Supramolecular assemblies of a bis(terpyridine) ligand and of its [2x2] grid-type Zn(II) and Co(II) complexes on highly ordered pyrolytic graphite.

The synthesis and characterisation of bis(terpyridine)-derived ligands which are capable of forming [2x2] grid-like complexes is presented. Additional pyridine substituents on these ligands do not interfere with the complexation process. Adsorbing one of the pure ligands on highly ordered pyrolytic graphite (HOPG) shows a highly ordered structure stabilised by additional weak intermolecular C-H...N hydrogen bonds partially through the extra-pyridines as could be shown by scanning tunneling microscopy (STM) investigations. Similar adsorption experiments with one of the corresponding [2x2] Co(II) grid-type complexes on graphite, led also to a well-organised structure with interdigitation of the extra-pyridine moieties.