title: Dipolar Quinoidal Acene Analogues as Stable Isoelectronic Structures of Pentacene and Nonacene.
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.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 (Singapore).
authors.forename: Xueliang
authors.initials: X
authors.lastname: Shi
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 (Singapore).
authors.forename: Weixiang
authors.initials: W
authors.lastname: Kueh
authors.affiliation: KAUST Catalysis Center and Division of Physical Sciences & Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia).
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.affiliation: KAUST Catalysis Center and Division of Physical Sciences & Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia).
authors.forename: Kuo-Wei
authors.initials: KW
authors.lastname: Huang
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 (Singapore). chmcc@nus.edu.sg.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Chi
keywords: X-ray diffraction; aromaticity; density functional calculations; polycyclic aromatic hydrocarbons; structure determination