Solvent Effects on the Adsorption and Self-Organization of Mn12 on Au(111)

A sulfur-containing single molecule magnet, [Mn12O12(O2CC6H4SCH3)16(H2O)4], was assembled from solution ona Au(111) surface affording both submonolayer and monolayer coverages. The adsorbate morphology and the degreeof coverage were inspected by scanning tunneling microscopy (STM), while X-ray photoelectron spectroscopy (XPS)allowed the determination of the chemical nature of the adsorbate on a qualitative and quantitative basis. The propertiesof the adsorbates were found to be strongly dependent on the solvent used to dissolve the magnetic complex. Inparticular, systems prepared from tetrahydrofuran solutions gave arrays of isolated and partially ordered clusters onthe gold substrate, while samples prepared from dichloromethane exhibited a homogeneous monolayer coverage ofthe whole Au(111) surface. These findings are relevant to the optimization of magnetic addressing of single moleculemagnets on surfaces.