Photoinduced processes in self-assembled supramolecular complexes based on porphyrins

The self-assembly of multi pyridyl ligands with Zn(II) porphyrin architectures is a well known strategy to obtain highly stable non-covalent supramolecular complexes. These structures, when containing porphyrins and other photoactive or electroactive units, represent an important challenge in relation to the mimicry of bacterial photosynthesis and for applications in molecular electronics and photonics. Here we report on some recently explored examples of this type of complexes, in particular cages formed by the self-assembly of Zn-trisporphyrin platforms by axial coordination with dipyridyl free-base porphyrins or dipyridyl perylene bisimides (Figure 1a) and a pentaporphyrinic array formed by the coordination of two Zn-bisporphyrin clips with a central free-base porphyrin (Figure 1b). The binding equlibria have been characterized by means of UV-Vis or 1H NMR titrations and photophysical investigations have been carried out in conditions where the fully assembled complex is the major species. All the examined supramolecular structures present interesting photoinduced activity such as energy or electron transfer processes.1-3