394697.fig.002
Figure 2: Gas phase MP2/6-311G** geometrical parameters of thiophene and 2,2′-bithiophene anti-gauche and syn-gauche rotamers. The experimental data reported in parentheses are taken from [47] (thiophene) and [9] (2,2′-bithiophene). The MP2/6-311G** (experimental) S–C2–C2’–S dihedral angles are 137° (148°, see [9]) and 48° for the anti-gauche and syn-gauche conformation, respectively.