Functionalized metal corroles for OER, ORR, and CO2 fixation reaction and the substrate-mediated generation of corrole radicals
Sprache des Vortragstitels:
Selective catalysts are urgently needed for the oxygen evolution reaction (OER), the oxygen reduction reaction (ORR) and CO2 fixation/reduction reactions (CO2RR) in order to replace fossil fuels with renewable fuels. To date, noble metals and precious metal catalysts have achieved the best performance in energy yield and Faradaic efficiency, and have recently reached impressive electrical-to-chemical power conversion efficiencies. However, the scarcity of precious metals makes the search for scalable, non-precious or even metal-free catalysts for the above mentioned reactions all the more important. During the lecture, I will discuss our synthesis efforts to develop functional materials based on metal corrole systems or polymeric materials and subsequently show their application as catalysts for OER/ORRs and CO2RR. Subsequently in the second part of the talk, radical on-surface cyclization reactions will be presented. Radical cyclization reactions are among the most powerful and versatile reactions for constructing mono- and polycyclic systems, but has, to date, remained unexplored in the context of on-surface synthesis. We report the controlled on-surface synthesis of stable corrole radicals on Ag(111) via site-specific dehydrogenation of a pyrrole N?H bond in the 5,10,15-tris(pentafluoro-phenyl)-corrole triggered by annealing at 330 K under ultrahigh-vacuum conditions. We reveal a thermally induced regioselective cyclization reaction mediated by a radical cascade and resolve the reaction mechanism of the pertaining cyclodefluorination reaction at the single-molecule level. Via intramolecularly resolved probing of the radical-related Kondo signature, we achieve real space visualization of the distribution of the unpaired electron density over specific sites within the corrole radical. Annealing to 550 K initiates intermolecular coupling reactions, producing an extended ?-conjugated corrole system.