Selective Assembly of Porphyrin Molecules into Supramolecular Aggregates on a Surface.

Abstract

The rational construction of desired molecular nanostructures should be required to realize molecular nanodevices, ideally with these structures supported on suitable substrates. We report the formation of surface-supported supramolecular structures whose size and aggregations patterns are rationally controlled by using selective and directional intermolecular interactions between cyanophenyl substituents. Using low-temperature scanning tunneling microscopy and molecular orbital calculations, we have analyzed the conformation and arrangement of adsorbed porphyrin molecules on Au(111) surface. In case of cyanophenyl-substituted porphyrins, monomers, trimers, tetramers, or extended wire-like structures is selectively formed on the Au(111) surface by modifying substituents. These structures should be induced by local dipole-dipole interaction between cyanophenyl substituents. Our findings indicate that the rational design and construction of surface-supported supramolecular architectures will be allowed by introducing non-covalent interactions.