title: Twisted Polycyclic Arenes from Tetranaphthyldiphenylbenzenes by Controlling the Scholl Reaction with Substituents.
abstract: Herein, we report two new types of twisted polycyclic arenes (2 a, b and 3 a, b) with constitutionally isomeric π-backbones, which are synthesized by controlling the Scholl reaction of 1,2,4,5-tetra(naphth-2-yl)-3,6-diphenylbenzene (1) with properly positioned electron-donating substituents. With a polycyclic backbone containing two [5]helicene and four [4]helicene moieties, 2 a and b are new members of multiple helicenes with interesting stereochemistries. The as-synthesized 2 a and b are the twisted isomers, and thermal isomerization of twisted-2 b results in anti-2 b, a more stable stereoisomer. Both twisted- and anti-2 b have been fully characterized, and the thermal isomerization of twisted-2 b has been studied with1H NMR spectroscopy and DFT calculations. Compounds 3 a and b are new members of twistacenes, the benzannulated pentacene backbone of which exhibits an end-to-end twist as found from the crystal structure. Twisted- and anti-2 b are also found to function as p-type semiconductors in solution-processed thin film transistors, whereas the thin films of 3 b appear insulating presumably due to the lack of π-π interactions.
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, P.R. China.
authors.forename: Luyan
authors.initials: L
authors.lastname: Yuan
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, P.R. China.
authors.forename: Bowen
authors.initials: B
authors.lastname: Shan
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, P.R. China.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, P.R. China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Miao
keywords: arenes; organic semiconductors; oxidative cyclodehydrogenation; polycycles; regioselectivity