Synthesis, crystal structures and electrical properties of cation radical salts of selenium-containing π-extended donors, BEDT-HBDST and BEDT-HSTT

We have synthesized novel selenium-containing π-extended donors, BEDT-HBDST and BEDT-HSTT. The PF6, AsF6 and SbF6 salts of BEDT-HBDST showed broad ρmax at around 120, 95 and 85 K, respectively, and metallic behavior down to 2 K. The quasi-one-dimensional metallic band structures are calculated for the PF6 and AsF6 salts of BEDT-HSTT with an α′-type donor arrangement, although these salts showed semiconducting behavior.