Influence of β-octabromination on free-base triarylcorroles: Electrochemistry and protonation-deprotonation reactions in nonaqueous media

Electrochemical and acid-base properties of four free-base triarylcorroles were examined in nonaqueous media. These compounds are represented here as (tdcc)H-3, (tpfc)H-3, (Br(8)tdcc)H-3 and (Br(8)tpfc)H-3, where tdcc and tpfc are the trianions of tris(2,6-dichlorophenyl) corrole and tris(pentafluorophenyl) corrole, respectively. Different spectroscopic and electrochemical properties were observed for the beta-brominated corroles as compared to the non-brominated derivatives, due in part to the corrole ring distortion and in part to the strong electron-withdrawing properties of the Br groups. The brominated free-base corroles are easier to deprotonate than the non-brominated corroles in solution, which was confirmed by electrochemistry and spectroelectrochemistry as well as protonation/deprotonation reactions of the compounds with acid or base in PhCN. The electrochemistry of the protonated and deprotonated corroles is presented and comparisons made with previously published data for other protonated and deprotonated free-base corroles under the same solution conditions.