title: A study of out-of-plane cation dynamics in a bis-thiourea pyridinium chloride inclusion compound.
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.
authors.affiliation: Faculty of Physics, A. Mickiewicz University, Poznań, Poland. apajzder@amu.edu.pl
authors.forename: A
authors.initials: A
authors.lastname: Pajzderska
authors.forename: P
authors.initials: P
authors.lastname: Czarnecki
authors.forename: J P
authors.initials: JP
authors.lastname: Embs
authors.forename: M A
authors.initials: MA
authors.lastname: Gonzalez
authors.forename: F
authors.initials: F
authors.lastname: Juranyi
authors.forename: J
authors.initials: J
authors.lastname: Krawczyk
authors.forename: B
authors.initials: B
authors.lastname: Peplińska
authors.forename: J
authors.initials: J
authors.lastname: Wąsicki
mesh_terms: D002412:Cations / Q000737:chemistry; D008958:Models, Molecular; D011726:Pyridinium Compounds / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D002412:Cations; D011726:Pyridinium Compounds; C560816:bis-thiourea pyridinium chloride