Reinventing Dihydrophenazine Systems: From Smart Materials To Catalysis

DIPC Seminars

Jacopo Dosso
Università degli studi di Trieste
Donostia International Physics Center (In person seminar)
Abel de Cózar
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Reinventing Dihydrophenazine Systems: From Smart Materials To Catalysis

The synthesis and characterization of systems presenting multiple properties that can be changed by modifying a single parameter, eg. the oxidation state, is of high interest in today’s science. This arises from the fact that such molecules can be integrated into multifunctional materials that can perform different tasks depending on the state of the active component. From this point of view, dihydrophenazines are highly valuable derivatives since they present an interesting redox chemistry in which a radical cation and a closed shell aromatic dication can be formed reversibly by consecutive single electron oxidations, resulting in dramatic changes in optoelectronic properties. Until now, the studies reported in the literature concern mostly the radical cationic systems due to their persistent nature, while the dications have been investigated only marginally due to their marked reactivity arising from prominent coulombic repulsion. In a recent work, our group effectively demonstrated how an interplay of aromaticity and p-extension is essential in achieving accessible dicationic states. This led to the first extensive characterization of these derivatives highlighting molecular switching capabilities and electrochromism along with an intriguing reactivity. At the same time, functionalization of the extended dihydrophenazine systems resulted in their inclusion in polymeric materials, which present a high surface area that can be effectively modified by the oxidation of the material to the dicationic state, suggesting that extended dihydrophenazines can be used to generate multifunctional materials. Finally, functionalzied p-extended dihydrophenazines have also been exploited successfully as organophotocatalysts, leading to activation of challenging aryl halides. This result opens a new pathway for the exploitation of extended dihydrophenazines as electron rich photocatalysts.