Conformational Effects on the Redox Potentials of Tetraarylporphyrins Halogenated at the β-Pyrrole Positions (pages 348–350)
Philippe Ochsenbein, Khadija Ayougou, Dr. Dominique Mandon, Prof. Dr. Jean Fischer, Prof. Dr. Raymond Weiss, Rachel N. Austin, Dr. Karupiah Jayaraj, Prof. Dr. Avram Gold, Prof. Dr. James Terner and Dr. Jack Fajer
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403481
Despite four additional electron-withdrawing substituents, the octahalogenated porphyrins 2 are more easily oxidized than their tetra-halogenated counterparts 1. This apparent paradox can be explained by the structures of the molecules: porphyrins 2 are almost planar, whereas in 1 steric interactions are minimized by a saddle conformation, which makes these porphyrins easier to oxidize.