Functional dipyrrins for a multi- purpose task: chemical sensing and energy transfer investigations

The synthesis of multifunctional p-electron systems with specific photophysical properties represents a goal for researchers both in synthetic chemistry and materials science. In this framework, opportunely functionalized chromophores like porphyrins or bodipys can be considered high versatile tools for multifunctional applications such as artificial light harvesting supramolecular architectures or as chemical sensors for the detection of contaminants in solution. Despite many reports dealing with the use of porphyrin or bodipy systems, their subunits such as dipyrrin are only rarely used for photometric metal detection. Indeed, these classes of molecules due to their photophysical properties and for their high coordination constants with metal ions and then their optical feedback upon coordination, are excellent candidate for achieving new fast, cheap and sensitive chemical sensors. Based on these considerations, recently we focused our attention on the synthesis of new molecules opportunely functionalized with uracil and/or the acetylated diamino pyridine moieties for detection of contaminant such as melamine and/or metal ions in solution. The spectroscopic investigation has been carried out using a combination of UV/Vis absorption, static and time- resolved fluorescence, and 1H- NMR. Furthermore, in the case of bodipy molecules, the presence of the two complementary groups able to interact by hydrogen bonding allow the formation of an heterodimer that could be an interesting system to investigate the role and the mechanism of long- lived quantum coherence phenomenon in electronic energy transfer (EET) in artificial photosynthetic light harvesting systems (LHs).