Multiple conformational changes of beta-tetraphenyl meso-hexakis(pentafluorophenyl) substituted [26] and [28]hexaphyrins(1.1.1.1.1.1).

Beta-tetraphenyl meso-hexakis(pentafluorophenyl) substituted [26]hexaphyrin is conformationally flexible between rectangular and figure-of-eight shapes and its two-electron reduced [28]hexaphyrin takes figure-of-eight conformations, which are changed, upon protonation, to twisted conformations with distinct Möbius aromaticity.

Facile formation of a benzopyrane-fused [28]hexaphyrin that exhibits distinct Möbius aromaticity.

A benzopyrane-fused [28]hexaphyrin, 2, was prepared by simple heating of [26]hexaphyrin 1 in acetic acid. Fused [28]hexaphyrin 2 features a molecular twist, a distinct diatropic ring current, a large HOMA value, a large negative NICS value, and a large two-photon absorption (TPA) cross section even at room temperature, all of which support the Möbius aromaticity of 2. To the best of our knowledge, 2 is the first macrocycle that acquires distinct Möbius aromaticity without any assistance from metal coordination, temperature control, or protonation.

Phosphonium ylides from nucleophilic addition of triphenylphosphine to [26]hexaphyrin(1.1.1.1.1.1).

[reaction: see text] Nucleophilic addition of triphenylphosphine to neutral meso-hexakis(pentafluorophenyl)-substituted [26]hexaphyrin(1.1.1.

Thermal splitting of Bis-Cu(II) octaphyrin(1.1.1.1.1.1.1.1) into two Cu(II) porphyrins.

When heated, bis-Cu(II) octaphyrin(1.1.1.