Gold Surfaces have been modified by self-assembled techniques. Here the adsorption time of diasteroisomers (1R, 3S)-1-ferrocenyl-3-methyl4,4-diphenyl-2,5-dioxacyclopentane and (1S, 3S)-1-ferrocenyl-3-methyl-4,4-diphenyl-2,5-dioxacyclopentane (Scheme 1, (3a) under bar and (3b) under bar) at a An surface in ethanol solution was controlled. This study was followed by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) analysis. The method used for the surface modification was the control of exposure time of a An surface in the modifier/ethanol solution. It was demonstrated by EIS and XPS that the An surface was modified with mixture of compounds (3a) under bar + (3b) under bar, avoiding the electron transference in the interface. It was also observed that the organometallic molecule indeed had been adsorbed on the Au surface. In addition, evidence seems to conclude that the molecule-Au interaction is through the electrons of cyclopentadienyl moiety, where the oxygen atoms are near the air-molecule interface and the iron atom is near the An surface. This type of interaction of the ferrocene derivatives with gold surfaces has not been reported by any other author. Published by Elsevier B.V.