Browsing by Author "Queckbörner, Jobst G."

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    Doped dialkylated phenazines : a novel series of highly conducting organic solids
    (1981) Dietz, Klaus; Flandrois, Serge; Keller, Heimo J.; Koch, P.; Queckbörner, Jobst G.; Schweitzer, Dieter
    Doping dimethylphenazine (M2P)-TCNQ and diethylphenazine (E2P)-TCNQ with phenazine gave rise to new conducting compounds with segregated stacks : (M2P)0.5 (P)0,5 TCNQ and (E2P)0,55 (P)0,45 TCNQ. The room temperature electrical conductivities are in the range 10-100 Ω-1 cm-1 for (1) and 1-10 Ω-1cm-1 for (2). The paramagnetism of both compounds could be separated into contributions from TCNQ and Phenazine stacks. The structural electrical and magnetic similarities of (1) with the well-known N-methylphenazinium (NMP)-TCNQ led to a reexamination of its magnetic properties. It was shown that an estimate of the charge transfer can be obtained from the temperature dependence of the magnetic susceptibility.
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    The preparation of new metallic charge-transfer complexes: anthra [9.1-cd:10.5-c'd'] bis [1.2] dithiol (TTA), -diselenol (TSA) and their polyiodides
    (1982) Endres, Helmut; Keller, Heimo J.; Queckbörner, Jobst G.; Veigel, Jürgen; Schweitzer, Dieter
    The donors TTA and TSA were prepared starting from 1.5-dichloro-9.10-anthracenedione which was converted into 1.5.9.10-tetrachloroan-thracene (TCA) by two alternating chlorination and elimination steps. TCA was reacted under a dry argon atmosphere with suspensions of Na2S2 and Na2Se2 to yield TTA and TSA, respectively. Action of elemental iodine gives highly conductive polyiodides of both donors. Single crystals of TSA·I1.2 actually behave metallic between 220 and 300 K. The X-ray structure of TSA and TSA·I1.2 allows a comparison of intermolecular distances in the neutral and the partially oxidized, ionic stacks of the donor.
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    Structure of anthra[9,1-cd:10,5-d'd']bis[1,2]-diselenole (TSA) and of its partially oxidized, metallic polyiodide TSA I1.2
    (1982) Endres, Helmut; Keller, Heimo J.; Queckbörner, Jobst G.; Schweitzer, Dieter; Veigel, Jürgen
    Tetraselenaanthracene' (TSA), C 14H6Se4' M r = 490·04, crystallizes in the monoclinic space group P2 1/n with a = 9·318 (3), b = 4·111 (1), c = 16·035 (4) A,β = 90·43 (2)°, V = 614·3 A3, Z = 2, d c = 2·65 Mg m-3• R = 0·030 for 1039 observed reflections. The planar molecules form stacks along b with an interplanar separation of 3·59 A. The normals to the molecular planes are inclined at 29° to the stacking axis. Short intermolecular Se-Se contacts exist between adjacent stacks, the shortest one being 3·467 (1) A. 'Tetraselenaanthracenium iodide' (TSA I 1.2), C14H6I 1.20Se4' Mr = 642·32, is monoclinic, P2 1/c, with a = 18·644 (12), b = 3·856 (2), c = 19·746(12)A,β= 93.36 (5)0,.V= 1417·1A3, dc = 3·01 Mg m-3• R = 0·118 for 1080 observed reflections.