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
  • Phase change data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data
  • IR Spectrum
  • Mass spectrum (electron ionization)
• Data at other public NIST sites:
  • X-ray Photoelectron Spectroscopy Database, version 5.0
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Gas phase thermochemistry 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: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Phase change 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 as indicated in comments:
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Enthalpy of sublimation

Enthalpy of phase transition

Entropy of phase transition

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Phase change data, 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

References

Go To: Top, Gas phase thermochemistry data, Phase change data, 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.

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]

Lähde, Raula, et al., 2009
Lähde, Anna; Raula, Janne; Malm, Jari; Kauppinen, Esko I.; Karppinen, Maarit, Sublimation and vapour pressure estimation of l-leucine using thermogravimetric analysis, Thermochimica Acta, 2009, 482, 1-2, 17-20, https://doi.org/10.1016/j.tca.2008.10.009 . [all data]

Svec and Clyde, 1965
Svec, H.J.; Clyde, D.D., Vapor pressures of some α-amino acids, J. Chem. Eng. Data, 1965, 10, 151. [all data]

Svec and Clyde, 1965, 2
Svec, H.J.; Clyde, D.D., Vapor Pressures of Some α-Amino Acids., J. Chem. Eng. Data, 1965, 10, 2, 151-152, https://doi.org/10.1021/je60025a024 . [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press Inc., London, 1970, 643. [all data]

Clyde and Svec, 1964
Clyde, D.D.; Svec, H., , U. S. Atomic Energy Comm. IS-790, 1964, 1. [all data]

Grunenberg, Bougeard, et al., 1984
Grunenberg, A.; Bougeard, D.; Schrader, B., DSC-investigations of 22 crystalline neutral aliphatic amino acids in the temperature range 233 to 423 K, Thermochim. Acta, 1984, 77, 59-66. [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, Phase change data, Gas phase ion energetics data, References

• Symbols used in this document:
  

  AE	Appearance energy
  ΔHtrs	Enthalpy of phase transition
  ΔStrs	Entropy of phase transition
  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
  ΔsubH	Enthalpy of sublimation

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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