Electrochemical SERS Studies on the Adsorption of Benzoimidazole and Derivative in Nonaqueous Solution

The surface adsorption of benzoimidazole (BIMH) and 2-mercaptobenzimidazole( MBI) was investigated by electrochemical in-situ surface enhanced Raman spectroscopy (SERS) and direct electrochemical synthesis on Cu electrode. The influence of the neutral ligand of triphenylphosphine (pph3) on the adsorption and surface coordination of BIMH and MBI were investigated respectively. BIMH interacted with metal surface by the neutral molecule to form chemical adlayer in the extremely negative potential,while it adsorbed onto metal surface through the N atoms to form a polymer film which may suppress the corrosion of the metal. The introduction of pph3 destroyed the film formation of BIMH on Cu electrode through the production of dissoluble cation of Cu + and pph3. MBI was adsorbed onto Cu surface by self assemble monolayer through S atom at the full potential range. The orientation underwent a transformation from tilt to vertical to electrode surface when the potential was shifted in positive direction. No influence of pph3 was placed on the adsorption behavior. The results deduced from the in-situ spectroscopic studies were in good agreement with the structural information from the complexes synthesized by electrochemical method.