AbstractsChemistry

The crystal structures of a series of semiconducting sulfur-hetero benzo[ k ]fluoranthene derivatives, differing from each other in the position of a methoxyl group on a phenyl ring, were studied with electron diffraction and X-ray diffraction methods. All three compounds crystallized in the orthorhombic system. The unit cell parameters are a = 5.24(1) Å, b = 28.80(3) Å, and c = 45.21(5) Å for the non-substituted compound, a = 5.087(5) Å, b = 15.80(2) Å, and c = 45.64(6) Å for the ortho -substituted compound, and a = 10.35(2) Å, b = 32.58(7) Å, and c = 25.25(6) Å for the para -substituted compound.An interdigitating model is proposed to be the molecular packing scheme in the crystals of all three compounds, based on the analysis of diffraction intensities. The frequently observed interlayer displacements in the crystals of the para -substituted compound, which were rarely found in the other two compounds, are attributed to the disturbance of the interdigitating packing of molecules by the protruding para -methoxyl group.