The scope of the β-halogenation of triarylcorroles

Functionalization of corrole at its peripheral positions is an intriguing field of research, since the unusual reactivity of this macrocycle usually makes it difficult to predict the reaction products. We have investigated the introduction of halogen atoms at the corrole β-positions by using haloacids as reagents. Different behavior, in terms of number and position of the units introduced, was observed: chlorination yielded mono and disubstituted corrole, whereas bromination only afforded mono-substitution, even if on different positions. Iodination did not occur on the corrole free base, while the protection of the inner core by chelation with silver ion gave better results and a symmetric diiodinated corrole was isolated. 2D NMR analysis and X-ray crystallography provided useful information about the site of these corrole functionalizations.