Synthesis of Ni II porphyrin-Ni II 5,15-diazaporphyrin hybrid tapes.

Ni II porphyrin (P) and Ni II 5,15-diazaporphyrin (DAP) hybrid tapes were synthesized by Suzuki-Miyaura cross-coupling reactions of meso - or β-borylated P with β-brominated DAP followed by intramolecular oxidative fusion reactions. Meso -β doubly linked hybrid tapes were synthesized by oxidation of singly linked precursors with DDQ-FeCl 3 . Synthesis of triply linked hybrid tapes was achieved by oxidation with DDQ-FeCl 3 -AgOTf with suppression of peripheral β-chlorination. In these tapes, DAP segments were present as a 20π-electronic unit, but their local antiaromatic contribution was trivial. Remarkably, these hybrid tapes were stable and exhibited extremely enhanced absorption bands in the NIR region and multiple reversible redox waves. A pentameric hybrid tape showed a remarkably sharp and red-shifted band at 1168 nm with ε = 5.75 × 10 5 M -1 cm -1 . Singly linked P-DAP dyads were oxidized with DDQ-FeCl 3 to give stable radicals, which were oxidized further to afford dimeric hybrid tapes possessing a nitrogen atom at the peripheral-side meso -position.