ADSORPTION OF 4-METHOXYBENZYL CYANIDE ON SILVER AND GOLD SURFACES INVESTIGATED BY FOURIER-TRANSFORM INFRARED-SPECTROSCOPY

The adsorption of 4-methoxybenzyl cyanide (4MBC) on gold and silver surfaces has been investigated by infrared spectroscopy. The molecule was found to adsorb on both surfaces via the CN pi system. The benzene ring of 4MBC on gold appeared to assume a more perpendicular stance with respect to the surface than that on silver. At the gold electrode, a minimal amount of surface reaction seemed to occur to produce CN- species. Otherwise, the orientation of 4MBC adsorbed on gold was insensitive to the electrode potential. On the other hand, any surface reaction hardly appeared to occur at the silver electrode. However, upon the potential variation, the adsorbate structure seemed to change greatly by rotating through the NC-CH2 and H2C-C6H4 bond axes. Namely, at higher potentials, the benzene ring of adsorbed 4MBC seemed to take a more parallel stance with respect to the silver surface.