The structure of or­ga­nic compounds on metal surfaces is of great interest for the fabrication of devices in the field of organic elec­tro­nics but for future progress a deeper understanding of intermolecular interactions and charge transfer is required. In cooperation with the research group of Prof. Anke Krüger at Würzburg's Institute for Organic Chemistry we have investigated the two-dimensional self-assembly of tri­ben­zo­triquin­acenes (TBTQs) on Ag(111) by scan­ning tun­neling micros­copy (STM). Highly ordered monolayers were observed for the first time. STM measurements identify a charge transfer between substrate and TBTQ.  The result has been published in  the Jour­nal of Physical Chemistry C. 

Organic chem­istry allows for a basically infinite number of mo­di­fi­ca­tions of molecular struc­tures.  For example, substituents added to a molecule can lead to either a stronger or a weaker coupling to the substrate.  We performed a comparative study of tetra-tert-butyl phthalocyanine (ttbPc) isomers on a Ag(111) surface by means of low-temperature scanning tunneling microscopy to analyze the influence of substituents on the tautomerization, a proton transfer reaction, in single molecules.  By comparison with other well-studied molecules we find a decoupling of ttbPc from the surface.  We find significant differences between the four ttbPc isomers which naturally exist due to different bonding positions of the tert-butyl groups on the macrocycle.  The result has been published in the Journal of Physical Chemistry C.