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 su rfaces has been investigated by infrared spectroscopy. The molecule wa s found to adsorb on both surfaces via the CN pi system. The benzene r ing of 4MBC on gold appeared to assume a more perpendicular stance wit h respect to the surface than that on silver. At the gold electrode, a minimal amount of surface reaction seemed to occur to produce CN- spe cies. Otherwise, the orientation of 4MBC adsorbed on gold was insensit ive to the electrode potential. On the other hand, any surface reactio n 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 high er potentials, the benzene ring of adsorbed 4MBC seemed to take a more parallel stance with respect to the silver surface.