Subporpholactone, Subporpholactam, Imidazolosubporphyrin, and Iridium Complexes of Imidazolosubporphyrin: Formation of Iridium Carbene Complexes.

Pyrrole-modified subporphyrins bearing a non-pyrrolic cyclic unit, subporpholactone, subporpholactam, and imidazolosubporphyrin were newly synthesized. They show subporphyrin-like absorption and fluorescence spectra that are red-shifted in the order of subporpholactam<subporpholactone<imidazolosubporphyrin. Metalation of the imidazolosubporphyrin with (pentamethylcyclopentadienyl)iridium(III) dichloride dimer gave a complex, in which the iridium(III) atom was attached at the peripheral nitrogen atom of the imidazole moiety and the ortho-position of the meso-phenyl group. Reaction of this complex with diphenylacetylene gave different products depending on the used additive; a phenyl-rearranged product in the presence of NaBArF4 (ArF =3,5-bis(trifluoromethyl)phenyl) and two isomeric carbene complexes in the presence of KPF6 .