| Abstract | dc.description.abstract | Thiourea and urea can modify their typical host properties to form new ternary polymolecular anionic halogen hosts in which the diquinuclidinium cation is
included. A comparative study of the proton conductivity properties of this kind of inclusion compounds is presented. The hexagonal binary inclusion compound
[quinuclidine]3thiourea 1 was taken as reference. The study shows the conductivity properties of [quinuclidine2H]+[thiourea2Cl]- 2, [quinuclidine2H]+[thiourea2Br]-
3, [quinuclidine2H]2
2+[thiourea2I2]2- 4, [quinuclidine2H]+[urea5Cl]- 5, [quinuclidine2H]+[urea2Br]- 6, and [quinuclidine2H]+[urea2I]- 7. Ionic conductivities of all the
compounds in pellets, and of 2 and 3 in large single crystals were measured by electrochemical impedance spectroscopy (EIS). Anisotropic conductivity behaviour
in crystals of adequate dimensions of 2 and 3 was detected. The conductivity values of 2 and 3 in the crystals were 2.19x10-4 and 6.03x10-6 (S/cm), respectively,
in the assumed channel direction, and 2.42x10-6 and 8.27x10-9 (S/cm), respectively, in the perpendicular direction to the former, at 298 K. Conductivities at room
temperature of the thiourea-halide derivatives in pellets show a changing behaviour from insulator (10-11 S/cm) for 2, 3 and 4 measured in vacuum, to semiconductor
(10-7-10-8S/cm) for the thiourea-halide derivative measured at atmospheric pressure. For the urea-halide system the highest conductivity value corresponds to
derivative 7 (8.66x10-5 S/cm) at atmospheric pressure, and the lowest to derivative 5 (5.48x10-7 S/cm) measured in vacuum. Comparisons considering structural
aspects are also discussed. | en_US |
