New Ethylenedithio-TTF Containing a 2,2,5,5-Tetramethylpyrrolin-1-yloxyl Radical through a Vinylene Spacer and Its FeCl4− Salt—Synthesis, Physical Properties and Crystal Structure Analyses

Abstract

Abstract:To develop novel magnetic conductors exhibiting conducting/magnetic bifunctionalities and peculiar responses to applied magnetic fields, we synthesized new EDT-TTF (ethylenedithiotetrathiafulvalene) donor containing a 2,2,5,5-tetramethylpyrrolin-1-yloxyl radical through a π-conjugated vinylene spacer 1 and examined its electronic and crystal structures, and physical properties. We also prepared its cation radical salts by an electrochemical oxidation method and successfully cleared the crystal structures and magnetic properties of the cation radical salts, 1·FeCl 4 and 1·GaCl 4 . These salts have strongly dimerized one-dimensional arrays of the fully oxidized donor molecules, giving rise to the formation of spin-singlet state of the π cation radical spins in the dimer. On the other hand, the FeCl 4 − anion locates on the side of the dimers with very short S-Cl contacts and mediates very strong π-d interaction between the donor and anion moieties, resulting in the antiferromagnetic behavior of the Weiss temperature of θ = −3.9 K through its d-π-d interaction.

Magnetism of Molecular Conductors

“…In the contribution of Manuel Souto et al [6], a new molecular dyad is reported, based on a monopyrrolo-tetrathiafulvalene electron donor linked by a π-conjugated bridge to a perchlorotriphenylmethyl radical, with interesting properties and the potential to give rise to new radical conductors in the solid state. The combination of radical units with electroactive donor networks is another strategy for preparing magnetic conductors, and in this issue Kazuki Horikiri and Hideki Fujiwara describe charge transfer salts of a new EDT-TTF (ethylenedithiotetrathiafulvalene) donor containing a radical through a π-conjugated vinylene spacer, with diamagnetic GaCl 4 and paramagnetic FeCl 4 anions with strong π-d interactions [7]. Another contribution by Hiroki Akutsu et al describes two dmit-based salts with a stable organic radical-substituted ammonium cation, exhibiting magnetic contributions from segregated 2D anionic and cationic sub-lattices [8].…”