Conformational composition of neutral leucine. Matrix isolation infrared and ab initio study

Stepan G. Stepanian, Alexander Yu Ivanov, Ludwik Adamowicz

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Low-temperature matrix-isolation FTIR spectroscopy and ab initio calculations are employed to determine conformational composition of neutral leucine. The presence of three leucine conformers in the matrices is revealed. This is in agreement with the results of a detailed study of the potential energy surface of leucine which demonstrates that only five out of 105 possible conformers should have populations in the matrices larger than 2% and only three conformers, which are the ones detected in the experiment, should have populations larger than 10%. UV irradiation of the matrix samples are used to separate bands of the different conformers. We also show that the populations of the leucine conformers in the gas phase at 440 K are significantly different from the ones in matrices. The population of the lowest energy con- former in the gas phase being approximately 23% in the gas phase increases to over 64% in matrices.

Original languageEnglish (US)
Pages (from-to)20-29
Number of pages10
JournalChemical Physics
Volume423
DOIs
StatePublished - 2013

Fingerprint

leucine
Leucine
isolation
Infrared radiation
matrices
Chemical analysis
Gases
vapor phases
Potential energy surfaces
potential energy
Irradiation
Spectroscopy
irradiation
spectroscopy
Experiments

Keywords

  • Ab initio calculations
  • Conformer interconversion
  • Gibbs free energies
  • IR spectroscopy
  • Leucine
  • Matrix isolation

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Physics and Astronomy(all)

Cite this

Conformational composition of neutral leucine. Matrix isolation infrared and ab initio study. / Stepanian, Stepan G.; Ivanov, Alexander Yu; Adamowicz, Ludwik.

In: Chemical Physics, Vol. 423, 2013, p. 20-29.

Research output: Contribution to journalArticle

@article{3a9131e708c04392b48511e8e26fbe2b,
title = "Conformational composition of neutral leucine. Matrix isolation infrared and ab initio study",
abstract = "Low-temperature matrix-isolation FTIR spectroscopy and ab initio calculations are employed to determine conformational composition of neutral leucine. The presence of three leucine conformers in the matrices is revealed. This is in agreement with the results of a detailed study of the potential energy surface of leucine which demonstrates that only five out of 105 possible conformers should have populations in the matrices larger than 2{\%} and only three conformers, which are the ones detected in the experiment, should have populations larger than 10{\%}. UV irradiation of the matrix samples are used to separate bands of the different conformers. We also show that the populations of the leucine conformers in the gas phase at 440 K are significantly different from the ones in matrices. The population of the lowest energy con- former in the gas phase being approximately 23{\%} in the gas phase increases to over 64{\%} in matrices.",
keywords = "Ab initio calculations, Conformer interconversion, Gibbs free energies, IR spectroscopy, Leucine, Matrix isolation",
author = "Stepanian, {Stepan G.} and Ivanov, {Alexander Yu} and Ludwik Adamowicz",
year = "2013",
doi = "10.1016/j.chemphys.2013.06.018",
language = "English (US)",
volume = "423",
pages = "20--29",
journal = "Chemical Physics",
issn = "0301-0104",
publisher = "Elsevier",

}

TY - JOUR

T1 - Conformational composition of neutral leucine. Matrix isolation infrared and ab initio study

AU - Stepanian, Stepan G.

AU - Ivanov, Alexander Yu

AU - Adamowicz, Ludwik

PY - 2013

Y1 - 2013

N2 - Low-temperature matrix-isolation FTIR spectroscopy and ab initio calculations are employed to determine conformational composition of neutral leucine. The presence of three leucine conformers in the matrices is revealed. This is in agreement with the results of a detailed study of the potential energy surface of leucine which demonstrates that only five out of 105 possible conformers should have populations in the matrices larger than 2% and only three conformers, which are the ones detected in the experiment, should have populations larger than 10%. UV irradiation of the matrix samples are used to separate bands of the different conformers. We also show that the populations of the leucine conformers in the gas phase at 440 K are significantly different from the ones in matrices. The population of the lowest energy con- former in the gas phase being approximately 23% in the gas phase increases to over 64% in matrices.

AB - Low-temperature matrix-isolation FTIR spectroscopy and ab initio calculations are employed to determine conformational composition of neutral leucine. The presence of three leucine conformers in the matrices is revealed. This is in agreement with the results of a detailed study of the potential energy surface of leucine which demonstrates that only five out of 105 possible conformers should have populations in the matrices larger than 2% and only three conformers, which are the ones detected in the experiment, should have populations larger than 10%. UV irradiation of the matrix samples are used to separate bands of the different conformers. We also show that the populations of the leucine conformers in the gas phase at 440 K are significantly different from the ones in matrices. The population of the lowest energy con- former in the gas phase being approximately 23% in the gas phase increases to over 64% in matrices.

KW - Ab initio calculations

KW - Conformer interconversion

KW - Gibbs free energies

KW - IR spectroscopy

KW - Leucine

KW - Matrix isolation

UR - http://www.scopus.com/inward/record.url?scp=84885668898&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84885668898&partnerID=8YFLogxK

U2 - 10.1016/j.chemphys.2013.06.018

DO - 10.1016/j.chemphys.2013.06.018

M3 - Article

AN - SCOPUS:84885668898

VL - 423

SP - 20

EP - 29

JO - Chemical Physics

JF - Chemical Physics

SN - 0301-0104

ER -