Molecular structure of tetrapropylammonium-2,3-dichloro-5,6-dicyano-p-benzoquinone compared toM+ TCNQ (M+=Rb+, K+, Cs+, or organic cations; TCNQ=tetracyanoquinomethane) charge-transfer complexes

  • Armando Marzotto
  • Dore Augusto Clemente
  • Luigi Pasimeni


The crystal and molecular structure of tetrapropylammonium-2,3-dichloro-5,6-dicyano-p-benzoquinone (TPA+ DDQ) has been determined from single-crystal X-ray diffraction analysis. The crystals are monoclinic, space groupP21/n, witha=13.297(5),b=12.851(4),c=13.099(5) Å,β=101.34(2)°, andZ=4. The compound consists of discrete (DDQ) 2 2− anion dimers and two TPA+ cations inserted between the (DDQ) 2 2− dimers, with an infinite stack running along b of the type ⋯(DDQ) 2 2− [(C3H7)4N+] (DDQ) 2 2− 2[(C3H7)4N+]⋯

The (DDQ) 2 2− anion is formed by two DDQ anions dimerized through a crystallographic center of symmetry; each DDQ moiety is nearly planar and exhibits molecular dimensions similar to those found in analogous compounds. The comparison between the (DDQ) 2 2− anion and a neutral DDQ molecule clearly shows that bond lengths are markedly influenced by the 2-anionic charge. Tetrapropylammomum cation assumes a distorted tetrahedral configuration as observed in TEA+ DDQ (TEA+=tetraethylammonium cation). The data are discussed in connection with the electrical conductivity of “organic metals”.


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  1. Gordon, D., and Hove, J. (1973)J. Chem. Phys. 59, 3419.Google Scholar
  2. Hibma, Tj., and Kommandeur, J. (1975)Phys. Rev. 12, 2608.Google Scholar
  3. International Tables for X-Ray Crystallography, Vol. 4 (1974) (Kynoch, Birmingham, England), p. 99.Google Scholar
  4. Khidekel, M. L., and Zhilyaeva, E. I. (1981)Synth. Metals 4, 1.Google Scholar
  5. Mayerle, J. J., and Torrance, J. B. (1981)Bull. Chem. Jap. 54, 3170.Google Scholar
  6. North, A. C. T., Phillips, D. C., and Mathews, F. S. (1968)Acta Crystallogr. A24, 351.Google Scholar
  7. Pasimeni, L., Brustolon, M., Zanonato, P. L., and Corvaja, C. (1980)Chem. Phys.,51, 381.Google Scholar
  8. Sheldrick, G. M. (1976)SHELX-76, System of Computing Programs (University of Cambridge, Cambridge, England).Google Scholar
  9. Zanotti, G., Bardi, R., and Del Prà, A. (1980)Acta Crystallogr. B36, 168.Google Scholar
  10. Zanotti, G., Del Prà, A., and Bozio, R. (1982)Acta Crystallogr. B38, 1225.Google Scholar

Copyright information

© Plenum Publishing Corporation 1988

Authors and Affiliations

  • Armando Marzotto
    • 1
  • Dore Augusto Clemente
    • 2
  • Luigi Pasimeni
    • 3
  1. 1.Department of Inorganic Metallorganic and Analytical ChemistryUniversity of PadovaPadovaItaly
  2. 2.Department of Biology, Faculty of ScienceUniversity of LecceLecceItaly
  3. 3.Department of Physical ChemistryUniversity of PadovaPadovaItaly

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