title: Fluorinated and trifluoromethylated corannulenes.
abstract: The syntheses and properties of corannulenes carrying electron-withdrawing groups (F, CF3 , C6 F5 ) are reported. Direct fluorination of corannulene (C20 H10 ) was carried out with xenon difluoride, and the crystal structure of the product was confirmed by the X-ray analysis. Novel trifluoromethylated corannulenes, including the versatile 4,9-dibromo-1,2-bis(trifluoromethyl)corannulene, were obtained by various established ring-closing reactions. Besides the use of hexafluorobutyne for the construction of fluoranthenes by Diels-Alder reaction as precursor molecules to form 1,2-disubstituted corannulenes, bis(pentafluorophenyl)acetylene was employed as dienophile. The molecular structure and crystal packing of a trifluoromethylated corannulene was determined by single-crystal X-ray analysis and compared with those known brominated and trifluoromethylated corannulenes. The general electron-acceptor properties of corannulenes bearing substituents introduced in particular positions by liquid-phase synthesis are discussed together with published computational results.
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Fabeckstrasse 34-36, 14195 Berlin (Germany); Institute for Molecular Science, Myodaiji, Okazaki 444-8787 (Japan).
authors.forename: Bernd M
authors.initials: BM
authors.lastname: Schmidt
authors.forename: Berit
authors.initials: B
authors.lastname: Topolinski
authors.forename: Mihoko
authors.initials: M
authors.lastname: Yamada
authors.forename: Shuhei
authors.initials: S
authors.lastname: Higashibayashi
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Shionoya
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Sakurai
authors.forename: Dieter
authors.initials: D
authors.lastname: Lentz
keywords: corannulenes; electrochemistry; fluorine; stacking interactions; trifluoromethylation