Abstract
In recent years, photoinduced chemical transformations have received great attention, providing several new opportunities to organic synthesis, within a green chemistry perspective. Electrophotocatalysis (EPC) is one of the most promising technological innovation in this field, as a successful synergic combination of homogenous photocatalysis (PC) and electrochemistry (EC). By employing clean energy (light and electricity derived from renewable sources) and by coupling photo and electrochemical steps within the same catalytic cycle, EPC is able to promote chemical reactions under milder conditions, increasing selectivity, without the use of sacrificial reagents or activating functional groups, lowering the environmental impact of chemical synthesis. Moreover, EPC is able to generate catalysts with excited-state redox potentials beyond those accessible via PC alone, or it allows lowering the applied potentials of conventional EC. Anyway, EPC is still at its infancy and only few organic dyes and a couple of archetypical transition-metal complexes have been tested as catalysts in unoptimized organic reactions. Indeed, the development of new catalysts specifically engineered for electrophotocatalytic applications is not yet reported and the use of transition-metal complexes, while pervasive in PC, is basically unexplored in EPC. HEPIrCOS will take advantage of the expertise of the project team to (i) computationally engineered cyclometalated iridium(III) complexes for EPC applications, (ii) fully characterize them, and (iii) test them in challenging organic reactions, as well as in key synthetic steps of industrial or pharmaceutical relevance. Iridium-based EPC can take advantage of the remarkable thermal, photoand electro-chemical stability of such complexes and of the highly tunable energy levels, that can be modulated with simple modifications on the cyclometalating or ancillary ligands. Furthermore, HEPIrCOS will go beyond the abovementioned objectives and is planning to test EPC in heterogeneous reactors, which is unprecedent. To do so, we are planning to (iv) anchor or support the iridium(III) catalysts directly onto the electrode. The impact of heterogenization can be tremendous: a more efficient population of the radical excited states, even at lower catalyst concentrations; an easier recovery of the reaction products, with simpler purification process and virtually no catalyst losses; the creation of an in-flow photoelectrochemical reactor for organic synthesis. As its final objective, HEPIrCOS will so aim to merge together 2 of the 4 key technological challenges expected to be faced by photochemistry for organic synthesis in the next years: electrophotochemistry and flow chemistry. An important impact in the field of green chemistry, catalysis and industrial chemistry is clearly envisaged in the long term, which is pivotal to reach the targets of the European Green Deal for making the European Union climate neutral in 2050.
Project details
Unibo Team Leader: Isacco Gualandi
Unibo involved Department/s:
Dipartimento di Chimica Industriale "Toso Montanari"
Coordinator:
CNR - Consiglio Nazionale delle Ricerche(Italy)
Total Unibo Contribution: Euro (EUR) 64.210,00
Project Duration in months: 24
Start Date:
28/09/2023
End Date:
28/02/2026
