Electrochemical study of Schiff bases by means of self-assembled monolayers

In this paper, Schiff bases were investigated using cyclic voltammetry (CV) and impedance electrochemical spectroscopy (EIS) techniques by means of self-assembled monolayers for the first time, where a 0.1 M KCl solution and the redox couple of Fe(CN)_63-/Fe(CN)₆^4- were used as the selectrolyte and probing-pin, respectively. The monolayers formed by the employed Schiff base were proved to be relatively stable, and its electrochemical response in the studied system with different pH values was also described clearly with CV and EIS plots. The results show that the monolayer of Schiff bases could exist in the solution with pH value from 2 to 10. In the EIS measurement in the concentration range from 10^-5 M to 5 × 10^-4 M, a nearly linear relationship between the charge transfer resistance (R_ct) and the logarithm concentration of Cu^2t was observed, suggesting that Cu^2t could be titrated with the EIS method quasi-quantitatively. The phenomenon agreed with the former report very well. Using the self-assembled monolayers to study Schiff bases with the electrochemical method is the major contribution of our work.