[3 + 1] Mixed Cyclization: A Synthetic Route to Prepare Low-Symmetry Phthalocyanines.

A novel synthetic strategy for low-symmetry phthalocyanines has been developed, which involves the base-promoted cyclization of a preconnected trisphthalonitrile and a free phthalonitrile in the presence of a metal template. By using this [3 + 1] mixed cyclization approach, a series of zinc(II) phthalocyanine derivatives have been synthesized in up to 12% yields, including a very rare ABCD-type phthalocyanine and an amphiphilic ABAC-type analogue that can self-assemble in aqueous media, forming stable spherical nanoparticles.