ELECTROCHEMICAL BEHAVIORS OF FERROCENE DERIVATIVES AT AN ELECTRODE MODIFIED WITH TERMINALLY SUBSTITUTED ALKANETHIOL MONOLAYER ASSEMBLIES

Self-assembled monolayers of 11-mercapto-1-undecanol (MUO), 11-mercaptoundecanoic acid (MUA), and 11-amino-1-undecanethiol (AUT) were formed on a gold disk electrode. The effects of the terminal charges of these monolayers on the redox responses of 1,1'-ferrocenedimethanol (FcDM), (ferrocenylmethyl)trimethylammoniun bromide (FcMA) and ammonium ferrocenesulfonate (FcSA) were evaluated by using voltammetric (CV) techniques. The CV responses of FcDM and FcMA decreased in the order of MUA/Au (MUA modified gold electrode), MUO/Au, and AUT/Au. In contrast, the CV response of FcSA increased in the order of MUA/Au, MUO/Au, and AUT/Au. From these results, the effects of the terminal charges on the CV responses were measured in relation to the diffuse layer potential and the electrostatic interaction between the terminal unit and redox species.