The chemical dynamics of symmetric and asymmetric reaction coordinates

Saul Wolfe, H. Bernhard Schlegel, I. Csizmadia, Fernando Bernardi

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The question has been posed as to whether a rotation-inversion process that results in the interconversion of two enantiomeric or identical species can be described by a unique asymmetric reaction coordinate. It is shown that the methods of classical kinetics and reaction dynamics are unable to solve this problem rigorously. A quantum mechanical analysis, employing the symmetry properties of the reaction surface, has therefore been developed, and applied to two cases: case I, in which one transition state separates reagents and products; and case II, in which a stable intermediate appears on the reaction coordinate. It is found that no unique path exists for the case I situation, i.e.. that all asymmetric reaction coordinates are indistinguishable. This conclusion holds under equilibrium conditions, under nonequilibrium conditions, and under photochemical excitation. The analysis developed to describe the equilibrium situation of case I constitutes a quantum mechanical demonstration of the principle of microscopic reversibility. For the case II situation, it is found that distinguishable asymmetric paths can exist under nonequilibrium conditions. These are related to each other in a diastereomeric sense, in contrast to case I, in which various reaction paths differ in an enantiomeric sense.

Original languageEnglish
Pages (from-to)2020-2024
Number of pages5
JournalJournal of the American Chemical Society
Volume97
Issue number8
Publication statusPublished - 1975

Fingerprint

Surface Properties
Surface reactions
Demonstrations
Kinetics

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

The chemical dynamics of symmetric and asymmetric reaction coordinates. / Wolfe, Saul; Schlegel, H. Bernhard; Csizmadia, I.; Bernardi, Fernando.

In: Journal of the American Chemical Society, Vol. 97, No. 8, 1975, p. 2020-2024.

Research output: Contribution to journalArticle

Wolfe, Saul ; Schlegel, H. Bernhard ; Csizmadia, I. ; Bernardi, Fernando. / The chemical dynamics of symmetric and asymmetric reaction coordinates. In: Journal of the American Chemical Society. 1975 ; Vol. 97, No. 8. pp. 2020-2024.
@article{575a24874d04459ebfff003d5a16562f,
title = "The chemical dynamics of symmetric and asymmetric reaction coordinates",
abstract = "The question has been posed as to whether a rotation-inversion process that results in the interconversion of two enantiomeric or identical species can be described by a unique asymmetric reaction coordinate. It is shown that the methods of classical kinetics and reaction dynamics are unable to solve this problem rigorously. A quantum mechanical analysis, employing the symmetry properties of the reaction surface, has therefore been developed, and applied to two cases: case I, in which one transition state separates reagents and products; and case II, in which a stable intermediate appears on the reaction coordinate. It is found that no unique path exists for the case I situation, i.e.. that all asymmetric reaction coordinates are indistinguishable. This conclusion holds under equilibrium conditions, under nonequilibrium conditions, and under photochemical excitation. The analysis developed to describe the equilibrium situation of case I constitutes a quantum mechanical demonstration of the principle of microscopic reversibility. For the case II situation, it is found that distinguishable asymmetric paths can exist under nonequilibrium conditions. These are related to each other in a diastereomeric sense, in contrast to case I, in which various reaction paths differ in an enantiomeric sense.",
author = "Saul Wolfe and Schlegel, {H. Bernhard} and I. Csizmadia and Fernando Bernardi",
year = "1975",
language = "English",
volume = "97",
pages = "2020--2024",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "8",

}

TY - JOUR

T1 - The chemical dynamics of symmetric and asymmetric reaction coordinates

AU - Wolfe, Saul

AU - Schlegel, H. Bernhard

AU - Csizmadia, I.

AU - Bernardi, Fernando

PY - 1975

Y1 - 1975

N2 - The question has been posed as to whether a rotation-inversion process that results in the interconversion of two enantiomeric or identical species can be described by a unique asymmetric reaction coordinate. It is shown that the methods of classical kinetics and reaction dynamics are unable to solve this problem rigorously. A quantum mechanical analysis, employing the symmetry properties of the reaction surface, has therefore been developed, and applied to two cases: case I, in which one transition state separates reagents and products; and case II, in which a stable intermediate appears on the reaction coordinate. It is found that no unique path exists for the case I situation, i.e.. that all asymmetric reaction coordinates are indistinguishable. This conclusion holds under equilibrium conditions, under nonequilibrium conditions, and under photochemical excitation. The analysis developed to describe the equilibrium situation of case I constitutes a quantum mechanical demonstration of the principle of microscopic reversibility. For the case II situation, it is found that distinguishable asymmetric paths can exist under nonequilibrium conditions. These are related to each other in a diastereomeric sense, in contrast to case I, in which various reaction paths differ in an enantiomeric sense.

AB - The question has been posed as to whether a rotation-inversion process that results in the interconversion of two enantiomeric or identical species can be described by a unique asymmetric reaction coordinate. It is shown that the methods of classical kinetics and reaction dynamics are unable to solve this problem rigorously. A quantum mechanical analysis, employing the symmetry properties of the reaction surface, has therefore been developed, and applied to two cases: case I, in which one transition state separates reagents and products; and case II, in which a stable intermediate appears on the reaction coordinate. It is found that no unique path exists for the case I situation, i.e.. that all asymmetric reaction coordinates are indistinguishable. This conclusion holds under equilibrium conditions, under nonequilibrium conditions, and under photochemical excitation. The analysis developed to describe the equilibrium situation of case I constitutes a quantum mechanical demonstration of the principle of microscopic reversibility. For the case II situation, it is found that distinguishable asymmetric paths can exist under nonequilibrium conditions. These are related to each other in a diastereomeric sense, in contrast to case I, in which various reaction paths differ in an enantiomeric sense.

UR - http://www.scopus.com/inward/record.url?scp=0039207937&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0039207937&partnerID=8YFLogxK

M3 - Article

VL - 97

SP - 2020

EP - 2024

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 8

ER -