Inorganic Chemistry, Vol.42, No.26, 8638-8645, 2003
One-dimensional CuBr42- ion array and CuBr3- ion chain included in the pi conducting framework composed of bis(methylthio)tetrathiafulvalenothioquinone-1,3-dithiocarbonatodithiolemethide molecules
The reaction of a new donor molecule having a planar but largely bent skeleton, bis(methylthio)tetrathiafulvalenothioquinone-1,3-dithiocarbonatodithiolemethide (1), with CuBr2 in CH3CN/CS2 afforded a black-colored crystal with a formula of 1(4).CuBr4.2CuBr(3). In the crystal 1 molecules are one-dimensionally stacked to form half-cut pipelike columns, which are arranged to construct two different shapes of channels included by a one-dimensional array of CuBr42- ions and a bibromide-bridged linear chain of CuBr3- ions with a square-pyramidal geometry at the Cu atom, {CuBr3-}(n), respectively. The room-temperature electrical conductivity on the single crystal Of 1(4).CuBr4.2CuBr(3) was 2.0 x 10(-2) S cm(-1), and the temperature dependence of electrical conductivity was semiconducting with a large activation energy of 160 meV. The interactions between the neighboring Cu(II) d spins in the one-dimensional S = 1/2 spin systems due to CuBr42- ions and CuBr3- ions in {CuBr3-}(n) were both antiferromagnetic, and the magnitudes were moderate (Weiss temperature, Theta = -18 K) in the former spin system and fairly large (coupling constant, J/k(B) = -120 K) in the latter spin system, which was in marked contrast to a moderate and ferromagnetic {CuBr3-}(n) chain in the cyclohexylammonium salt already known.