Anchoring of Organic Molecules to a Metal Surface: HtBDC on Cu(110)

Abstract

The interaction of largish molecules with metal surfaces has been studied by combining the imaging and manipulation capabilities of the scanning tunneling microscope (STM). At the atomic scale, the STM results directly reveal that the adsorption of a largish organic molecule can induce a restructuring of a metal surface underneath. This restructuring anchors the molecules on the substrate and is the driving force for a self-assembly process of the molecules into characteristic molecular double rows.

Self-assembly of Rubrene on Copper Surfaces

“…We do not observe isolated molecules outside of the molecular ensembles, which is further evidence that any molecules not contained in the structured islands are highly diffusive. 60,61 Islands are observed after a threshold coverage of approximately 0.7 monolayers (ML) is reached. Similar behavior has been observed for other π-conjugated hydrocarbons on other metallic surfaces, for example, perylene on Ag(110) 62 and Cu(100), 56 coronene on Cu(100), 63 and complex helical molecules such as heptahelicene on Cu(111).…”

Bicomponent Supramolecular Architectures at the Vacuum–Solid Interface

“…(110) surfaces create a characteristic trench under the molecule in which 14 Cu atoms are removed from the surface layer in two neighboring close-packed rows. 256 Similarly, the adsorption of a Lander molecule on Cu(211) leads to a reconstruction of the surface (311) steps. This effect of surface reconstruction induced by molecular adsorption was also observed at the step edge of a…”

Heterogeneous Enantioselective Hydrogenation over Cinchona Alkaloid Modified Platinum: Mechanistic Insights into a Complex Reaction

“…Adsorption of the prochiral reactant on the two enantiofaces is unequal, which is assumed to be the origin of enantiodifferentiation. Such a "template model" is improbable for the Pt-cinchona alkaloid system due to the following reasons: Ordered overlayers of cinchona alkaloids or related compounds have not been found on 18 (b) selective adsorption of a chiral molecule on chiral sites of one handedness (blocking) on a racemic surface of a metal particle; (c) creation of chiral sites on nonchiral terraces through adsorption induced reconstruction 21 (the example shows STM images of adsorbed 2,5,8,11,14,17-hexa(tert-butyl)decacyclene (HtBDC, C 60 H 66 ) on Cu(110) (top), which results in the creation of chiral kink sites (bottom); even without reconstruction the adsorption of a chiral molecule may lead to a "chiral footprint"); 22 (d) supramolecular chirality on nonchiral terraces by self-assembly of chiral molecules (the example shows adsorbed tartaric acid on Cu(110); 27 the adsorption pattern destroys all symmetry planes of the underlying metal surface; such adsorption patterns may leave shaped assemblies of surface atoms free (template)); 28 (e) a chiral site on a metal surface can be generated by adsorption of a chiral molecule (modifier).…”

“…This was demonstrated by scanning tunneling microscopy (STM) for adsorption of 2,5,8,11,14,17-hexa(tert-butyl)decacyclene (HtBDC, C 60 H 66 ) on Cu(110). 21 The driving force for such a process is the larger adsorption energy of the molecule on the reconstructed surface with respect to adsorption on the nonreconstructed surface, which overcompensates the energy for reconstruction. A net driving force is therefore only expected for large molecules with big adsorption energy.…”