In Situ Raman Spectroscopy of Redox Species Confined in Self-Assembled Molecular Films
| Autor: | María Elena Vela, Carolina Vericat, Alejandro Fainstein, Nicolás G. Tognalli, Roberto Carlos Salvarezza |
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| Rok vydání: | 2008 |
| Předmět: |
Chemistry
Inorganic chemistry Propanethiol Substrate (chemistry) Redox Surfaces Coatings and Films Electronic Optical and Magnetic Materials symbols.namesake Electron transfer chemistry.chemical_compound General Energy Desorption Monolayer Molecular film symbols Physical and Theoretical Chemistry Raman spectroscopy |
| Zdroj: | The Journal of Physical Chemistry C. 112:3741-3746 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp076239k |
| Popis: | In situ Raman spectroscopy and electrochemical experiments are used to study different methylene blue (MB) species immobilized in molecular films (sulfur, propanethiol, dodecanethiol, mercaptopropionic acid, and mercaptoundecanoic acid monolayers), self-assembled on SERS-active Au surfaces in aqueous electrolyte under potential control. The presence of three different MB species along reduction−oxidation cycles is inferred, irrespective of the nature of the molecular film. Residual Raman intensity in the spectroscopically silent leuco methylene blue (LMB) potential range demonstrate a dissimilar degree of connectivity for electron transfer between MB molecules and substrate depending on the spacer. In addition, the intensity of the Raman signal depends on the monolayer chemistry where hydrophobic and/or electrostatic interactions tend to stabilize the MB species against desorption from the molecular film driven by concentration gradients. |
| Databáze: | OpenAIRE |
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