Journal of Crystallographic and Spectroscopic Research

, Volume 18, Issue 5, pp 545–554

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

DOI: 10.1007/BF01161147

Cite this article as:
Marzotto, A., Clemente, D.A. & Pasimeni, L. Journal of Crystallographic and Spectroscopic Research (1988) 18: 545. doi:10.1007/BF01161147


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)22− anion dimers and two TPA+ cations inserted between the (DDQ)22− dimers, with an infinite stack running along b of the type ⋯(DDQ)22−[(C3H7)4N+] (DDQ)22−2[(C3H7)4N+]⋯

The (DDQ)22− 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)22− 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”.

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