An Initial Study of Coating Nickel Salen on Gold Electrode via Self-Assembly

Abstract

Two novel nickel(II) salens modified with a side alkanethiol chain containing either six or eight methylene groups (Ni(II)L-(CH2)6SH or Ni(II)L-(CH2)8SH) were obtained by a multistep synthetic route. The catalysts were used to coat the gold electrode via self-assembly with the formation of a compact monolayer. Cyclic voltammetry (CV) was employed to examine the electrochemical properties of the immobilized nickel salen molecules, which have been found to undergo oxidative polymerization at the gold surface. The resulting polymerized catalyst film, which is fairly stable and robust, can efficiently block the diffusion of ferrocene to the electrode surface. Moreover, a new redox CV feature was observed for the polymerized nickel salen, which can be potentially applied for various catalytic reduction or oxidation reactions. This initial study shows that it is feasible to immobilize metal Schiff base complexes on gold electrode using alkanethiol substituents as the anchors for the development of analytical sensors.