Synthesis,Characterization and Properties of Expanded Pyriporphyrins: A New Family of Alkylidenyl Porphyrin Homologues Bearing meso‐Exocyclic Double Bonds

We present the synthesis and characterization of a new family of expanded meso‐alkylidenyl (2,6‐pyri)porphyrinoids bearing multiple exocyclic double bonds at the meso‐positions. The synthesis was accomplished by using mixed pyrrole condensation. Similar to meso‐alkylidenyl porphyrinoids, this study revealed that pyriporphyrinoids do not possess a porphyrin‐like, global‐aromatic character. The synthesized 2,6‐pyripentaphyrin 1 displays selective ratiometric sensing of pyrophosphate anion in organic solvent.