A Bottom-up Synthesis of Antiaromatic Expanded Phthalocyanines: Pentabenzotriazasmaragdyrins, i.e. Norcorroles of Superphthalocyanines.

The first example of an antiaromatic expanded phthalocyanine, classified as a norcorrole of a superphthalocyanine has been prepared and fully characterized. The newly developed phthalonitrile dimerization reaction was a crucial step, which allowed for the bottom-up synthesis of expanded phthalocyanines. Their structure was confirmed by single crystal X-ray diffraction analysis. The 20 π antiaromaticity of the macrocycles was suggested by optical and theoretical calculations.