Neo‐Fused Hexaphyrin: A Molecular Puzzle Containing an N‐Linked Pentaphyrin

Abstract

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.

Expanded Porphyrins: More Confusion All the Time

“…In contrast, Xie et al developed a convenient and effective strategy for the synthesis of novel confused porphyrinoids by oxidative ring-closure reactions of linear oligopyrranes containing two terminal confused pyrroles. [9,10] This approach was demonstrated to be effective for synthesizing the first examples of expanded porphyrinoids with two directly linked confused pyrroles, which showed unique cooperative reactivity; unique macrocycle contraction, expansion, fusion, and opening reactions were thus successfully performed under mild reaction conditions. Various novel porphyrinoids with unique bipyrrole linking modes In summary, oxidative ring-closure reactions of oligopyrranes containing two terminal confused pyrroles are effective methods for the synthesis of porphyrinoids with two directly linked confused pyrroles, which show cooperative reactivity, and thus constitute a new method for the synthesis of novel porphyrinoids with unconventional pyrrole linking modes and unique properties.…”

Macrocyclic Transformations from Norrole to Isonorrole and an N‐Confused Corrole with a Fused Hexacyclic Ring System Triggered by a Pyrrole Substituent

“…[19] Considering the formation of doubly fused corrole analogue L4,f rom am echanistic viewpoint the singly fused corrole L3 can be regarded as an intermediate containing af used [5.7.6.5]-tetracyclic ring with one of the pyrrolic NH moieties,s pecifically,e ither the N-confused or the appended one.T oprovide further details on the N À C Ar bond formation occurring in L3,the relative energies of the plausible isomers and conformers of L3 were examined by DFT calculations (Figure 3). [20] These observations may be rationalized by the presence of as trong intramolecular hydrogen bond between the outer NH and the carbonyl Oatom. [6c] Moreover,t he chemical shift for the outer NH moiety in L3 is insensitive to the solvent media (for example in CDCl 3 or [D 6 ]DMSO; Figure S13).…”

Frontispiece: New Phosphorus‐Doped Perovskite Oxide as an Oxygen Reduction Reaction Electrocatalyst in an Alkaline Solution

“…[29] The presence of mesopores furthermore enables facile transport for ORR-related species, such as H + ,O H À ,H 2 O, and O 2 . [30] This observation highlights the opti-mised morphology as another contributing factor behindt he superior ORR activity of LSMP0.05.…”