SERS studies of the adsorption of 1‐phenyl‐5‐mercaptotetrazole on silver sols

Abstract

AbstractSurface‐enhanced Raman scattering spectra of 1‐phenyl‐5‐mercaptotetrazole (PMT) and of the corresponding sodium salt adsorbed on silver sols were recorded in the 3700–2800 and 1800–150 cm−1 regions. The SERS spectra obtained in both cases are the same, therefore it can be deduced that PMT adsorbs on silver sol in the ionized thiol form (PMTA). Moreover, the similarity between SERS and normal Raman spectra of the corresponding silver complex (AgPMTA) is diagnostic of chemisorption of the substance on the silver surface. SERS data were interpreted with the help of the results of DFT calculations on PMTA and AgPMTA. On the basis of the description provided by the potential energy distribution of the vibrational normal modes related to the most enhanced bands in the SERS spectra, it can be deduced that PMTA interacts with the silver sol via the lone pairs of the sulphur and of one of the nitrogen atoms. The orientation of the tetrazole ring is nearly edge‐on with respect to the metal surface, whereas the molecular plane of benzene ring is inclined to it. Copyright © 2002 John Wiley & Sons, Ltd.