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(T(i)PrP)ClO(4) and saddled Fe(OETPP)ClO(4) produces the corresponding six-coordinate iron(III) porphyrin(por) radical cations [Fe(Por·)(ClO(4))(2)], where T(i)PrP 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(T(i)PrP·)(ClO(4))(2)] exhibits no antiferromagnetic coupling, saddled [Fe(OETPP·)(ClO(4))(2)] does exhibit it. The difference in magnetic behaviors has been explained in terms of the deformation mode and electron configuration of these complexes.