Sintesi di complessi poliossometallati ibridi e multifunzionali

Polyoxometalates (POMs) are discrete polyanionic oxides that shows a wide variety of applications in material science, nanomedicine and catalysis. This thesis describes the synthesis and characterization of a small library of novel polyoxometalate-based hybrids, and includes the preliminary investigations about their possible applications. The preparation of the complexes was obtained through the bis-functionalization of the divacant Keggin polyanion [γ-SiW10O36]8-, which was selected as a model compound for its reproducible synthesis and stability. The decoration of this POM was obtained in one or two steps, and involved the reaction of trialkoxy organosilanes or organo phosphonic acids with the reactive oxygen atoms of the POM vacancy. The POM was thus decorated with the following pendants: -luminescent units (dansyl, pyrene, fluoresceine), to obtain POMs with sensing capabilities in the presence of ions (Cu2+) or apolar molecules (C60), as well as with promising applications in fluorescence imaging, for cell trafficking studies. -bioactive molecules (avidin, folic acid, tryptophan), to be used for the recognition of small molecules or biological targets, with potential application in oxidation catalysis and medicine. In all cases, the successful functionalization was confirmed by means of proton, carbon and heteronuclear NMR (P, Si, W), and ESI-MS and FTIR. The spectral features of the molecular hybrids, and the interactions between the POMs and target molecules/ions were highlighted by fluorescence and UV-Vis spectroscopy. Chiral derivative were also studied by circular dichroism.