Lawrence Berkeley National Laboratory

Presented herein is a study of the acid-induced demetalation of two sterically hindered copper corroles, Cu β-octabromo-meso-triphenylcorrole (Cu[Br₈TPC]) and β-octakis(trifluoromethyl)-meso-tris(p-methoxyphenyl)corrole (Cu[(CF₃)₈TpOMePC]). Unlike reductive demetalation, which affords the free-base β-octabromocorrole, demetalation of Cu[Br₈TPC] under non- reductive conditions (CHCl₃/H₂SO₄) resulted in moderate yields of free-base 5- and 10-hydroxy isocorroles. The isomeric free bases could be complexed to Co^II and Ni^II, affording stable complexes. Only reductive demetalation was found to work for Cu[(CF₃)₈TpOMePC], affording a highly saddled, hydrated corrole, H₃[5-OH,10-H-(CF₃)₈TpOMePC], where the elements of water had added across C₅ and C₁₀. Interaction of this novel free base with Co^II resulted in Co[iso-10-H-[CF₃)₈TpOMePC], a Co^II 10-hydro isocorrole. The new metal complexes were all characterized by single-crystal X-ray diffraction analysis and, despite their sterically hindered nature, were found to exhibit almost perfectly planar isocorrole cores.