摘要：An organic anion, 2-bromoethanesulfonate (BrC<sub>2</sub>H<sub>4</sub>SO<sub>3</sub><sup>−</sup>), provides one bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and two bis(ethylenedithio)tetraselenafulvalene (BETS) salts, the compositions of which are β’’-β’’-(BEDT-TTF)<sub>2</sub>BrC<sub>2</sub>H<sub>4</sub>SO<sub>3</sub> (<b>1</b>), β’’-β’’-(BETS)<sub>2</sub>BrC<sub>2</sub>H<sub>4</sub>SO<sub>3</sub> (<b>2</b>), and θ-(BETS)<sub>2</sub>BrC<sub>2</sub>H<sub>4</sub>SO<sub>3</sub> (<b>3</b>), respectively. Compound <b>1</b> shows a metal–insulator transition at around 70 K. Compound <b>2</b> is isomorphous to <b>1</b>, and <b>3</b> is polymorphic with <b>2</b>. Compounds <b>2</b> and <b>3</b> show metallic behavior at least down to 4.2 K. The pressure dependence of the electrical resistivity of <b>1</b> is also reported.
