Towards the engineering of molecular nanostructures: local anchoring and functionalization of porphyrins on model-templates

Abstract

We demonstrate that Cu(111) surfaces pre-covered with a submonolayer of copper oxide or metallic nickel are suitable model-templates for the selective adsorption and/or localized functionalization of functional molecules such as different free base porphyrins and metalloporphyrins. The oxide/Cu(111) model-template is able to steer the adsorption of tetraphenylporphyrins (TPP): 2HTPP selectively adsorbs on the bare Cu areas, and for CoTPP anchoring at the rim of the copper oxide islands is found. On the Ni/Cu(111) model-template TPP molecules are pinned on the Ni areas while they are mobile on the bare Cu surface. Interestingly, adsorption of free base octaethylporphyrin on Ni/Cu(111) leads to a local functionalization, namely the metalation to NiOEP on the Ni areas. Model-template preparation and characterization by scanning tunneling microscopy is performed at room temperature.

Surface chemistry of porphyrins and phthalocyanines

“…Selective adsorption of CoTPP and 2HTPP on Cu-oxide/Cu (1 1 1) and Ni/Cu(1 1 1) was observed by Ditze and coworkers [367]. On a Cu(1 1 1) surface with Cu-oxide islands, both porphyrins preferred adsorption on the bare Cu surface.…”

“…For 2HTPP (see Fig. 3 and Table 1 for the molecular structure), intermolecular repulsion has been observed on Cu(1 1 1) [364][365][366][367][368][369], whereas attractive interactions have been found upon adsorption on Ag (1 1 1 Accordingly, low submonolayer coverages of 2HTPP on Cu(1 1 1) were found to consist of isolated molecules, which were oriented along the high-symmetry directions of the substrate and showed slow diffusion [364,365,368,369,381,382] (cf. Section 4.6.1).…”

Studying the dynamic behaviour of porphyrins as prototype functional molecules by scanning tunnelling microscopy close to room temperature

“…4,32,35,36,56,58,[72][73][74][75][76][77][78][79][80][81][82][83][84][85] It is nowadays well established that metalloporphyrins can be synthesised readily on a metal surface by the reaction of a corresponding free base porphyrin with an ''available'' metal atom. The respective metal atom can be provided on the surface by pre-or postdeposition, or originate from the surface itself.…”

Surface Morphology of Fe(III)-Porphyrin Thin Layers as Characterized by Atomic Force Microscopy

“…Porphyrin supramolecular structures can be formed on metal substrate surfaces as a result of metal-porphyrin and porphyrin-porphyrin interactions [9]. As such, individual molecules can be considered as single nanometer devices [10][11][12]. There have been several fascinating studies of coupling between the porphyrin molecules and the thin layers of substrates [13][14][15][16][17].…”