Calculated and structural analyses of self-assembly formed by [7]thiaheterohelicene-2,13-carboxaldehyde molecules on Au(111).

Recently, the electronic and structural properties of large self-assembled domains of [7]thiaheterohelicene-2,13-carboxaldehyde helicene ([7]TH-dial) molecules on Au(111), Cu(001), and NiAl(110) metal surfaces have been characterized by scanning tunneling microscopy (STM). Several distinct areas of the self-assembled structures can be observed. To describe and explore the morphology of and the interactions in these distinct self-assembled nanostructures, we combine the results obtained through calculations in a semi-empirical framework and calculated STM images.

Self-Assembly of Molecular Landers Equipped with Functional Moieties on the Surface: A Mini Review.

The bottom-up fabrication of supramolecular and self-assembly on various substrates has become an extremely relevant goal to achieve prospects in the development of nanodevices for electronic circuitry or sensors. One of the branches of this field is the self-assembly of functional molecular components driven through non-covalent interactions on the surfaces, such as van der Waals (vdW) interactions, hydrogen bonding (HB), electrostatic interactions, etc., allowing the controlled design of nanostructures that can satisfy the requirements of nanoengineering concepts.

Unraveling the molecular conformations of a single ruthenium complex adsorbed on the Ag(111) surface by calculations.

The tris(dibenzoylmethanato)ruthenium (Ru(dbm)3) molecule has recently been characterized by scanning tunneling microscopy (STM) experiments upon adsorption on Ag(111). The adsorbed Ru(dbm)3 molecule shows two conformations with respect to the [11[combining macron]0] direction of the substrate, one with a three-lobed feature and the other one with a bi-lobed structure. For each of these structures, the molecule can take two geometries (states).

Three-dimensional hydrogen bonding between Landers and planar molecules facilitated by electrostatic interactions with Ni adatoms.

Using a combination of UHV-STM and molecular mechanics calculations, we investigate the surface self-assembly of a complex multi-component metal-molecule system with synergistic non-covalent interactions. Hydrogen bonding between three-dimensional Lander-DAT molecules and planar PTCDI molecules, adsorbed closer to the surface, is found to be facilitated by electrostatic interactions between co-adsorbed Ni adatoms and the flexible molecular DAT groups.

Observation and manipulation of hexa-adamantyl-hexa-benzocoronene molecules by low temperature scanning tunneling microscopy.

Large molecules made of a central hexa-adamantyl-hexa-benzocoronene plateau surrounded by six adamantyl groups have been investigated by low temperature scanning tunneling microscopy and scanning tunneling spectroscopy coupled with image calculations and molecular mechanics. The structure of large self-assembled domains reveals that the intermolecular interactions between adamantyl peripheral groups dominate film growth. At very low coverage, the molecules can exhibit a certain instability for negative bias voltages which induces a partial rotation.

Self-assembly of hydrogen-bonded chains of molecular landers.

One-dimensional chains of a specially designed lander molecule with di-carboxyl imide functional moieties, enabling complementary intermolecular hydrogen bonding, have been self-assembled under ultra high vacuum conditions on a Au(111) surface and characterized by scanning tunneling microscopy.

Supramolecular architectures on surfaces formed through hydrogen bonding optimized in three dimensions.

Supramolecular self-assembly on surfaces, guided by hydrogen bonding interactions, has been widely studied, most often involving planar compounds confined directly onto surfaces in a planar two-dimensional (2-D) geometry and equipped with structurally rigid chemical functionalities to direct the self-assembly. In contrast, so-called molecular Landers are a class of compounds that exhibit a pronounced three-dimensional (3-D) structure once adsorbed on surfaces, arising from a molecular backboard equipped with bulky groups which act as spacer legs. Here we demonstrate the first examples of extended, hydrogen-bonded surface architectures formed from molecular Landers.