Electrochemical Behavior of Ferrocenylthiol / Alkanethiol Binary SAM in Ionic Liquids

摘要

The redox behavior of the binary self-assembled monolayers (SAMs) of 11-ferrocenyl-1-undecanethiol and 1-undecanthiol on gold substrate was investigated in an ionic liquid (IL), trimethyl-n--hexylammonium bis[(trifluoromethyl)sulfonyl]amide (TMHA-Tf_zN) and HClO_4 aqueous solution. It was found that the total amount of charge for the redox of ferrocenyl groups in the ionic liquid is about 70% of that in the HClO_4 solution, indicating that less number of ferrocenyl groups are involved in the redox in the ionic liquid. A set of impedance measurements indicated that the electron transfer rate between the SAMs and the substrate is lower in the ionic liquid than that in aqueous solution, suggesting a slow and incomplete reconstruction of TMHA-Tf_2N ions at the SAMs/ionic liquid surface.