Abstract
In this work, we studied interfacial proton transfer of the self-assembled monolayer (SAM) of 1-(12-mercaptododecyl)imidazole on a gold electrode by faradaic impedance titration method with Fe(CN)63- as an anionic redox probe molecule. The surface pK1/2 was found to be 7.3, which was nearly the same as that of 1-alkylimidazole in solution. We also investigated the electrochemical properties of the SAM-modified electrode by cyclic voltammetry. Cyclic voltammetry was performed (1) in the solution containing Fe(CN)63- with repeated alternation of pH values to investigate the electrostatic interaction of the protonated or deprotonated imidazole with Fe(CN)63- and (2) in the acidic or basic electrolyte containing Ru(NH3)63+ as a cationic redox probe to verify the effect of the polarity of a redox probe. We observed the reversible adsorption/desorption of Fe(CN)63- and concluded that the adsorbed Fe(CN)63- catalyzed the electron transfer of both Fe(CN)63- itself and cationic Ru(NH3)63+.
Original language | English |
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Pages (from-to) | 2630-2636 |
Number of pages | 7 |
Journal | Electrochimica Acta |
Volume | 53 |
Issue number | 5 |
DOIs | |
State | Published - 1 Jan 2008 |
Bibliographical note
Funding Information:This work was supported by the Center for Molecular Design and Synthesis at KAIST (I.S.C. and S.-g.L.), Seoul R&BD Program (10816) (S.-g.L.), and Bioelectronics Program (M10536000001-06N3600-00110) (J.K.). We thank Dr. Jong-Seong Bae and Dr. Myoung-gyu Ha in Korea Basic Science Institute (KBSI) for the XPS analysis.
Keywords
- 1-(12-Mercaptododecyl)imidazole
- Electron transfer
- Electrostatic interaction
- Faradaic impedance titration
- Self-assembled monolayer
- Surface pK