The first neo-confused hexaphyrin(1.1.1.1.1.0) was synthesized by oxidative ring closure of a hexapyrrane bearing two terminal "confused" pyrroles. The new compound displays a folded conformation with a short interpyrrolic C⋅⋅⋅N distance of 3.102 Å, and thus it readily underwent ring fusion to afford a neo-fused hexaphyrin with an unprecedented 5,5,5,7-tetracyclic ring structure. Furthermore, coordination of Cu(II) triggered a ring opening/contracting reaction to afford a Cu(II) complex of an N-linked pentaphyrin derivative. The roles of reactive N-C bonds in the porphyrinoid macrocycles were demonstrated.
Keywords: fused-ring systems; hexaphyrins; macrocycles; pentaphyrins; porphyrinoids.
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