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vol.53 número2LITHIUM COBALT SPINEL OXIDE: A STRUCTURAL AND ELECTROCHEMICAL STUDYSYNTHESIS AND CHARACTERIZATION OF THE LAMELLAR OXYCHLORIDE C0(2)CU4TE4O11CL4 índice de autoresíndice de assuntospesquisa de artigos
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Journal of the Chilean Chemical Society

versão On-line ISSN 0717-9707

Resumo

MERCHAN, JUAN et al. CONDUCTIVITY PROPERTIES OF THIOUREA- AND UREA-HALOGEN INCLUSION COMPOUNDS WITH DIQUINUCLIDINIUM CATION AS GUEST. J. Chil. Chem. Soc. [online]. 2008, vol.53, n.2, pp.1498-1502. ISSN 0717-9707.  http://dx.doi.org/10.4067/S0717-97072008000200011.

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]22+[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 assµmed 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 vacuµm, 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 vacuµm. Comparisons considering structural aspects are also discussed.

Palavras-chave : conductivity properties; supramolecular compounds; ternary urea and thiourea inclusion compounds.

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