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Abstract: A new BEDT-TTF-based radical salt, β-(BEDT-TTF)(HSO4) [BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene], has been synthesized by oxidative electrocrystallization. The crystal structure was determined by four-circle X-ray diffraction. The crystal belongs to monoclinic system, C2/c space group with the unit cell parameters of: a =1.5996(2)nm, b =1.06173(10)nm, c =1.15083(11)nm, β =120.534(8)°, V =1.6834(3)nm3, and R =0.0611. In the title crystal, the BEDT-TTF radicals are stacked to form columns along the [101] axis and the molecular planes of BEDT-TTFs in adjacent columns are parallel to each other. The inter-stack side-by-side S…S short contacts along the b-axis help to form a kind of cationic conducting sheet parallel to (101) plane. The room temperature conductivity at certain direction on (101) plane of β-(BEDT-TTF)(HSO4) single crystal was measured to be 11.7Scm−1. From 100K to 290K, the resistivity–temperature curve demonstrates its typical semiconductivity with an excitation energy of 0.26eV. [Copyright &y& Elsevier]

Abstract: A new molecular conductor (n-Bu4N)[Ni(dmit)2]4·MeCN (dmit=2-thioxo-1,3-dithiole-4,5-dithiolato) has been synthesized and its X-ray structure has been determined. The crystal exhibits conductivity 0.1Ω−1 cm−1 at room temperature and a semi-conducting behavior with small activation energy of 0.170eV (at 295K) and 0.065eV (at 95K). The coordination anions are arranged in a parallel fashion in the crystal forming two-dimensional networks, in which the face-to-face π–π longitudinal intermolecular interactions are stronger than the side-by-side S⋯S transverse interactions. The anionic stacks along the b-direction exhibit a type of tetrad structure. Infrared spectra suggest that the tetrad {4[Ni(dmit)2]}− may consist of one mono-anion [Ni(dmit)2]− and three neutral [Ni(dmit)2] units. The bond analysis further suggests that the single electron in the HOMO of [Ni(dmit)2]− can delocalize to its two neighboring [Ni(dmit)2] molecules to some extent. [Copyright &y& Elsevier]

A new molecular conductor (PyMe)[Ni(dmit)2]2 (PyMe = N-methylpyridinium, dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato) has been synthesized and its structure been determined. The temperature-dependent conductivities in the range of 290–20 K reveal a semi-conducting behavior of the crystal with a small activation energy of 0.067 eV and a quite high room temperature conductivity of 2 S cm−1. [Copyright &y& Elsevier]