  A key to building functional devices on the basis of single molecule magnets
in the framework of molecular electronics is the ability to deposit and study
these molecules on a surface, because the structural, electronic and magnetic
properties of molecules can significantly change upon adsorption. We have used
the submolecular resolution of a scanning tunneling microscope to probe the
local interactions within two different rationally designed
single-molecule-magnet building blocks. A careful analysis of single-molecule
spectroscopic maps reveals that the electronic properties are sensitively
dependent on the molecular structure so that even small changes can drastically
enhance or reduce the intramolecular spin coupling. Due to their planar
geometry, these molecules are ideal model systems to study molecular magnetism
of surface-supported complexes via scanning probe techniques.
