A Porphyrin Fused to Four Anthracenes

We have synthesized a fused tetraanthracenylporphyrin by oxidation of a meso-anthracenyl nickel(11) porphyrin with FeCl3. This compound exhibits an intense red-shifted absorption spectrum (lambda(max) = 1417 nm; epsilon = 1.2 x 10(5) M-1 cm(-1)) and a small electrochemical HOMO-LUMO gap (0.61 eV). The crystal structure shows that it forms pi-stacked dimers with a short Ni center dot center dot center dot Ni distance (3.32 angstrom).