A study of out-of-plane cation dynamics in a bis-thiourea pyridinium chloride inclusion compound |
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Authors: | Pajzderska A Czarnecki P Embs J P Gonzalez M A Juranyi F Krawczyk J Peplińska B Wąsicki J |
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Institution: | Faculty of Physics, A. Mickiewicz University, Poznań, Poland. apajzder@amu.edu.pl |
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Abstract: | The out-of-plane motion of the pyridinium cation in the bis-thiourea pyridinium chloride inclusion compound has been studied in a wide temperature range using (1)H NMR, dielectric spectroscopy and quasielastic neutron scattering. The geometry of this motion is obtained from the Q-dependence of the elastic incoherent structure factor determined from the quasielastic neutron scattering measurements. We find that the pyridinium cation performs out-of-plane reorientations around the axis passing through two opposite atoms of the ring. The correlation times as a function of temperature were measured in the three known crystallographic phases, finding a good agreement between the three techniques employed. The activation energy for this motion changes from 5 ± 1 kJ mol(-1) in the low-temperature phase to 1.2 ± 0.2 kJ mol(-1) in the intermediate and high-temperature phases. |
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