TY - JOUR
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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U2 - 10.1039/a605567b
DO - 10.1039/a605567b
M3 - Article
AN - SCOPUS:33748608019
VL - 93
SP - 1367
EP - 1370
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 7
ER -