characterization of mercaptobenzimidazole adsorption on an au(111) electrode

the adsorption of 2-mercaptobenzimidazole (2-mbi) on au(111) has been studied withcyclic voltammetry (cv), in-situ subtractively normalised interfacial ft-ir spectroscopy (sniftirs)and scanning tunnelling microscopy (stm). although adsorbed 2-mbi reduces the interfacial capacityand quenches the characteristic features of the cyclic voltammogram for sulfate adsorption,heterogeneous electron transfer to both the [fe(cn)6]4-/3- and [ru(nh3)6]3+/2+ redox systems is onlypartially impeded. cyclic voltammetry has also been used to examine the reductive desorption of thethiolate in koh electrolytes and its subsequent re-adsorption. from the reductive desorption charge,coverage of 2-mbi of 2.6 x 10-10 molecule cm-2 is estimated and this points to a flat-lying configurationof the monolayer, in agreement with a previous xps study. the sniftirs and electrochemical resultsshow that adsorbed 2-mbi is displaced from the surface at positive potentials. stm imaging of adsorbed2-mbi is also consistent with flat-lying molecules aligned in parallel rows.