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L-Isoleucine

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Condensed 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 as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Deltafsolid-153.12 ± 0.45kcal/molCcbWu, Zhu, et al., 1993ALS
Deltafsolid-152.5kcal/molCcbHutchens, Cole, et al., 1963ALS
Quantity Value Units Method Reference Comment
Deltacsolid-855.24 ± 0.33kcal/molCcbWu, Zhu, et al., 1993ALS
Deltacsolid-853.72 ± 0.06kcal/molCcbTsuzuki, Harper, et al., 1958Reanalyzed by Cox and Pilcher, 1970, Original value = -855.2 ± 0.2 kcal/mol; ALS
Quantity Value Units Method Reference Comment
solid,1 bar49.711cal/mol*KN/AHutchens, Cole, et al., 1963DH

Constant pressure heat capacity of solid

Cp,solid (cal/mol*K) Temperature (K) Reference Comment
45.000298.15Hutchens, Cole, et al., 1963T = 11 to 310 K.; DH

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

Enthalpy of sublimation

DeltasubH (kcal/mol) Temperature (K) Method Reference
28.7 ± 0.2455.VSvec and Clyde, 1965

Reaction 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: John E. Bartmess

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

C6H12NO2- + Hydrogen cation = L-Isoleucine

By formula: C6H12NO2- + H+ = C6H13NO2

Quantity Value Units Method Reference Comment
Deltar340.1 ± 1.9kcal/molCIDCJones, Bernier, et al., 2007gas phase
Deltar338.7 ± 3.1kcal/molG+TSO'Hair, Bowie, et al., 1992gas phase
Quantity Value Units Method Reference Comment
Deltar331.9 ± 3.0kcal/molCIDCO'Hair, Bowie, et al., 1992gas phase

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

Data compiled as indicated in comments:
B - John E. Bartmess
MM - Michael M. Meot-Ner (Mautner)
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Quantity Value Units Method Reference Comment
Proton affinity (review)219.3kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity211.2kcal/molN/AHunter and Lias, 1998HL

Proton affinity at 298K

Proton affinity (kcal/mol) Reference Comment
220.7Bojesen and Breindahl, 1994PA increased by 1.5 kcal/mol for referencing values to Hunter and Lias, 1998; MM

Ionization energy determinations

IE (eV) Method Reference Comment
8.66PEKlasinc, 1976LLK
9.5 ± 0.2EIJunk and Svec, 1963RDSH

De-protonation reactions

C6H12NO2- + Hydrogen cation = L-Isoleucine

By formula: C6H12NO2- + H+ = C6H13NO2

Quantity Value Units Method Reference Comment
Deltar340.1 ± 1.9kcal/molCIDCJones, Bernier, et al., 2007gas phase; B
Deltar338.7 ± 3.1kcal/molG+TSO'Hair, Bowie, et al., 1992gas phase; B
Quantity Value Units Method Reference Comment
Deltar331.9 ± 3.0kcal/molCIDCO'Hair, Bowie, et al., 1992gas phase; B

IR Spectrum

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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: Coblentz Society, Inc.

Condensed Phase Spectrum

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IR spectrum
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Notice: Except where noted, spectra from this collection were measured on dispersive instruments, often in carefully selected solvents, and hence may differ in detail from measurements on FTIR instruments or in other chemical environments. More information on the manner in which spectra in this collection were collected can be found here.

Notice: Concentration information is not available for this spectrum and, therefore, molar absorptivity values cannot be derived.

Additional Data

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Owner COBLENTZ SOC.
Collection (C) 2018 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.
Source reference COBLENTZ NO. 05105
Date 1961/08/04
Name(s) isoleucine
L-Alpha-AMINO-Beta-METHYLVALERIC ACID
State SOLID (1 mg / 200 mg KBr DISC) VS KBr
Instrument PERKIN-ELMER 21 (GRATING)
Instrument parameters FILTER AT ABOUT 10 MICRONS
Path length 0.055 CM (THICKNESS)
Resolution 2
Sampling procedure TRANSMISSION
Data processing DIGITIZED BY COBLENTZ SOCIETY (BATCH I) FROM HARD COPY
Melting point 284 C DECOMP.

This IR spectrum is from the Coblentz Society's evaluated infrared reference spectra collection.


Mass spectrum (electron ionization)

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

Spectrum

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Mass spectrum
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Additional Data

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Owner NIST Mass Spectrometry Data Center
Collection (C) 2014 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.
Origin Japan AIST/NIMC Database- Spectrum MS-NW- 627
NIST MS number 228158

All mass spectra in this site (plus many more) are available from the NIST/EPA/NIH Mass Spectral Library. Please see the following for information about the library and its accompanying search program.


References

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, IR Spectrum, Mass spectrum (electron ionization), NIST Free Links, 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]

Hutchens, Cole, et al., 1963
Hutchens, J.O.; Cole, A.G.; Stout, J.W., Heat capacities from 11 to 305°K., entropies, and free energies of formation of L-valine, L-isoleucine, and L-leucine, J. Phys. Chem., 1963, 67, 1128-1130. [all data]

Tsuzuki, Harper, et al., 1958
Tsuzuki, T.; Harper, D.O.; Hunt, H., Heats of combustion. VII. The heats of combustion of some amino acids, J. Phys. Chem., 1958, 62, 1594-1595. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

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

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]

Bojesen and Breindahl, 1994
Bojesen, G.; Breindahl, T., On the Proton Affinity od Some Alpha-Amino Acids and the Theory of the Kinetic Method., J. Chem. Soc. Perkin 2, 1994, 1029. [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 «alpha»-amino acids, J. Am. Chem. Soc., 1963, 85, 839. [all data]


Notes

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, IR Spectrum, Mass spectrum (electron ionization), NIST Free Links, References