Reactions on surfaces for the creation of stable templates

Molecular assemblies on surfaces can be used as templates that allow the study of host guest interactions and thus provide a starting point for the generation of complex hierarchic structures. An important prerequisite besides the regularity of such structures is their stability. We reported the formation of a molecular network generated by thermal dehydrogenation of a perylene derivative (DPDI) on a Cu(111) surface [1]. By thermal activation, these molecules become autocomplementary H-bond donors/acceptors and form a honeycomb structure. Besides utilizing this network for the incorporation of guest molecules [2], NIXSW (normal incidence x-ray standing wave) experiments were carried out to determine the height of DPDI above the substrate surface before and after the thermal activation. The formation of the network involves a lowering of the height difference between the molecular end groups and the perylene core what is required to enable H-bonding between the molecules. [1] M. St\"{o}hr et al., Angew. Chem. Int. Ed., 44 (2005) 7394; [2] M. St\"{o}hr et al., Small 3 (2007) 1336