Photoinduced processes in self-assembled porphyrin arrays

Non-covalently assembled supramolecular structures are of great interest in the mimicking of photosynthetic reaction centers and light-harvesting antenna complexes. Bis-Zn(II) porphyrins systems where an organic spacer connects two zinc porphyrin moieties in a V-shaped geometry have been employed for the construction of stable non-covalent and photoactive assembly by means of multiple Zn(II)-nitrogen interactions. We here report on the complexation of bis-zinc porphyrinic tweezers with a tetrapyridyl free-base porphyrin guest. The experiments evidenced the formation of a 2:1 (bis-zinc tweezers/free-base porphyrin) host-guest complex. The photophysical characterization of the complex and of its components will be presented: we observe a quenching of the luminescence of the Zn-porphyrin guest and an unusual quenching of the luminescence of the free-base porphyrin host when engaged in the complex.