Synthesis and Electrochemical Studies of a Ferrocene Derivative for the Application to Metal Ion Sensor

The combination of electrochemically active ferrocene and thioether-amine as a metal ion recognition site has formed an electrochemical sensor for metal ions. With an aim to apply the ferrocene derivative toward electrochemical sensing devices for heavy metal ions, electrochemical properties of 2-((bis(2-(ethylthio)ethyl)- amino)methyl)-N-ferrocenylmethyl aniline A were examined in the presence of Hg2+, Cd2+, Zn2+, and Mg2+. The cathodic oxidation potential shift of compound A was observed as ΔEpa = 276 mV in CH3CN (0.1 M LiClO4) with an equimolar Hg2+. The binding constant of compound A with Hg2+ was measured as Ka = 8100 M−1 in CH3CN via UV-vis absorbance spectroscopy. With the electrochemical and spectroscopic data, the binding event is speculated to occur at the tertiary amine proximal to the sulfide functional groups in compound A with the modest affinity.