Formation and crystal structure of a novel zinc phthalocyanine analogue having an axial isoindole ligand obtained by lithium-mediated reactions under mild conditions

The reaction of phthalonitrile and lithium methoxide at 70°C in methanol yields a half-phthalocyanine intermediate, which coordinates to a zinc(II) ion in a subsequent reaction step to afford a novel five-coordinate zinc phthalocyanine analogue 2, having axially coordinating diiminoisoindole and methoxy moieties bonded at diagonal positions of the pyrrole α-carbons. Although the chromatographic isolation of 2 is problematic, its crystal structure has been determined unambiguously. The importance of the effective ionic radius of the zinc(II) ion for the resultant molecular structures is discussed.