Evidence for Nondestructive Adsorption of Dialkyl Sulfides on Gold

The nondestructive adsorption of long chain dialkyl sulfides on gold is reported. Self-assembled monolayers of decanethiol, didecyl disulfide, and didecyl sulfide were prepared and characterized by XPS, grazing-angle FT-IR, wettability studies, and TOF-SIMS. The first three techniques provide evidence that well-packed monolayers are formed. The positive SIMS spectrum of didecyl sulfide showed fragments that originate from intact dialkyl sulfide attached to gold without C−S bond cleavage. Our results underline the generally accepted nondestructive adsorption process of dialkyl sulfides and contradict the recently reported cleavage of one of the alkyl sulfur bonds of sulfides upon adsorption.