Charge transfer salts of tetrathiafulvalene derivatives with magnetic iron(III) oxalate complexes: [TTF]7[Fe(ox)3]2·4H2O, [TTF]5[Fe2(ox)5]·2PhMe·2H2O and [TMTTF]4[Fe2(ox)5]· PhCN·4H2O (TMTTF = tetramethyltetrathiafulvalene)

Abstract

Three novel TTF (tetrathiafulvalene) and TMTTF (tetramethyltetrathiafulvalene) radical salts of monomeric and dimeric iron(III) oxalate magnetic complexes, [TTF]₇[Fe(ox)₃]₂·4H₂O 1, [TTF]₅[Fe₂(ox)₅]·2PhMe·2H₂O 2 and [TMTTF]₄[Fe₂(ox)₅]·PhCN·4H₂O 3, have been synthesized, and their structures and physical properties investigated. The structures for these semiconducting salts feature monodimensional stackings of the radical cations interleaved by the complexes [Fe(ox)₃]³⁻ and [Fe₂(ox)₅]⁴⁻, and solvent molecules. For the novel dinuclear complex [Fe₂(ox)₅]⁴⁻ antiferromagnetic exchange between the two iron atoms through the oxalate bridge was found.