We report about the electrochemical characterization of redox sites organized at Hg surface by different interactions. Fe(II) and Ru(II) moieties are tethered to the Hg surface via covalent bond being incorporated respectively in the molecules Fe(C5H5)(C5H4)(CH2)4SH and [Ru(NH3)5NC5H4CH2NHCO(CH2)10SH](PF6). The electrochemical characterization indicates that the redox species are located at the external surface of the monolayer. Alternatively, [Ru(NH3)6](PF6)3 species are absorbed to the Hg surface via electrostatic interactions with a negatively charged SAM formed on the Hg surface. In the latter case the SAM is formed by 11-mercaptoundecanoic acid that at pH at pH 5 and 9 exposes carboxylic acid groups. We show that at pH less than 4, when the carboxylic group is fully protonated, CV measurements show negligible current, while at pH higher than 5, the voltammograms show a well-defined redox wave at about −0.21 V vs. Ag/AgCl. A study of the voltammetric responses of the Ru(NH3)63+/2+ couple as a function of electrolyte composition and concentration at pH 9 is reported.
Electrochemical Characterization of Transtion Metal Complexes at Hg Surfaces
CATTABRIGA, Michela;FERRI, Violetta;RAMPI, Maria Anita
2006
Abstract
We report about the electrochemical characterization of redox sites organized at Hg surface by different interactions. Fe(II) and Ru(II) moieties are tethered to the Hg surface via covalent bond being incorporated respectively in the molecules Fe(C5H5)(C5H4)(CH2)4SH and [Ru(NH3)5NC5H4CH2NHCO(CH2)10SH](PF6). The electrochemical characterization indicates that the redox species are located at the external surface of the monolayer. Alternatively, [Ru(NH3)6](PF6)3 species are absorbed to the Hg surface via electrostatic interactions with a negatively charged SAM formed on the Hg surface. In the latter case the SAM is formed by 11-mercaptoundecanoic acid that at pH at pH 5 and 9 exposes carboxylic acid groups. We show that at pH less than 4, when the carboxylic group is fully protonated, CV measurements show negligible current, while at pH higher than 5, the voltammograms show a well-defined redox wave at about −0.21 V vs. Ag/AgCl. A study of the voltammetric responses of the Ru(NH3)63+/2+ couple as a function of electrolyte composition and concentration at pH 9 is reported.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
