAC Standard InChI: InChI=1S/C6H13NO2/c1-4(2)3-5(7)6(8)9/h4-5H,3,7H2,1-2H3,(H,8,9)/t5-/m1/s1 Copy

  
• IUPAC Standard InChIKey: ROHFNLRQFUQHCH-RXMQYKEDSA-N Copy
• CAS Registry Number: 61-90-5
• Chemical structure:
  This structure is also available as a 2d Mol file
• Stereoisomers:
  • Leucine
  • D-Leucine
  • DL-Leucine
• Other names: L-Leucine; Leucine, L-; L-α-Aminoisocaproic acid; α-Amino-γ-methylvaleric acid; (S)-(+)-Leucine; L-(+)-Leucine; Leu; Pentanoic acid, 2-amino-4-methyl-, (S)-; 2-Amino-4-methylpentanoic acid, (L)-; 2-Amino-4-methylvaleric acid, (L)-; iso-C4H9CH(NH2)COOH; L-(-)-2-Amino-4-methylpentanoic acid; Norvaline, 4-methyl-, (L)-; Valeric acid, 2-amino-4-methyl-, (S)-; Leucin; (S)-2-Amino-4-methylpentanoic acid; (S)-Leucine; (S)-2-Amino-4-methylvaleric acid; L-Norvaline, 4-methyl-; NSC 46709
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Gas phase ion energetics data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • IR Spectrum
• Data at other public NIST sites:
  • X-ray Photoelectron Spectroscopy Database, version 5.0
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Gas phase thermochemistry data

Go To: Top, Gas phase ion energetics data, Mass spectrum (electron ionization), References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Mass spectrum (electron ionization), 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

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₆H₁₂NO₂^- +  =

By formula: C₆H₁₂NO₂^- + H⁺ = C₆H₁₃NO₂

Mass spectrum (electron ionization)

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

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

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Additional Data

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Wu, Zhu, et al., 1993
Wu, D.; Zhu, Y.; Gao, Z.; Qu, S., Determination of combustion heat of some amino acids, Wuhan Daxue Xuebao Ziran Kexueban, 1993, 78-82. [all data]

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]

Klasinc, 1976
Klasinc, L., Application of photoelectron spectroscopy to biologically active molecules and their constituent parts, J. Electron Spectrosc. Relat. Phenom., 1976, 8, 161. [all data]

Junk and Svec, 1963
Junk, G.; Svec, H., The mass spectra of the α-amino acids, J. Am. Chem. Soc., 1963, 85, 839. [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 thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), References

• Symbols used in this document:
  

  AE	Appearance energy
  ΔcH°gas	Enthalpy of combustion of gas at standard conditions
  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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