THE HETEROARYLETHENES: SYNTHESIS, ELECTROCHEMISTRY AND INVESTIGATION ON THE AGGREGATION-INDUCED EMISSION OF A PROMISING CLASS OF MOLECULES WITH LUMINESCENT PROPERTIES

The present research has been aimed on the synthesis and to the electrochemical and photophysical investigation of the HeteroArylEthene class constituted by the DiThienylEthene DTE, TriThienylEthene TrTE, TetraThienylEthene TTE, DiFurylEthene DFE, TriFurylEthene TrFE and TetraFurylEthene TFE. The study includes as a benchmark the analogous phenyl-based series which was already well known concerning the synthesis the photophysical properties and the applications. A very limited knowledge was so far available concerning the heteroaryl-based ethenes. Among the investigated systems, TFE and TrTE are entirely new compounds and have been never investigated before; the other structures had already been reported in literature but only obtained by McMurry coupling, while in this work we have proposed a convenient alternative approach (besides significantly improving the McMurry protocol). Moreover, a deep electrochemical and photophysical characterization was still lacking; as a consequence, the highly interesting electrochemical and photoluminescence properties remained concealed until the study performed in this PhD research work, by which interesting features have been unearthed. In particular the investigate molecules have shown efficient π-conjugation emission and electropolymerization ability and the excellent property of the luminescence in solid state. So besides performing a detailed electrochemical investigation of the synthesized family members in terms of redox properties and electrooligomerization ability, we particularly concentrated on their photophysical investigation in terms of Aggregation-Induced Emission features. The latter has been performed in a seven-month stage at the Hong Kong University of Science and Technology, in the laboratories of Professor Ben Zhong Tang, the discoverer of the AIE phenomenon. The results obtained are of high interest and applicative potential. Thus systematic study performed in this thesis now provides a deep knowledge about the heteroarylethene properties which can allow to properly design more complex systems in which these scaffold could be used as starting block. In addition, their unique property of emitting light in solid but not in solution, renders them even more appealing, as small single molecule to be employed in hi-tech applications.