Tailoring supramolecular assemblies on a metal surface by specifically functionalized porphyrins

The self-assembly behavior of porphyrin derivatives bearing di�erent substituents
is investigated on metal surfaces by Scanning Tunneling Microscopy
(STM). Di�erent methods to control the self-assembly process by skillful
changes of the molecular substituents are developed. It is shown how onedimensional
wires as well as two-dimensional nanoporous networks can be
formed by the same molecular compound depending on the coverage. The
nanoporous networks can be altered in their pore characteristics and poreto-
pore distances in a controlled way. This is exploited to form a fully selfassembled
supramolecular device. The characteristics of the device are studied
in detail and it is shown that it can be operated by the tip of an STM.
Finally, bimolecular systems are investigated. Here it is shown how the need
to balance losses of entropy which is a common factor in all self-assembled
networks, can be exploited to direct the self-assembly of such systems to form
either separated phases or an intermixed network.