STRUCTURAL AND SPECTROSCOPIC PROPERTIES OF THE 1/1 COMPLEX OF DELTA-2,2'-BIS-1,3-DITHIOLE (TTF) AND 1,2,4,5-TETRACYANOBENZENE (TCNB)

{2,2'-bis-1,3-dithiole-1,2,4,5-tetracyanobenzene), (TTF-TCNB), C6H4S4-C10H2N4, M = 382.3, monoclinic, P2(1)/a, a = 9.194(3), b = 12.342(3), c = 7.426(2)angstrom, beta = 95.12(3)degrees, Z = 2, D(x) = 1.52 Mg m-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 0.51 mm-1, F(000) = 776, T = 293 K, final R = 0.039 for 1480 unique observed [F(o) > 4sigma(F(o)2)] reflections. The complex represents a member of the series of crystal structures of molecular complexes containing TTF as an electron donor and TCNB as an electron acceptor. The structure was solved by direct methods and has been refined by full matrix least-squares calculations. The constituent molecules are stacked alternatively in infinite columns along the c axis. The mean separation of the molecular planes, which are inclined at the angle of 4.4-degrees, is 3.48 angstrom. There are no unusually short intermolecular contacts. Bond lengths and angles in the component molecules agree with values for neutral species; also the infrared and Raman spectra indicate a very slight degree of ionicity.