Collect. Czech. Chem. Commun. 1991, 56, 750-759

Interfacial bahaviour of indolecarboxylic acids and structural parameters

Luca Benedetti*, Claudio Fontanesi, Giulio Camurri and Giovanna Battistuzzi Gavioli

Department of Chemistry, University of Modena, via Campi 183, 41100 Modena, Italy


The adsorption at the mercury/aqueous solution interface of the 3-, 4-, 5-indolecarboxylic acids in their anionic form has been characterized. The thermodynamic analysis has shown that the process is mainly determined by the interaction of the planar aromatic system with the mercury surface and well described by a Frumkin type isotherm. From the experimental values of the electrosorption valency (γN) and using the model proposed by Schultze a relation between the partial charge transfer (λ) and the repulsive Frumkin interaction parameter has been found. At least, the interfacial activity of the aromatic anions is also discussed on the basis of localized (charge densities) and delocalized (frontier MO energies) theoretical parameters.