Isolation and characterization of the principal kinetic product in the preparation of a sterically hindered tetra-arylporphyrin: X-ray structure of a bis(dipyrromethene) complex of zinc, Zn II (C 22 H 13 Cl 4 N 2 ) 2 · toluene

The principal kinetic product in the Rothemund template synthesis of sterically hindered tetra-arylporphyrins is not the metalloporphyrin complex but the bis(dipyrromethene) complex; the latter has been isolated from a typical porphyrin preparation, that of tetrakis(2,6-dichlorophenyl)porphyrin, and characterized by u.v.–visible, i.r., and n.m.r. spectroscopy, and X-ray crystallography.