On-Surface Site-Selective Cyclization of Corrole Radicals
Sprache des Titels:
Englisch
Original Kurzfassung:
Radical cyclization is 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.