A SERS spectroelectrochemical investigation of the interaction of isopropyl, isobutyl and isoamyl xanthates with silver

The interaction of isopropyl, isobutyl and isoamyl xanthates with silver surfaces has been investigated by voltammetry and by in situ surface enhanced Raman scattering (SERS) spectroscopy. Voltammograms for each homologue are characterised by a prewave occurring at potentials below that at which the silver xanthate compound develops. The prewave was found to shift to more negative potentials by 0.028 V for each additional carbon atom in the alkyl chain between ethyl and isoamyl xanthates. The potassium, sodium and silver xanthates were characterised by Raman and 13C NMR spectroscopies to provide a basis for identifying surface species. The SERS investigations showed that xanthate chemisorbs in the prewave potential region predominantly with the alkyl groups in the all-trans conformation. The xanthates were found to reduce at low potentials.