Crystal structure and conduction property of the first quasi-one-dimensional conductor of tetrathiafulvalenium salt with mixed inorganic anions, (TTF)(ClO 4) 0.14±0.02(Cl) 0.42±0.08

Abstract

The first quasi-one-dimensional tetrathiafulvalenium conductor with mixed non-stoichiometric inorganic anions, (TTF)(ClO 4) 0.14±0.02(Cl) 0.42±0.08, was crystallized electrochemically and found to have a structure of a tetragonal system with a = b = 11.213(2) A ̊ , c = 3.600(1) A ̊ , Z = 2 . Crystal structure was analyzed assuming the space group of P4 2/ mnm. TTF radicals form stable segregated eclipsed stacks along the elongated c-axis but anions are fully disordered in the channels surrounded by the TTF stacks. The room temperature conductivity along the TTF stacks is 7–27 S/cm/. The conductor shows a sharp metal-insulator transition at 253±4 K and below this temperature it behaves as a one-dimensional variable range hopping (VRH) conductor down to 70 K. Another non-stoichiometric perchlorate of TTF, (TTF)(ClO 4) 0.62±0.02, was also obtained in polycrystalline form at the same electrochemical preparation and found to have a much lower powder conductivity (7 × 10 −4 S/cm) which suggests a possible Peierls structure at room temperature for this compound.