In a recent article published in Angew. Chem. Int. Ed., 2015, 54, 14412 (Link ), Dr. Chi and her co-workers synthesized quinoidal thia- acene analogues as the respective isoelectronic structures of pentacene and nonacene and an unusual 1,2-sulfur migration was observed during the Friedel-Crafts alkylation reaction. They display a closed-shell quinoidal structure in the ground state with a distinctive dipolar character. In contrast to their acene isoelectronic structures, both compounds are very stable because of existence of more aromatic sextet rings, dipolar character, and kinetic blocking. They exhibit unique packing in single crystals due to balanced dipole-dipole and [C-H•••π]/[C-H•••S] interactions.
