Universität Stuttgart
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Item Open Access 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, DieterDoping 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.Item Open Access Electrochemical synthesis of new one-dimensional metals: radical salts of perylene(1981) Keller, Heimo J.; Nöthe, Dietrich; Pritzkow, Hans; Wehe, Dieter; Werner, M.; Harms, Ralf H.; Koch, P.; Schweitzer, DieterThe electrochemical synthesis of four highly conducting peryleniumyl salts is reported. The temperature dependence of the conductivity has been measured and exhibits a metallic regime between 200-300 K. The crystal structures of two of the compounds have been solved.Item Open Access Optical detection of magnetic resonance (ODMR) of naphthalenophanes(1981) Schweitzer, Dieter; Hausser, Karl H.; Blank, Norman E.; Haenel, Matthias-Item Open Access Optical detection of magnetic resonance (ODMR) of triple-layered phanes(1981) Melzer, Guenter; Schweitzer, Dieter; Hausser, Karl H.; Staab, Heinz A.; Zapf, Udo-Item Open Access [2.2]- and [3.3]tetrathiafulvalenophanes(1980) Ippen, Joachim; Chu, Tao-pen; Starker, Barbara; Schweitzer, Dieter; Staab, Heinz A.In the "metallic" conducting 1:1 complex of tetrathiafulvalene (TTF) and tetracyanoquinodimethane (TCNQ), donor and acceptor molecules form separate stacks in the crystal. In order to enforce other TTF/TCNQ arrangements by altering the molecular architecture the phane-like bridged TTF-paracyclophanes (1), n = 3, and (2) were first synthesized. To do this a novel reaction sequence had to be developed which also facilitated synthesis of the tetrathiafulvalenophanes (3)/(4) (and the corresponding [2.2]-derivatives). (3)/(4) and TCNQ form a 1:4 complex having a conductivity of σ = 5 × 10−3 to 10−2 [Ω cm]−1 (single crystal, long axis, 300 K).Item Open Access Influence of an identified dimer vibration on the emission spectrum of [2,2]paracyclophane(1980) Goldacker, Wilfried; Schweitzer, Dieter; Dinse, Klaus Peter; Hausser, Karl H.The emission spectrum of polycrystalline [2,2]paracylophane shows a resolved vibronic structure with a 241 cm−1 progression at He temperatures. The dependence of the energy of this mode upon selective deuteration in combination with results from FIR and Raman spectra could be used to identify the mode as a torsional dimer vibration. The emission spectra could be simulated assuming a linear coupling of the torsional mode to the electronic transitions with coupling strengths of S = 10 (fluorescence) and S = 13 (phosphorescence). This corresponds to an equilibrium displacement of the benzene rings under electronic excitation by a torsional angle of 10.6° (S1) and 12.1° (T1), in addition to the small torsion in the ground state S0 by about 3°.Item Open Access [2.2]- und [3.3]Tetrathiafulvalenophane(1980) Ippen, Joachim; Chu, Tao-pen; Starker, Barbara; Schweitzer, Dieter; Staab, Heinz A.Um bei Charge-Transfer-Systemen, die als elektrische Halbleiter oder Leiter interessant sein könnten, durch Änderung der Molekularchitektur das Kristallgitter systematisch zu variieren, synthetisierten wir [2.2]- und [3.3]Tetrathiafulvalenophane ("TTF-Phane").Item Open Access ZFS-tensor of the triplet states of [2.2]phanes as studied by ESR(1981) Bär, Monika; Dinse, Klaus Peter; Goldacker, Wilfried; Hausser, Karl H.; Schweitzer, Dieter; Zimmermann, Herbert; Krieger, Claus-Item Open Access Electrochemically generated peryleniumyl-hexafluorophosphate and hexafluoroarsenate : new one-dimensional metals(1980) Keller, Heimo J.; Nöthe, Dietrich; Pritzkow, Hans; Wehe, Dieter; Werner, M.; Koch, P.; Schweitzer, DieterCompounds of stoichiometry (pe)2(PF6)1.1x times 0.8CH2Cl2(1) (pe = perylene), (pe)2(AsF6)1.1 timesx 0.7 CH2Cl2 (2), (pe)2(PF6)1.4 times 0.6 THF (3), (pe)2(AsF6)1.5x times 0.5 THF (4) and (pe)3(SbF6)2 times 0.75 CH2Cl2 (5) have been obtained as crystalline samples by electrochemical deposition from CH2Cl2 [(1), (2) and (5)] or from THF [(3) and (4)] solutions of perylene, containing the appropriate counterion. The three compounds (1)-(3) crystallize in isomorphous orthorhombic lattices. (1) forms black needles: space group Pnmn with a = 4.285 Aring, b = 12.915 Aring and c = 14.033 Aring, z = 1. (2) gives black needles, orthorhombic space group Pnmn with a = 4.294 Aring, b = 13.077 Aring, and c = 14.132 Aring, z = 1. The structures of (1) and (2) were solved by direct methods and refined by least squares to final R = 0.148 and R = 0.088 based on 476 and 322 observed reflections. The perylene forms segregated stacks in direction of the a-axis with interplanar distances of 3.40 Aring and an angle of 37.7° between the bc-plane and the perylene. The channels between the segregated stacks are filled by anions and solvent molecules. The d.c. conductivities (four probe measurements) of (1)-(4) fall in the range of 70-1200Ω-1. cm-1 at room temperature. The conductivities show a metallic regime down to about 200°K and drop off below that temperature.