SET and HAT/PCET acid-mediated oxidation processes in helical shaped fused bis-phenothiazines.

ABSTRACT: Helical shaped fused bis-phenothiazines 1-9 have been prepared and their red-ox behaviour quantitatively studied. Helicene radical cations (Hel^.+ ) can be obtained either by UV-irradiation in the presence of PhCl or by chemical oxidation. The latter process is extremely sensitive to the presence of acids in the medium with molecular oxygen becoming a good single electron transfer (SET) oxidant. The reaction of hydroxy substituted helicenes 5-9 with peroxyl radicals (ROO^. ) occurs with a 'classical' HAT process giving HelO^. radicals with kinetics depending upon the substitution pattern of the aromatic rings. In the presence of acetic acid, a fast medium-promoted proton-coupled electron transfer (PCET) process takes place with formation of HelO^. ra

SUBMITTER: Amorati R 

PROVIDER: S-EPMC8361695 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature