Demetalation of corrole complexes: An old dream turning into reality

Different strategies for the demetalation of corrole complexes have been developed, using copper complexes of corrole as model compounds. Best results were obtained using the acidic mixture CHCl3/H2SO4, which allowed the almost complete removal of copper ions from both meso-triaryl-, β-octaalkyl- and fully substituted corroles. This route reduced both the decomposition of the starting complex and the formation of isocorrole species produced by oxidation of the corrole ring in the acidic conditions necessary for the demetalation reaction. To investigate the scope of the reaction, the same approach was later extended to other metal complexes of corrole, such as cobalt, manganese, iron and germanium derivatives. Although not always successful, this approach demonstrated that in the case of corrole it is also possible to obtain a reversible coordination of metal ions, a route of synthetic interest for further functionalization of the corrole ring. Copyright © 2008 Society of Porphyrins & Phthalocyanines.