Synthesis of polycyclic aromatic hydrocarbons and graphite islands via surface-induced reaction of small molecules.

Attractive materials for molecular electronics are the polycyclic aromatic hydrocarbons (PAHs), the hydrogen-terminated segments of a graphitic plane. Since the processing of larger PAHs, for example hexa-peri-hexabenzocoronene, is complicated by their extremely low solubilities and very small vapor pressures, the possibility of a surface-assisted synthesis of planar PAHs is investigated starting from diphenylacetylene (left) and hexaphenylbenzene (right), as shown in the picture.

Template-Mediated Synthesis of Polycyclic Aromatic Hydrocarbons: Cyclodehydrogenation and Planarization of a Hexaphenylbenzene Derivative at a Copper Surface.

The deposition of polycyclic aromatic hydrocarbons on substrate surfaces is a key step for using such disklike molecules in nanoelectronic devices. An alternative to the (frequently problematic) preparation by evaporation or deposition from solution is to use the substrate surface as a template for the planarization that accompanies the cyclodehydrogenation (see picture).