N-Heterocycle-fused Ni(ii) porphyrin dimers upon heating of meso-amino Ni(ii) porphyrins in nitrobenzene

Abstract

Simple refluxing of meso-amino β–β linked Ni(II) porphyrin dimer 5 in nitrobenzene gave 1,4-dihydropyridine-fused dimer 9, which was oxidized with MnO₂ to give pyridine-fused porphyrinoid dimer 10. On the other hand, similar oxidation of meso, meso-diamino β–β linked Ni(II) porphyrin dimer 6 mainly provided 2,6-naphthyridine-fused dimer 11. The structures of dimers 9, 10, and 13 have been revealed to be roughly coplanar by X-ray analysis. These fused dimers exhibit significantly red-shifted Q-like absorption bands.