The Curious Case of a Parasitic Twin of the Corroles.

An expanded porphyrinoid has been obtained by a simple ring expansion from a contracted porphyrinoid, namely corrole. Spectroscopic, structural, and computational investigations reveal peculiar π-conjugation and geometry. The effect of extended π-conjugation is evident from perturbed redox behavior and photophysical properties. Owing to the strong diatropic ring current of the corrole and cross-conjugation, the molecule exhibits a non-aromatic nature for the expanded π-circuit, as evident from NMR studies.