STRUCTURE AND PACKING ARRANGEMENT OF MOLECULAR COMPOUNDS. IX. 7,7,8,8-TETRACYANOQUINODIMETHANE-7,8-BENZOQUINOLINE (1:1)

Article abstract of DOI:10.1107/S0567740880007960

Crystals of the title compound, C12H4N4*C13H9N, are monoclinic, P2₁, with two units of the complex in a unit cell having a = 7.803(1), b = 18.878(2), c = 6.883(1) Angstroem and β = 100.55(2) deg.The structure was solved from three-dimensional precession diffractometer data by using Patterson search methods, and was refined to a conventional R = 0.056 and weighted r = 0.044.Almost parallel TCNQ and 7,8-benzoquinoline molecules are alternately stacked along the c axis.The layer-like arrangement of the complex is compared with that found in the (1:1) TCNQ:o-phenanthroline crystalline molecular compound .The differences between the packing modes of two closely related compounds appear to be due mainly to a different relative contribution of the dipole-dipole interaction to the stabilization of the structures.A rigid-body anisotropic constrained refinement was carried out which converged to R = 0.061 and weighted r = 0.051.The results of the constrained refinement along with results of energy-profile calculations indicate that the (large) thermal parameters of 7,8-benzoquinoline describe genuine motion, unlike those of the related o-phenanthroline in the above-mentioned structure.