Spin–spin interactions in iron(III) porphyrin radical cations with ruffled and saddled structure.

Oxidation of essentially pure intermediate-spin iron(III) porphyrinates such as ruffled Fe(TiPrP)ClO4 and saddled Fe(OETPP)ClO4 produces the corresponding six-coordinate iron(III) porphyrin(por) radical cations [Fe(Por)(ClO4)2], where TiPrP and OETPP are dianions of 5,10,15,20-tetraisopropylporphyrin and 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetraphenylporphyrin, respectively. Spin–spin interactions in these complexes are very much different; while ruffled [Fe(TiPrP)(ClO4)2] exhibits no antiferromagnetic coupling, saddled [Fe(OETPP)(ClO4)2] does exhibit it. The difference in magnetic behaviors has been explained in terms of the deformation mode and electron configuration of these complexes. [Copyright &y& Elsevier]