On-surface synthesis of ballbot-type N-heterocyclic carbene polymers

N-Heterocyclic carbenes (NHCs) are established ligands for metal complexes and surfaces. Here we go beyond monomeric NHCs and report on the synthesis of NHC polymers on gold surfaces, consisting of ballbot-type repeating units bound to single Au adatoms. We designed, synthesized and deposited precursors containing different halogens on gold surfaces under ultrahigh vacuum. Conformational, electronic and charge transport properties were assessed by combining low-temperature scanning tunneling microscopy, non-contact atomic force microscopy, X-ray photoelectron spectroscopy, first-principles calculations and reactive force field simulations. The confirmed ballbot-type nature of the NHCs explains the high surface mobility of the incommensurate NHC polymers, which is prerequisite for their desired spatial alignment. The delicate balance between mobility and polymerization rate allows essential parameters for controlling polymer directionality to be derived. These polymers open up new opportunities in the fields of nanoelectronics, surface functionalization and catalysis.

Tuning the formation of discrete coordination nanostructures

Novel surface coordination nanostructures based on cyanosexiphenyl molecules are assembled on a gold surface and investigated by scanning tunneling microscopy and density functional theory. Their formation can be tuned by varying the surface temperature during deposition. Diffusing gold adatoms act as coordination centers for the cyano groups present on one end of the nonsymmetrical molecules.

Heat-induced formation of one-dimensional coordination polymers on Au(111): an STM study

Upon annealing, H-bonded nanoribbons are transformed into 1D coordination polymers on Au(111) governed by an unusual threefold coordination bonding motif.

Programmed assembly of 4,2′:6′,4′′-terpyridine derivatives into porous, on-surface networks

4,2′:6′,4′′-Terpyridine building blocks self-assemble into hydrogen-bonded domains; addition of copper atoms results in an on-surface transformation into a coordination network.

Adsorption of a dihydro-TTF derivative on Au(111) via a thiolate complex bonding to gold adatoms

A dihydro-TTF derivative was adsorbed on Au(111) via four thiolate ligands, it is determined that relatively little charge transfer occurs between the molecule and the substrate.