Synthesis of Phthalocyanines with a Pentafluorosulfanyl Substituent at Peripheral Positions

The pentafluorosulfanyl (SF(5)) group is more electronegative, lipophilic and sterically bulky relative to the well‐explored trifluoromethyl (CF(3)) group. As such, the SF(5) 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 SF(5) group directly attached on their peripheral positions is disclosed. The key for this work is the preparation of a series of SF(5)‐containing phthalonitriles, which was beautifully regio‐controlled by a stepwise cyanation via ortho‐lithiation/iodination from commercially available pentafluorosulfanyl arenes. The macrocyclization of the SF(5)‐containing phthalonitriles to SF(5)‐substituted Pcs required harsh conditions with the exception of the synthesis of β‐SF(5)‐substituted Pc. The regiospecificity of the newly developed SF(5)‐substituted Pcs observed by UV/Vis spectra and fluorescence quantum yields depend on the peripheral positon of the SF(5) group.