1,6-Bis(4-methoxyphenylsulfanyl) perchlorofluoranthene: A molecule with sandwiched π–π stacking linked by a flexible five-membered ring

1,6-Bis(4-methoxyphenylsulfanyl) perchlorofluoranthene, a molecule with a dramatic orientation effect due to intramolecular aromatic π–π interactions (APPI), was synthesized and characterized using X-ray diffraction, DFT calculations, UV–vis absorption spectra, and excitation spectra. The crystals are monoclinic, space group P2(1)/n with a = 7.9707(10), b = 18.349(2), c = 20.649(3) Å, β = 95.259(3)°, V = 3007.3(7) Å3 and Z = 4. The flexibility of the five-membered ring in the molecule was shown to facilitate the intramolecular APPI formation.