meso-meso-Linked Diarylamine-Fused Porphyrin Dimers

A meso-meso-linked diphenylamine-fused porphyrin dimer and its methoxy-substituted analogue were synthesized from a meso-meso-linked porphyrin dimer by a reaction sequence involving Ir-catalyzed β-selective borylation, iodination, meso-chlorination, and S_N Ar reactions with diarylamines followed by electron-transfer-mediated intramolecular double C-H/C-I coupling. While these dimers commonly display characteristic split Soret bands and small oxidation potentials, they produced different products upon oxidation with tris(4-bromophenyl)aminium hexachloroantimonate. Namely, the diphenylamine-fused porphyrin dimer was converted into a dicationic closed-shell quinonoidal dimer, while the methoxy-substituted dimer gave a meso-meso, β-β doubly linked porphyrin dimer.