Long-range electron-transfer reaction rates to cytochrome c across long- and short-chain alkanethiol self-assembled monolayers

Electroreflectance studies

Zhi Qiang Feng, Shinichiro Imabayashi, Takashi Kakiuchi, Katsumi Niki

Research output: Contribution to journalArticle

138 Citations (Scopus)

Abstract

The kinetics of electron transfer (ET) between cytochrome c and a gold (111) electrode through self-assembled monolayers of alkanethiols with terminal carboxylic acid groups, COOH(CH2)nSH, have been studied for n = 2-11 using an ac potential-modulated UV-VIS reflectance spectroscopic technique (electroreflectance spectroscopy, ER). For 9 ≤ n ≤ 11, the standard ET rate constant, kapp, depends exponentially on the chain lengths and the exponential decay factor is 1.09 per methylene group; for n < 9, however, kapp deviates from the exponential plot. The ET reaction through short-chain alkanethiol monolayers is controlled by the preceding chemical reaction. The rate-controlling step is very likely to be the reorganization of cytochrome c to the favourable conformation for the ET reaction. The ET reaction rate constant from cytochrome c in the favourable conformation to the electrode surface obeys Marcus theory for long-range ET. The ET reaction through long-chain alkanethiol monolayers is controlled by the ET rate through alkanethiols.

Original languageEnglish
Pages (from-to)1367-1370
Number of pages4
JournalJournal of the Chemical Society - Faraday Transactions
Volume93
Issue number7
Publication statusPublished - 1997 Apr 7
Externally publishedYes

Fingerprint

cytochromes
Self assembled monolayers
Cytochromes c
Reaction rates
electron transfer
reaction kinetics
Electrons
Conformations
Monolayers
Rate constants
Cytochromes a
Electrodes
electrodes
Carboxylic Acids
Chain length
methylene
carboxylic acids
Gold
Chemical reactions
chemical reactions

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

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title = "Long-range electron-transfer reaction rates to cytochrome c across long- and short-chain alkanethiol self-assembled monolayers: Electroreflectance studies",
abstract = "The kinetics of electron transfer (ET) between cytochrome c and a gold (111) electrode through self-assembled monolayers of alkanethiols with terminal carboxylic acid groups, COOH(CH2)nSH, have been studied for n = 2-11 using an ac potential-modulated UV-VIS reflectance spectroscopic technique (electroreflectance spectroscopy, ER). For 9 ≤ n ≤ 11, the standard ET rate constant, kapp, depends exponentially on the chain lengths and the exponential decay factor is 1.09 per methylene group; for n < 9, however, kapp deviates from the exponential plot. The ET reaction through short-chain alkanethiol monolayers is controlled by the preceding chemical reaction. The rate-controlling step is very likely to be the reorganization of cytochrome c to the favourable conformation for the ET reaction. The ET reaction rate constant from cytochrome c in the favourable conformation to the electrode surface obeys Marcus theory for long-range ET. The ET reaction through long-chain alkanethiol monolayers is controlled by the ET rate through alkanethiols.",
author = "Feng, {Zhi Qiang} and Shinichiro Imabayashi and Takashi Kakiuchi and Katsumi Niki",
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T1 - Long-range electron-transfer reaction rates to cytochrome c across long- and short-chain alkanethiol self-assembled monolayers

T2 - Electroreflectance studies

AU - Feng, Zhi Qiang

AU - Imabayashi, Shinichiro

AU - Kakiuchi, Takashi

AU - Niki, Katsumi

PY - 1997/4/7

Y1 - 1997/4/7

N2 - The kinetics of electron transfer (ET) between cytochrome c and a gold (111) electrode through self-assembled monolayers of alkanethiols with terminal carboxylic acid groups, COOH(CH2)nSH, have been studied for n = 2-11 using an ac potential-modulated UV-VIS reflectance spectroscopic technique (electroreflectance spectroscopy, ER). For 9 ≤ n ≤ 11, the standard ET rate constant, kapp, depends exponentially on the chain lengths and the exponential decay factor is 1.09 per methylene group; for n < 9, however, kapp deviates from the exponential plot. The ET reaction through short-chain alkanethiol monolayers is controlled by the preceding chemical reaction. The rate-controlling step is very likely to be the reorganization of cytochrome c to the favourable conformation for the ET reaction. The ET reaction rate constant from cytochrome c in the favourable conformation to the electrode surface obeys Marcus theory for long-range ET. The ET reaction through long-chain alkanethiol monolayers is controlled by the ET rate through alkanethiols.

AB - The kinetics of electron transfer (ET) between cytochrome c and a gold (111) electrode through self-assembled monolayers of alkanethiols with terminal carboxylic acid groups, COOH(CH2)nSH, have been studied for n = 2-11 using an ac potential-modulated UV-VIS reflectance spectroscopic technique (electroreflectance spectroscopy, ER). For 9 ≤ n ≤ 11, the standard ET rate constant, kapp, depends exponentially on the chain lengths and the exponential decay factor is 1.09 per methylene group; for n < 9, however, kapp deviates from the exponential plot. The ET reaction through short-chain alkanethiol monolayers is controlled by the preceding chemical reaction. The rate-controlling step is very likely to be the reorganization of cytochrome c to the favourable conformation for the ET reaction. The ET reaction rate constant from cytochrome c in the favourable conformation to the electrode surface obeys Marcus theory for long-range ET. The ET reaction through long-chain alkanethiol monolayers is controlled by the ET rate through alkanethiols.

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