Bromide and Tribromide 4‑Cyanobenzene-Ethylenedithio-Tetrathiafulvalene Radical Salts by Chemical and Electrochemical Routes

Two salts of the dissymmetric TTF-derivative 4-cyanobenzene-ethylenedithio-tetrathiafulvalene (4-CNB-EDT-TTF) with bromide and tribromide anions and with different stoichiometries, namely, (1:1) (4-CNB-EDT-TTF)­Br3 (1) and (4:1) (4-CNB-EDT-TTF)4Br (2), were obtained by electrocrystallization and diffusion methods, respectively. The crystal structures of these compounds, as determined by single-crystal X-ray diffraction, are based on head-to-tail donor dimers with ring over ring overlap and donor stack arrangement, interleaved by anions depending on the (1:1) or (4:1) salt, respectively. The 4:1 salt behaves as a Mott insulator. In both salts, the donors are connected to adjacent donors through C–N···H–C interactions, which can be described as an modified R2 4 (10)* synthon for 1 and a combination of R2 2(10) and R2 4(10) synthons for 2.