Doubly N-confused hexaphyrin: a novel aromatic expanded porphyrin that complexes bis-metals in the core.

Meso-hexakis(pentafluorophenyl)-substituted doubly N-confused hexaphyrins and their metal complexes were synthesized for the first time, and the structures were elucidated by X-ray single-crystal analyses. The free base form of oxidized hexaphyrin (5) had two preorganized N3O pockets in the macrocyclic core, where a hydrogen-bonding network was formed to keep the molecule planar (the mean plane deviation is 0.054 A). The formation of a planar bis-Cu(II) complex was confirmed by UV/vis, magnetic susceptibility measurements, and X-ray crystallography. The bis-Ni(II) complex (7), on the other hand, was distored from planarity, but it changed to the planar structure upon solvent (acetonitrile) coordination as judged by the observation of a sharp Soret-like band in absorption spectra and the X-ray structures of the complexes.