title: Unexpected Scholl Reaction of 6,7,13,14-Tetraarylbenzo[k]tetraphene: Selective Formation of Five-Membered Rings in Polycyclic Aromatic Hydrocarbons.
abstract: Cyclodehydrogenation is a versatile reaction that has enabled the syntheses of numerous polycyclic aromatic hydrocarbons (PAHs). We now describe a unique Scholl reaction of 6,7,13,14-tetraarylbenzo[k]tetraphene, which "unexpectedly" forms five-membered rings accompanying highly selective 1,2-shift of aryl groups. The geometric and optoelectronic nature of the resulting bistetracene analogue with five-membered rings is comprehensively investigated by single-crystal X-ray, NMR, UV-vis absorption, and cyclic voltammetry analyses. Furthermore, a possible mechanism is proposed to account for the selective five-membered-ring formation with the rearrangement of the aryl groups, which can be rationalized by density functional theory (DFT) calculations. The theoretical results suggest that the formation of the bistetracene analogue with five-membered rings is kinetically controlled while an "expected" product with six-membered rings is thermodynamically more favored. These experimental and theoretical results provide further insights into the still controversial mechanism of the Scholl reaction as well as open up an unprecedented entry to extend the variety of PAHs by programing otherwise unpredictable rearrangements during the Scholl reaction.
authors: Max-Planck Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors: Junzhi
authors: J
authors: Liu
authors: Max-Planck Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors: Akimitsu
authors: A
authors: Narita
authors: Laboratory for Chemistry of Novel Materials, University of Mons , Place du Parc 20, B-7000 Mons, Belgium.
authors: Silvio
authors: S
authors: Osella
authors: Max-Planck Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors: Wen
authors: W
authors: Zhang
authors: Institut für Organische Chemie, Universität Mainz , Düsbergweg 10-14, 55099 Mainz, Germany.
authors: Dieter
authors: D
authors: Schollmeyer
authors: Laboratory for Chemistry of Novel Materials, University of Mons , Place du Parc 20, B-7000 Mons, Belgium.
authors: David
authors: D
authors: Beljonne
authors: Center for Advancing Electronics Dresden (CFAED) & Department of Chemistry and Food Chemistry, Technische Universität Dresden , 01062 Dresden, Germany.
authors: Xinliang
authors: X
authors: Feng
authors: Max-Planck Institut für Polymerforschung , Ackermannweg 10, 55128 Mainz, Germany.
authors: Klaus
authors: K
authors: Müllen