A voltammetric study of 6-mercaptopurine monolayers on polycrystalline gold electrodes |
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Authors: | R Madueño JM Sevilla T Pineda AJ Román M Blázquez |
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Institution: | Departamento de Qu??mica F??sica y Termodinámica Aplicada, Universidad de Córdoba, Campus de Rabanales, C-3, E-14071 Cordoba, Spain |
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Abstract: | 6-Mercaptopurine (6MP) monolayers were formed spontaneously on different gold surfaces by chemisorption from 6MP solutions. The present cyclic voltammetric study reveals that the monolayer formed is stable in a wide potential range up to values where the oxidative desorption occurs. The reductive desorption of 6MP at a polyfaceted gold electrode shows a multi-wave response. This has been analysed by comparing the observed peak potentials with those obtained at low-index single crystal gold electrodes. The film has no apparent effect on the electron transfer rate constant of Ru(NH3)63+/2+ and Fe(CN)63?/4? at the substrates studied, but modifies the electron transfer rate of the benzoquinone redox couple. This behaviour is typical of thin films where only the slower reactions should display a larger apparent decrease of the rate constant. In contrast, the 6MP-monolayer shows a strong ability to inhibit electroreduction of dioxygen at polyfaceted gold while it remains stable. |
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Keywords: | 6-Mercaptopurine Self-assembled monolayers Polycrystalline gold disk electrode Polyfaceted gold bead electrode Reductive desorption Cyclic voltammetry |
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