Facile Synthesis of Large meso ‐Pentafluorophenyl‐Substituted Expanded Porphyrins

Acid‐catalyzed condensation of meso ‐pentafluorophenyl dipyrromethane 1 (100 m M ) and pentafluorobenzaldehyde 2 (100 m M ) at 0 °C gave a series of expanded porphyrins with even number of pyrrolic subunits up to octadecaphyrin(1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1) 18 in improved yields, particularly for larger expanded porphyrins. The solid‐state structure of decaphyrin(1.1.1.1.1.1.1.1.1.1) 10 was revealed by X‐ray diffraction analysis to be a crescent‐like conformation. The Soret‐like absorption bands are increasinglyredshifted as the size of the ring increases, but such atrend becomes nearly saturated for hexadecaphyrin(1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1) 16 and 18 , which exhibit bands in the near‐infrared region at 939 and 953 nm, respectively.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)