Synthesis of a Fourfold Enlarged Porphyrin with an Extremely Large, Diamagnetic Ring‐Current Effect

Abstract

The [26]porphyrin 1·2 CF3COO⊖ exhibits remarkable properties. It is formed formally by insertion of four vinyl units into the porphyrin ring. The difference between the δ values of the inner and outer protons of 1·2CF3COO⊖ is extremely large (25.3 ppm)! For comparison, the value for [18]annulenes is 12.1 Noteworthy is also the extremely large ε value of over 900 000 as well as the biomimetic synthesis of the molecule from a monopyrrole.