Fullerene-Terminated Alkanethiolate SAMs on Gold Generated from Unsymmetrical Disulfides

We report the generation of new multicomponent self-assembled monolayers (SAMs) from the adsorption of unsymmetrical disulfides R(CH2)4SS(CH2)6NC60 (where R = CH3CH2− or CH3O− and C60 = Buckminsterfullerene) onto the surface of gold. These new SAMs expose a high coverage of fullerene moieties as judged by ellipsometric thickness, contact angle measurements, and imaging with a scanning tunneling microscope (STM). The contact angle measurements suggest a more robust coverage than fullerene-terminated SAMs generated from other approaches. Furthermore, the STM measurements represent, to our knowledge, the first direct molecular-scale images of fullerene moieties attached to the surface of a SAM.