Magnetic Resonance on (QP)4(SbF6)3, a Radical Cation Salt of P-Quaterphenylene |
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| Authors: | W Grauf J U Von SchÜTz H-P Werner H C Wolf Karin Göckelmann V Enkelmann |
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| Institution: | 1. 3. Physikalisches Institut , Universit?t Stuttgart , Pfaffenwaldring 57, D-7000 Stuttgart 80, W. Germany;2. Max-Planck-Institut für Polymerforschung , Jakob-Welder-Weg 73, D-6500, Mainz, W. Germany;3. 3. Physikalisches Institut , Universit?t Stuttgart , Pfaffenwaldring 57, D-7000 Stuttgart 80, W. Germany |
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| Abstract: | Abstract The unit cell of (QP)4(SbF6)3 shows triads of QP in an arene stack and one QP in the anion sheet. The sum formula is therefore (QP)3QP(SbF6)3. Electron-electron repulsion force le?/site resulting in a semi-conducting state. This is in agreement with an activated conductivity of max 10?1 Scm?1 at 300 K. Magnitude and activation energy of the paramagnetic susceptibility do not coincide with those of the conductivity; spins and charges are localized and decoupled due to the strong alternation of distances within the cation stack. Spin diffusion along the stacks governs, at least above 180 K, the magnetic properties: narrow ESR-lines and proton spin relaxation via hyperfine interaction with the relaxation dispersion T ?1 1H α ω?1/2 above 200 K. A lower value for the intrachain exchange rate τ1 ?1> 8.1011 sec?1 and a lower limit of 103 for the anisotropy can be evaluated. Keywords: quaterphenylene, molecular crystal, radical cation salt, low dimensionality, magnetic resonance |
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