2026-05-31T22:23:08Zhttps://riuma.uma.es/rest/oai/request

oai:riuma.uma.es:10630/283442026-02-03T11:28:17Zcom_10630_2254col_10630_37953

00925njm 22002777a 4500 dc López-Ramírez, María Rosa author Aranda, Daniel author López-Tocón, Isabel author Soto-Martín, Juan author Castro, José Luis author Otero-Fernández-de-Molina, Juan Carlos author 2020-10-08 Surface-enhanced Raman scattering of thiobenzoic acid and thiobenzamide have been recorded on three different silver colloids in order to find the chemical species responsible for the spectra and to detect differences in the adsorption with respect to their oxygen counterparts, benzoic acid and benzamide, respectively. Very significant and unexpected shifts of opposite sign between the Raman and SERS wavenumbers have been detected. By comparing the experimental and DFT calculated wavenumbers, it can be concluded that the acid is bonded to the metal as thiobenzoate through the sulfur atom with unidentate coordination. SERS spectra of thiobenzamide can be explained by assuming that it is adsorbed as azanion, like in the case of benzamide, linking to the metal through the sulfur and nitrogen atoms of the ionized thiocarboxamide group. In order to support these conclusions, B3LYP/LanL2DZ force field calculations for different complexes of silver cations with the thiobenzoate anion, the neutral thiobenzamide as well as its azanion have been carried out. Additionally, the 8a;nring mode is the most enhanced band in the SERS of both adsorbates pointing to the participation of a metal-to-molecule resonant charge transfer mechanism. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 246 (2021) 119048 https://hdl.handle.net/10630/28344 10.1016/j.saa.2020.119048 Efecto Raman de superficie intensificada Adsorción Differentiated adsorption of thiobenzoic acid and thiobenzamide on silver nanoparticles determined by SERS spectroscopy.