Reactivity of 1,8-octanedithiol monolayers on Au(1 1 1): Experimental and

M.L. CAROT; M.J. ESPLANDIU; F.P. COMETTO; E.M. PATRITO; V.A. MACAGNO

JOURNAL OF ELECTROANALYTICAL CHEMISTRY

Elsevier

Año: 2005 vol. 579 p. 13 - 13

0022-0728

p>The reactivity of 1,8-octanedithiol/Au(1 1 1) self-assembled monolayers (SAMs) formed by the immersion method was investigated by means of cyclic voltammetry (CV), scanning tunneling microscopy (STM), electrochemical impedance spectroscopy (EIS) and quantum mechanical calculations. The potential of the reductive desorption process for the dithiol is 99 mV more negative than for 1-octanethiol indicating a higher stability of dithiol monolayers. A reduction charge of −109 ìC/cm2 was obtained for the dithiol which is to be compared to the reductive desorption charge of −83 ìC/cm2 for the monothiol. The extra reduction charge of the dithiol was attributed to the presence of intralayer disulfide bonds at the SAM/electrolyte interface. EIS measurements confirmed that these intralayer linkages increase the stability of the monolayer with respect to the homologue 1-octanethiol/Au(1 1 1). The onset of the reductive desorpti