In recent years, the attempts to build artificial functional devices from single molecules were strongly in the focus of surface nanoscience. The majority of the created systems resulted in large thermodynamic ensembles supported within fluids or the 3D bulk. Nevertheless, for technological applications, a simple way to produce vast amounts of supramolecular devices in an ordered and easily accessible structure like a two-dimensional lattice is needed.
Herein we report on a highly complex supramolecular device that reminds of a mechanical rotary switch fabricated on a Cu(111) surface following the "bottom-up" approach. Self-assembly of a specially functionalized porphyrin molecule leads to the formation of a porous network featuring chiral cavities which serve as hosts for molecular guests. These can rotate between six stable positions of which three are distinguishable by Scanning Tunneling Microscopy (STM). The rotation can be induced either thermally or by the STM tip. The energy barrier for rotation was estimated to be 0.24 eV.