Nuovi chemosensori ottici aventi un derivato benzossazolico come unità sensibile

The development of molecular sensors for the detection of specific targets is a growing area of chemistry. We have synthesized new ligands able to bind metal ions giving a specific fluorescent response to their presence in solution. Following this statement, we have designed four fluorescent chemosensors L1, L2, L3 and L4 including the 2-(2-hydroxy-3-naphthyl)benzoxazole (3), as sensitive fluorescent unit; all chemosensors have been synthesized, characterized and studied for the detection of metal ions in solution. L1 was synthesized linking the 2-(2-hydroxy-3-naphthyl)-4-metylbenzoxazole unit to a pyridyl-thioether macrocycle, the 2,8-dithia-5-aza-[9] 2,6-pyridinophane. L2 is constituted by 2-(2-hydroxy-3-naphthyl)-4-metylbenzoxazole linked to the dimethylamine; L3 shows the same optical active unit linked to the N,N,N’-trimethylethylenediamine and L4 was obtained attaching two (3) units to the two amine functions of the N,N’-dimethylethylenediamine. In all compounds 3 is the signalling units while the amine moieties behave as binding units. Those ligands exhibits zinc and cadmium fluorescence turn-on, according to the deprotonation of 2-(2-hydroxy-3-naphthyl)benzoxazole due to the involvement in the coordination of the metal ion of the group. The capability of the fluorescent response depends in these chemosensors by several factors; among them, the photo electron transfer (PET), leading by lone pairs of linked amines as well as of the fluorescent unit, the twisted intramolecular charge transfer (TICT), due to the conjugation between aromatic rings, are the mains. In the Doctoral Thesis, the synthesis of the chemosensors, the preliminary binding studies towards several metal ions, and the fluorescence response have been reported.