Synthesis and physicochemical characterization of bis(macrocycles) involving a porphyrin and a meso-substituted corrole -: X-ray crystal structure of a [(free-base porphyrin)-corrole]bis(pyridine)cobalt complex

A very efficient, simple synthesis of face-to-face porphyrincorrole free-bases bearing substituents at the meso positions of the corrole ring is reported. Starting from the (porphyrinaldehyde)zinc species 1Zn, porphyrin-corrole free-bases (3M, 3C) are obtained in two steps, in fairly good yields (40-43%), compared to 11 steps for their corrole beta-pyrrole-substituted counterparts. Moreover, the possibility to directly synthesize the free-base (porphyrin-corrole) cobalt complex (5M or 5C) allows for the further preparation of heterodimetallic derivatives. Crystals of the bis(pyridine) adduct of 5M have been grown; the molecular structure clearly shows that the two pyridine molecules are coordinated to the cobalt ion in endo and exo positions, leading to an open-mouth geometry of the bis(macrocycle). The structure of 5M(py)(2)also shows intermolecular pi-pi interactions along the [100] direction, leading to stacking of the complexes. (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.