| Abstract
| - The adsorption of 5-(octyldithio)-2-nitrobenzoic (O-DTNB) onto gold electrode surfaces has beeninvestigated with a quartz crystal microbalance, and the process appears to follow the Freundlich adsorptionmodel. Atomic force microscopy images of adsorbed films obtained from 20 μM and 10.0 mM ethanolicsolutions of O-DTNB exhibited dramatically different morphologies which were ascribed to the formationof multilayer equivalent aggregates. Similar to adsorbed films derived from 5,5‘-dithiobis(2-nitrobenzoicacid) (DTNB), cycling the potential past −0.55 V for adsorbed films of O-DTNB resulted in the generationof a reversible, pH-dependent, redox couple ascribed to formation of the hydroxylamine from the nitrogroup. For films obtained from a high concentration (10.0 mM) of O-DTNB, generation of the reversibleredox couple did not appear to result in desorption of the additional adsorbed material as ascertained fromEQCM data. The cyclic voltammetric profiles of [Fe(CN)6]3-, hydroxymethylferrocene, and [Co(phen)3]2+at gold electrodes modified with O-DTNB was pH dependent, and this behavior was ascribed to the acid/base behavior of the carboxylic acid substituent.
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