Crystal structure of the 1 : 1 molecular complex of chrysene and tetrafluoro-p-benzoquinone (fluoranil)

Abstract

The crystal and molecular structure of the title complex has been determined by three-dimensional X-ray diffraction methods. Crystals are monoclinic, a= 6.645, b= 7.047, c= 19.363 Å, β= 106.6°, space group P2₁/c, Z= 2. The structure was determined from 1 078 diffractometer data by Patterson and Fourier methods, and refined by least-squares methods to R 0.070. In the crystals, alternate planar chrysene and fluoranil molecules form stacks along the b axis. The mean separation of the molecular planes is 3.23 Å and the interplanar angle is 0.7°. The interplanar spacing is the same as in perylene–fluoranil, and is not solely determined by charge-transfer interactions, although the relative orientation of the two molecules favours such interactions as well as dipole–induced-dipole forces. There are no abnormally short contacts between the stacks, and the lattice structure is related to the poor photoconductivity of the complex. The dimensions of both molecules are in good agreement with known values.