Synthesis of nickel(II)-containing meso-edited phthalocyanine derivatives

Abstract

In contrast to the rich chemistry of porphyrin and its analogs, the structural variety of phthalocyanine derivatives, which are widely utilized in material and life sciences, has been limited by the lack of versatile synthetic methods. Herein we present a synthetic strategy/methodology for the meso-position editing of phthalocyanine derivatives via deprotonative macrocyclization of open-form acyclic phthalonitrile Ni tetramer 1, prepared by thiolate-mediated reductive tetramerization of phthalonitrile and metalation. To illustrate the utility of this protocol, we synthesize several meso-N-edited phthalocyanine derivatives, including 16π-electron antiaromatic tetrabenzodiazanorcorrole 2, and 17π-electron paramagnetic tetrabenzotriazacorrole 3 and tetrabenzodiazacorrole 4. The products are obtained as the nickel(II) complexes. Their unique electronic properties, such as paratropicity and radical character, are characterized both experimentally and computationally. Moreover, antiaromatic compound 2 undergoes further meso-position and skeletal transformations upon reaction with nucleophiles to give nonaromatic and aromatic π-conjugates.