Theoretical study of aryl-ring rotation in arylporphyrins

Yoshishige Okuno, Toshiya Kamikado, Shiyoshi Yokoyama, Shinro Mashiko

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

We carried out quantum chemical calculations for the aryl-ring rotations in phenylporphyrin and ortho-methoxyphenylporphyrin to determine the reaction path and the potential-energy barrier so that one can provide an insight into how such rotations can occur. It was found that along the reaction path, the structure changes from a planar porphyrin-ring at the stable state to a considerably distorted one at the transition state, and that the small potential-energy barrier, which is consistent with experiments, largely stems from the deformation of the porphyrin ring. An increase in the potential-energy barrier resulting from the substitution at the ortho position of the aryl group was also found to originate mainly from an additional deformation of the porphyrin ring at the transition state. These findings are in contrast with the calculated result for the aryl-ring rotation in the biphenyl, in which the direct steric hindrance between the aryl rings rather than the deformation makes large contributions to the overall potential energy barrier. We concluded that the deformation of the porphyrin ring is essential for the occurrence of the aryl-ring rotation in the arylporphyrins.

Original languageEnglish
Pages (from-to)55-60
Number of pages6
JournalJournal of Molecular Structure: THEOCHEM
Volume594
Issue number1-2
DOIs
Publication statusPublished - Oct 11 2002
Externally publishedYes

Fingerprint

Energy barriers
Porphyrins
Potential energy
Theoretical Models
rings
porphyrins
potential energy
Substitution reactions
stems
Experiments
occurrences
substitutes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Cite this

Theoretical study of aryl-ring rotation in arylporphyrins. / Okuno, Yoshishige; Kamikado, Toshiya; Yokoyama, Shiyoshi; Mashiko, Shinro.

In: Journal of Molecular Structure: THEOCHEM, Vol. 594, No. 1-2, 11.10.2002, p. 55-60.

Research output: Contribution to journalArticle

Okuno, Yoshishige ; Kamikado, Toshiya ; Yokoyama, Shiyoshi ; Mashiko, Shinro. / Theoretical study of aryl-ring rotation in arylporphyrins. In: Journal of Molecular Structure: THEOCHEM. 2002 ; Vol. 594, No. 1-2. pp. 55-60.
@article{1c05810d889b40eebe4ad42abb6193d6,
title = "Theoretical study of aryl-ring rotation in arylporphyrins",
abstract = "We carried out quantum chemical calculations for the aryl-ring rotations in phenylporphyrin and ortho-methoxyphenylporphyrin to determine the reaction path and the potential-energy barrier so that one can provide an insight into how such rotations can occur. It was found that along the reaction path, the structure changes from a planar porphyrin-ring at the stable state to a considerably distorted one at the transition state, and that the small potential-energy barrier, which is consistent with experiments, largely stems from the deformation of the porphyrin ring. An increase in the potential-energy barrier resulting from the substitution at the ortho position of the aryl group was also found to originate mainly from an additional deformation of the porphyrin ring at the transition state. These findings are in contrast with the calculated result for the aryl-ring rotation in the biphenyl, in which the direct steric hindrance between the aryl rings rather than the deformation makes large contributions to the overall potential energy barrier. We concluded that the deformation of the porphyrin ring is essential for the occurrence of the aryl-ring rotation in the arylporphyrins.",
author = "Yoshishige Okuno and Toshiya Kamikado and Shiyoshi Yokoyama and Shinro Mashiko",
year = "2002",
month = "10",
day = "11",
doi = "10.1016/S0166-1280(02)00336-6",
language = "English",
volume = "594",
pages = "55--60",
journal = "Computational and Theoretical Chemistry",
issn = "2210-271X",
publisher = "Elsevier BV",
number = "1-2",

}

TY - JOUR

T1 - Theoretical study of aryl-ring rotation in arylporphyrins

AU - Okuno, Yoshishige

AU - Kamikado, Toshiya

AU - Yokoyama, Shiyoshi

AU - Mashiko, Shinro

PY - 2002/10/11

Y1 - 2002/10/11

N2 - We carried out quantum chemical calculations for the aryl-ring rotations in phenylporphyrin and ortho-methoxyphenylporphyrin to determine the reaction path and the potential-energy barrier so that one can provide an insight into how such rotations can occur. It was found that along the reaction path, the structure changes from a planar porphyrin-ring at the stable state to a considerably distorted one at the transition state, and that the small potential-energy barrier, which is consistent with experiments, largely stems from the deformation of the porphyrin ring. An increase in the potential-energy barrier resulting from the substitution at the ortho position of the aryl group was also found to originate mainly from an additional deformation of the porphyrin ring at the transition state. These findings are in contrast with the calculated result for the aryl-ring rotation in the biphenyl, in which the direct steric hindrance between the aryl rings rather than the deformation makes large contributions to the overall potential energy barrier. We concluded that the deformation of the porphyrin ring is essential for the occurrence of the aryl-ring rotation in the arylporphyrins.

AB - We carried out quantum chemical calculations for the aryl-ring rotations in phenylporphyrin and ortho-methoxyphenylporphyrin to determine the reaction path and the potential-energy barrier so that one can provide an insight into how such rotations can occur. It was found that along the reaction path, the structure changes from a planar porphyrin-ring at the stable state to a considerably distorted one at the transition state, and that the small potential-energy barrier, which is consistent with experiments, largely stems from the deformation of the porphyrin ring. An increase in the potential-energy barrier resulting from the substitution at the ortho position of the aryl group was also found to originate mainly from an additional deformation of the porphyrin ring at the transition state. These findings are in contrast with the calculated result for the aryl-ring rotation in the biphenyl, in which the direct steric hindrance between the aryl rings rather than the deformation makes large contributions to the overall potential energy barrier. We concluded that the deformation of the porphyrin ring is essential for the occurrence of the aryl-ring rotation in the arylporphyrins.

UR - http://www.scopus.com/inward/record.url?scp=0037063771&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037063771&partnerID=8YFLogxK

U2 - 10.1016/S0166-1280(02)00336-6

DO - 10.1016/S0166-1280(02)00336-6

M3 - Article

AN - SCOPUS:0037063771

VL - 594

SP - 55

EP - 60

JO - Computational and Theoretical Chemistry

JF - Computational and Theoretical Chemistry

SN - 2210-271X

IS - 1-2

ER -