The adsorption of 2,2 ': 6 ',2 ''-terpyridine, 4 '-(5-mercaptopentyl)2,2 ': 6 ',2 ''-terpyridinyl, and perchlorate on silver and copper surfaces monitored by SERS

摘要

The adsorption of 2,2':6',2"-terpyridine on Ag and Cu electrode surfaces has been studied by using surface enhanced Raman spectroscopy (SERS). Two types of surface complexes have been found on a silver electrode: the first one is stable near the open circuit potential, having bonding between tpy and silver active site analogous to the Ag-N bonding in the [Ag-1(tpy)Cl].2H(2)O complex; and the second one is stable in the -0.1 to -0.5 V (Ag/AgCl) potential range, where the interaction between tpy and silver active site is similar to the Cu-N bonding in the [Cu-II(tpy)Cl-2] complex. The SERS spectra of 4'-(5-mercaptopentyl)-2,2':6',2"-terpyridinyl (tpy-SH) have shown an increase in the relative intensity of the mercaptopentyl moiety bands and a band at 310 cm(-1), assigned to the AgS stretching, indicating an adsorption through the S atom. In addition, using the Raman results of different copper perchlorate salts obtained with different hydration degrees, it has been possible to characterize the adsorption of perchlorate anion on silver electrode and the kind of coordination in the [Cu-II(tpy)(H2O)(ClO4)]ClO4 and [Cu-II(tpy)(H2O)(ClO4)(2)] complexes. (C) 2003 Elsevier Science Ltd. All rights reserved. [References: 35]