Complete σ* intramolecular aromatic hydroxylation mechanism through O2 activation by a Schiff base macrocyclic dicopper(I) complex

Abstract

In this work we analyze the whole molecular mechanism for intramolecular aromatic hydroxylation through O2 activation by a Schiff hexaazamacrocyclic dicopper(I) complex, [CuI2(bsH2m)]2+. Assisted by DFT calculations, we unravel the reaction pathway for the overall intramolecular aromatic hydroxylation, i.e., from the initial O2 reaction with the dicopper(I) species to first form a CuICuII-superoxo species, the subsequent reaction with the second CuI center to form a μ-η2:η2-peroxo-CuII2 intermediate, the concerted peroxide O–O bond cleavage and C–O bond formation, followed finally by a proton transfer to an alpha aromatic carbon that immediately yields the product [CuII2(bsH2m-O)(μ-OH)]2+.

Keywords

• aromatic hydroxylation
• C–H bond activation
• C–H functionalization
• copper
• DFT calculations
• mechanism
• Schiff base