Control of Aromaticity and cis ‐/ trans ‐Isomeric Structure of Non‐Planar Hexaphyrin(2.1.2.1.2.1) and Metal Complexes

Vinylene‐bridged hexaphyrin(2.1.2.1.2.1) was synthesized from dipyrrolyl diphenylethenes by acid‐catalyzed condensation reactions. Freebase hexaphyrin(2.1.2.1.2.1) forms a distorted structure with non‐aromatic characteristics. The aromaticity and molecular configuration of non‐planar hexaphyrin(2.1.2.1.2.1) can be controlled by insertion of metal ions. Freebase and zinc complexes show a distorted structure without macrocyclic aromaticity, whereas copper complexes show a figure‐of‐eight structure with macrocyclic aromaticity. It is the first example of aromaticity conversion of a distorted expanded porphyrin involving vinylene bridges.