Synthesis of Phthalocyanines with a Pentafluorosulfanyl Substituent at Peripheral Positions

The pentafluorosulfanyl (SF₅) group is more electronegative, lipophilic and sterically bulky relative to the well‐explored trifluoromethyl (CF₃) group. As such, the SF₅ group could offer access to pharmaceuticals, agrochemicals and optoelectronic materials with novel properties. Here, the first synthesis of phthalocyanines (Pcs), a class of compounds used as dyes and with potential as photodynamic therapeutics, with a SF₅ group directly attached on their peripheral positions is disclosed. The key for this work is the preparation of a series of SF₅‐containing phthalonitriles, which was beautifully regio‐controlled by a stepwise cyanation via ortho‐lithiation/iodination from commercially available pentafluorosulfanyl arenes. The macrocyclization of the SF₅‐containing phthalonitriles to SF₅‐substituted Pcs required harsh conditions with the exception of the synthesis of β‐SF₅‐substituted Pc. The regiospecificity of the newly developed SF₅‐substituted Pcs observed by UV/Vis spectra and fluorescence quantum yields depend on the peripheral positon of the SF₅ group.