Magnetic interaction of tri- and di-oxytriphenylamine radical cation FeCI4 salts

The tetrachloroferrates of the 2,2':6',2 '':6 '',6-trioxytriphenylamine (TOT center dot+center dot FeCl4-) and 2,2':6',2 ''-dioxytriphenylamine (DOT center dot+center dot FeCl4-) radical cations were prepared, and their structures, magnetic properties, and the relationship between them were investigated. The TOT center dot+ moiety had a highly planar structure and packed as a dimer surrounded by tetrachroferrates, which also formed a dimer structure. The magnetic properties of TOT center dot+center dot FeCl4- were characterized by strong (2J/k(B) = similar to -1.3 x 10(3) K, H = -2JS(1/2)center dot S-1/2) and weak (2J/k(B) = -1.76 K, H = -2JS(5/2)center dot S-5/2) antiferromagnetic interactions due to the (TOT center dot+)(2) and (FeCl4-)(2) structures, respectively. DOT center dot+ had a twisted form and no dimer formation was observed between the DOT center dot+'s and FeCl4-'S. Instead, short contacts between the DOT center dot+ and chlorine atoms and between the DOT center dot+'s producing a DOT center dot+ chain were observed. The magnetic properties of DOT center dot+center dot FeCl4- were characterized by a 3D magnetic phase transition to an antiferromagnet with T-N = similar to 8 K.