Network of Tris(porphyrinato)cerium(III) Arranged on the Herringbone Structure of an Au(111) Surface

A network of bithiophene-modified tris(porphyrinato)cerium(III) triple-decker (TD) complexes was formed by pulse injection depositing oil the Au(111) surface. The structure was observed with ultrahigh vacuum scanning tunneling microscopy(UHV-STM). High resolution UHV-STM images revealed the details of network structure of TD and the internal structure of both bithiophene and porphyrin moieties, indicating that the TD complexes undergo face-on adsorption. The alkyl chains on these bithiophenes not only make the TD molecules soluble in organic solvents, but also play it key role in preventing them front forming bonds between the thiophenes and the Au substrate, which enables the porphyrin molecular surface to be perpendicular to the substrate. These results suggest that the thiophene moiety can be used to control the adsorption and assembly of molecules on the herringbone structure of the Au(111) surface.