Ft-SERS studies on 1,3-thiazolidine-2-thione, 2,5-dimercapto-1,3,4-thiadiazole and 2-thiouracil adsorbed on chemically deposited silver films

Adsorption of 1,3-thiazolidine-2-thione (ttz), 2,5-dimercapto-1,3,4-thiadiazole (dmtd) and 2-thiouracil on a silver surface was studied by the FT-SERS technique. The FT-SERS spectra of all these molecules indicate dissociative adsorption on the silver surface to the corresponding thiolate ion. For ttz and 2-thiouracil, the corresponding thiolate ions are found to adsorb to the surface through their sulfur atoms and have a perpendicular orientation on the silver surface. For dmtd, the results suggest that the dithiolate ion has two kinds of adsorption geometries depending on the concentration of the dmtd in solution. At low concentration the diothiolate ion probably adsorbs through the nitrogen atom whereas at high concentration the ion probably adsorbs through its pi -system Copyright (C) 2001 John Wiley & Sons, Ltd.