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| Accueil>La recherche>nanosciences>chimie>Electrochemistry | ||||||||||||||
ELECTROCHEMICAL ELECTRON TRANSFER TROUGH SELF-ASSEMBLED-MONOLAYERS
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 Figure 1 |
We are currently involved in a research program concerning electron transfer (ET) processes between an electrode and a redox site through an organic linker (see Figure 1). Since this organic linker is connected on one end to a redox site, and on the other end to an electrode, this type of experiment bridges the gap between mixed valence electron transfer (where the molecular wire connects two metal atoms) and the nanojunction experiment (where the molecular wire connects two metal electrodes). |
| The electron transfer occurs through a self-assembled monolayer (SAM), made of alkanethiols chemisorbed on the electrode, in which ‘active molecules” have been dispersed. While most published work involves ferrocene as redox site, we presently investigate systems with ruthenium cyclometallated derivatives as redox sites (see Figure 2). |
 Figure 2 |
 Figure 3 |
The detection of electron transfer between the electrode and the redox site are performed by electrochemical impedance measurements, according to a method devised by S. Creager (Pasadena)1. The ET rate constant is extracted from ac voltammograms acquired at different frequencies (see Figure 3). We have shown that redox active molecules containing the cyclometallated ruthenium complex exhibit higher ET rate constants, compared to ferrocene derivatives, due to the weak reorganisation energy of this complex2. |
Keywords : Electron transfer, Self Assembled Monolayers, ruthenium complex, impedance spectroscopy. links : Long Distance Intervalence Electron Transfer , Tunnel Transport . |
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