Premium
Competition between adsorption and complexation on silver as monitored by surface‐enhanced Raman scattering
Author(s) -
Pessôa Mônica M. B.,
Temperini Marcia L. A.
Publication year - 2002
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.817
Subject(s) - chemistry , raman scattering , raman spectroscopy , adsorption , semicarbazone , acetonitrile , electrolyte , electrode , analytical chemistry (journal) , electrochemistry , inorganic chemistry , stereochemistry , organic chemistry , physics , optics
Surface‐enhanced Raman scattering (SERS) spectra of 2‐formylpyridine‐4′, 4′‐dimethyl thiosemicarbazone (DMePATS2) on a silver electrode in acetonitrile electrolytic solution were obtained. The effect of Mg(ClO 4 ) 2 on the DMePATS2 adsorption process was investigated. The results show that the configuration of adsorbed DMePATS2 on the silver electrode depends on the applied potential. For negative potentials, the predominant configuration on the surface is E whereas for positive potentials there is almost only the Z isomer. In the presence of Mg 2+ only the ( Z )‐DMePATS2 isomer was observed at any potential, which is explained by the formation of an Mg 2+ –( E )‐DMePATS2 complex in solution. The formation of this complex is also used to explain the decrease in the Raman intensity of the adsorbed species in the time evolution experiment. A comparison is made between the SERS results for DMePATS2 and PATS4 (4‐formylpyridine thiosemicarbazone). The SERS spectra of PATS4 in the presence of Mg 2+ indicate the formation of an Mg 2+ –PATS4 complex on the surface. Copyright © 2002 John Wiley & Sons, Ltd.