Chemisorption of ferrocene on Si(111)–Ag: Frustrated conformational flexibility

The adsorption of ferrocene-dithiol on Si(111)– Ag 3 × 3 reconstruction has been studied by scanning tunneling microscopy. Preferred chemisorption was found at defect sites, e.g. grain boundaries, with characteristic distortions of the two dimensional electron gas. Occasionally, adsorption also occurs at perfect terrace sites, where submolecular resolution was achieved and the adsorption geometry was deduced. Due to the formation of Ag–S bonds, the conformational flexibility of the free ferrocene is restricted. Thus, the frozen rotation leaves only two different rotational configurations of ferrocene.