Electronic Structures and Reactivities of Corrole−Copper Complexes

The spectroscopic and electrochemical examination of the mononuclear copper complexes of 5,10,15‐tris(pentafluorophenyl)corrole and 5,10,15‐tris(2,6‐dichlorophenyl)corrole ( 1a and 2a , respectively) and of the corresponding dinuclear corrole dimers 1b and 2b reveal the existence of two almost degenerate electronic states. The lower state consists of copper( III ) ions coordinated by closed‐shell corrolato trianions and the higher state is composed of copper( II ) ions chelated by open‐shell corrolato dianions. The contributions from both states are evident in the molecular structure of monomeric and mononuclear 2a , which displays a distorted square‐planar coordination geometry around the metal ion and short Cu−N bond lengths typical of copper( III ), together with some non‐equivalence of the C α −C meso bond lengths that might reflect the open‐shell character of the macrocycle. The latter state is most likely to be responsible for the dimerization process. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)