Dipolar Quinoidal Acene Analogues as Stable Isoelectronic Structures of Pentacene and Nonacene

Abstract

Abstract Quinoidal thia‐acene analogues, as the respective isoelectronic structures of pentacene and nonacene, were synthesized and an unusual 1,2‐sulfur migration was observed during the Friedel–Crafts alkylation reaction. The analogues 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 stable because of the existence of more aromatic sextet rings, a dipolar character, and kinetic blocking. They exhibit unique packing in single crystals resulting from balanced dipole–dipole and [CH⋅⋅⋅π]/[CH⋅⋅⋅S] interactions.