Structural aspects of oligothienyl series from X-ray powder diffraction data

The structures of the series of oligothienyls (T4-T5-T6) have been determined and refined from X-ray powder diffraction data using the Rietveld full-profile analysis. Unlike polythiophene, all the molecules in the isomorphous series display no internal symmetry, being only approximately planar within 12 degrees. Packing is always achieved through a common molecular disposition, which is usually defined as a herringbone arrangement, with an angle between mean planes of adjacent molecules which spans from 60 degrees to 70 degrees.