Structures and physical properties of magnetic organic conductors based on bent donor molecule EDT-EDSe-TTFVS

The preparation, crystal structures, and physical properties of magnetic organic conductors based on a new bent donor molecule ethylenedithio-ethylenediseleno-tetrathiafulvalene-thioquinone-1,3-dithiolemethide (EDT-EDSe-TTFVS 3) are reported. The single crystals of 32FeCl4(EtOH) and 32FeBr4 are obtained by the electrochemical oxidation of 3 in the presence of (n-Bu4N)FeX4 (X = Cl, Br) at 45 °C. Semiconducting behavior is observed with moderate conductivities of 4.0 and 0.6 S cm−1 for 32FeCl4(EtOH) and 32FeBr4, respectively. In the crystal structures of both salts, the donor molecules and magnetic FeX4− ions form segregated layers. Within the organic layer, the donor molecules form columnar stacks, and the intra-columnar intermolecular overlap integrals are larger than the inter-columnar ones, resulting in the quasi one-dimensional electronic structures. There are atomic close contacts between the donor and FeX4 ion layers, which gives rise to the antiferromagnetic interaction of Fe(III) d-spins in both salts. Moreover, the Fe(III) d-spins in 32FeBr4 are subject to the antiferromagnetic ordering at 5 K due to the strong π–d and d–d interactions.