Faradaic impedance titration and control of electron transfer of 1-(12-mercaptododecyl)imidazole monolayer on a gold electrode

Seongpil Hwang, Bang Sook Lee, Young Shik Chi, Juhyoun Kwak, Insung S. Choi, Sang gi Lee

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

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 languageEnglish
Pages (from-to)2630-2636
Number of pages7
JournalElectrochimica Acta
Volume53
Issue number5
DOIs
StatePublished - 1 Jan 2008

Keywords

  • 1-(12-Mercaptododecyl)imidazole
  • Electron transfer
  • Electrostatic interaction
  • Faradaic impedance titration
  • Self-assembled monolayer
  • Surface pK

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