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] 3 thiourea 1 was taken as reference. The study shows the conductivity properties of [quinuclidine 2 H]+[thiourea 2 Cl]- 2, [quinuclidine 2 H]+[thiourea 2 Br]3, [quinuclidine 2 H] 2 2+[thiourea 2 I 2 ]2- 4, [quinuclidine 2 H]+[urea 5 Cl]- 5, [quinuclidine 2 H]+[urea 2 Br]- 6, and [quinuclidine 2 H]+[urea 2 I]- 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.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call