BiIII-Corroles: A Versatile Platform for the Synthesis of Functionalized Corroles

The BiIII ion in the center of the corrole macrocyclic ring system was employed to stabilize and protect the corrole inner core during the functionalization at the periphery (meso positions) of the π‐conjugated ring system. Moreover, the ease of demetalation makes BiIII–corroles attractive candidates for functionalization and subsequent demetalation to the free‐base corroles. Herein we present examples of possible derivatization reactions of Bi–corroles by employing Suzuki cross‐coupling under gentle conditions at ambient temperature. This high‐yielding methodology facilitates the design of A2B corroles that bear elaborate subunits such as the indolyl and pyrenyl group, which are difficult to realize with the synthetic protocols available to date. Later, Pd‐catalyzed C–N coupling reactions with the same precursor were tested. To make the corresponding free‐base corroles also accessible by means of these new routes, a versatile procedure was developed that allows the subsequent demetalation of the obtained Bi–corroles. Electrochemical characterization was performed with cyclic voltammetry and spectroelectrochemistry to clarify the ring‐centred oxidation and reduction processes. Structural considerations of the dome‐shaped nature of Bi–corrole derivatives are presented and corroborated by 19F NMR spectroscopy as well as quantum chemical calculations. The BiIII ion in the center of the corrole macrocyclic ring system was employed to stabilize and protect the corrole inner core during the functionalization at the periphery (meso positions) of the π‐conjugated ring system. The ease of demetalation makes BiIII–corroles attractive candidates for functionalization and subsequent demetalation to the free‐base corroles.