Synthesis and use of new Porphyrin Derivatives

The Ph.D work was aimed to design, synthesize, and test capabilities of new spermine-porphyrin and BODIPY derivatives, and to study their interactions with various biological targets. The research period was focused on the synthesis of porphyrin derivatives with a different number of spermine pendants, in order to combine the hydrophobic and hydrophilic behaviour in a single molecule with the possibility to modulate the two properties, but meanwhile also to have biocompatible features. In particular, polyamine arms make these compounds quite soluble in aqueous solution and let them to interact with the anionic backbones of different DNA structures, displaying a different protonation degree depending on pH. The results obtained by CD-measurements, UV-Vis, fluorescence and RLS spectroscopy support the good ability of these derivatives (i.e. ZnTCPPSpm4) to act like inducer, probe and stabilizer towards the Z-form of DNA. Moreover, they show a good affinity with G-Quadruplex (i.e. H2TCPPSpm4) opening the way to several supramolecular structures. In addition, these porphyrins are able to self-assembly under hierarchical control, obtaining the desired aggregation state in solution, by choosing the appropriate pH value. The collected results do not allow to propose a definitive mechanism of interactions between porphyrin-porphyrin, and porphyrin-DNA and therefore further work is in progress in order to get a rationale which can help in designing ad hoc molecules to selectively interact with the target biomolecules.