Investigation of the structure of self-assembled monolayers of asymmetrical disulfides on Au(111) electrodes by electrochemical desorption

In this paper the reductive desorption for homogeneously mixed self-assembl ed monolayers (SAMs) on Au(lll) electrodes formed from an asymmetrical disu lfide, i.e. butyl hexadecyl disulfide [C4H9-S-S-C16H33; H4H16] or decyl 2-( perifluorohexyl)ethyl disulfide [C10H21-S-S-(CH2)(2)(CF)(5)CF3; H10F8] was studied by cyclic voltammetry. Peak potentials of electrochemical desorptio n waves for the SAMs of these asymmetrical disulfides were different from t hose of SAMs containing only one of the constituent chains. The peak potent ial deviation from those of the single component SAMs suggests mixing of th e two constituent chains in molecular dimensions. The ratio of the two cons tituent chains of the asymmetrical disulfide in each of the SAMs was consid ered to be exactly 1:1 when the homogeneously mixed SAMs were prepared unde r favorable conditions with respect to reaction concentration and temperatu re. We will discuss features of cyclic voltammograms in terms of the struct ure of the SAMs. (C) 1999 Elsevier Science S.A. All rights reserved.