Low energy barriers of H-atom abstraction from phenols

Oksana Tishchenko; Eugene S. Kryachko; Minh Tho Nguyen

doi:10.1016/S0022-2860(02)00225-9

Low energy barriers of H-atom abstraction from phenols

Oksana Tishchenko, Eugene S. Kryachko, Minh Tho Nguyen

Chemistry (Twin Cities)

Research output: Contribution to journal › Article › peer-review

14 Scopus citations

Abstract

The energy barriers governing the hydrogen atom transfer between phenols related to Vitamin E and methylperoxyl radical are determined using the B3LYP/6-31G(d,p) method. For phenol, o,o-dimethylphenol, and o,o,m-trimethylphenol, they are equal to 6.0, 4.2, and 3.5 kcal/mol, respectively. While in both reactants and products the H-bond is nearly coplanar with the aromatic ring, it becomes essentially twisted out of the ring in the transition state structures. This implies that the transition states in such reactions are likely located at the avoided crossing of the lower-lying electronic states of the H-bonded complex, correlating with the ground π and first excited σ states of the incipient phenoxyl radical.

Original language	English (US)
Pages (from-to)	247-250
Number of pages	4
Journal	Journal of Molecular Structure
Volume	615
Issue number	1-3
DOIs	https://doi.org/10.1016/S0022-2860(02)00225-9
State	Published - Sep 26 2002

Bibliographical note

Funding Information:
The support of the KU Leuven Research Council (GOA program) is gratefully acknowledged. The authors thank the referee for valuable comments and suggestions.

Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.

Keywords

Antioxidants
Hydrogen atom transfer
Hydrogen bonding
Phenols
Potential energy surface

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title = "Low energy barriers of H-atom abstraction from phenols",

abstract = "The energy barriers governing the hydrogen atom transfer between phenols related to Vitamin E and methylperoxyl radical are determined using the B3LYP/6-31G(d,p) method. For phenol, o,o-dimethylphenol, and o,o,m-trimethylphenol, they are equal to 6.0, 4.2, and 3.5 kcal/mol, respectively. While in both reactants and products the H-bond is nearly coplanar with the aromatic ring, it becomes essentially twisted out of the ring in the transition state structures. This implies that the transition states in such reactions are likely located at the avoided crossing of the lower-lying electronic states of the H-bonded complex, correlating with the ground π and first excited σ states of the incipient phenoxyl radical.",

keywords = "Antioxidants, Hydrogen atom transfer, Hydrogen bonding, Phenols, Potential energy surface",

author = "Oksana Tishchenko and Kryachko, {Eugene S.} and Nguyen, {Minh Tho}",

note = "Funding Information: The support of the KU Leuven Research Council (GOA program) is gratefully acknowledged. The authors thank the referee for valuable comments and suggestions. Copyright: Copyright 2008 Elsevier B.V., All rights reserved.",

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AU - Kryachko, Eugene S.

AU - Nguyen, Minh Tho

N1 - Funding Information: The support of the KU Leuven Research Council (GOA program) is gratefully acknowledged. The authors thank the referee for valuable comments and suggestions. Copyright: Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2002/9/26

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N2 - The energy barriers governing the hydrogen atom transfer between phenols related to Vitamin E and methylperoxyl radical are determined using the B3LYP/6-31G(d,p) method. For phenol, o,o-dimethylphenol, and o,o,m-trimethylphenol, they are equal to 6.0, 4.2, and 3.5 kcal/mol, respectively. While in both reactants and products the H-bond is nearly coplanar with the aromatic ring, it becomes essentially twisted out of the ring in the transition state structures. This implies that the transition states in such reactions are likely located at the avoided crossing of the lower-lying electronic states of the H-bonded complex, correlating with the ground π and first excited σ states of the incipient phenoxyl radical.

AB - The energy barriers governing the hydrogen atom transfer between phenols related to Vitamin E and methylperoxyl radical are determined using the B3LYP/6-31G(d,p) method. For phenol, o,o-dimethylphenol, and o,o,m-trimethylphenol, they are equal to 6.0, 4.2, and 3.5 kcal/mol, respectively. While in both reactants and products the H-bond is nearly coplanar with the aromatic ring, it becomes essentially twisted out of the ring in the transition state structures. This implies that the transition states in such reactions are likely located at the avoided crossing of the lower-lying electronic states of the H-bonded complex, correlating with the ground π and first excited σ states of the incipient phenoxyl radical.

KW - Antioxidants

KW - Hydrogen atom transfer

KW - Hydrogen bonding

KW - Phenols

KW - Potential energy surface

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Low energy barriers of H-atom abstraction from phenols

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Keywords

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