Crystal and Molecular Structure of an Unusual Salt Formed from the Radical Cation of Tetrathiafulvalene (TTF) and the Trichloromercurate Anion (HgCl3), (TTF)(HgCl3)

T. J. Kistenmacher, M. Rossi, C. C. Chiang, R. P. VanDuyne, A. R. Siedle

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Abstract

The synthesis and crystal structure of the salt (TTF)(HgCl3) are reported. Crystals of the salt are triclinic, of space group PI, with a = 12.661 (3) k, b= 15.969 (4) Å, c = 7.416 (2) Å, α = 98.69 (2)°, β = 95.73 (2)°, γ = 120.01 (2)°, V = 1256.2 A3, mol wt ((C6H4S4)(HgCl3)) = 511.3, Z = 4, Dmeasd = 2.68 (1) g cm-3, and = 2.70 g cm-3. The structure was solved by standard Patterson and Fourier methods and has been refined by full-matrix least squares, based on 4298 counter-collected F0's, to a final R value of 0.080. The structure can be qualitatively separated into two layers parallel to the ac plane. One of these layers, centered about y = 0.0, contains both inorganic and organic polymers propagating along the crystallographic c axis. The covalent inorganic polymer contains roughly trigonal-bipyramidal coordination about the Hg(II) center, with equatorial Hg-Cl bond lengths of 2.374 (5), 2.395 (5), and 2.545 (5) Å and considerably longer axial bond lengths of 2.982 (5) and 3.112 (5) Å. Collinear with this covalent inorganic polymer is a columnar array of stacked TTF radical cations. The stacking in this columnar array of TTF cations is nominally of the ring-over-bond type with a mean separation between planes of 3.6 Å. The second layer, centered about y = 0.5, contains solely dimeric species. The chloromercurate anion is a dimeric, edge-shared bitetrahedron, with Hg-Cl bond lengths of 2.600 (5) and 2.696 (5) Å for the bridging chloro ligands and 2.368 (5) and 2.381 (5) Å for the two independent terminal chloro ligands. The organic dimer is made up of two strongly associated and nearly eclipsed TTF cations, with a mean spacing of 3.43 Å. Resonance Raman data have been interpreted as suggesting the presence of two different kinds of TTF moieties, consistent with the X-ray data. From the Raman data it is indicated that the two different TTF species have slightly different degrees of charge transfer.

Original languageEnglish (US)
Pages (from-to)3604-3608
Number of pages5
JournalInorganic chemistry
Volume19
Issue number12
DOIs
StatePublished - Dec 1 1980

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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