title: A doubly alkynylpyrene-threaded [4]rotaxane that exhibits strong circularly polarized luminescence from the spatially restricted excimer.
abstract: The Sonogashira coupling of γ-CD-encapsulated alkynylpyrenes with terphenyl-type stopper molecules gave a doubly alkynylpyrene-threaded [4]rotaxane. The rotaxane showed only excimer emission, with a high fluorescence quantum yield of Φf =0.37, arising from the spatially restricted excimer within the cavity of the γ-CD. The excimer emission suffered little from self-quenching up to a concentration of 1.5×10(-5)  M and was circularly polarized with a high glum  value of -1.5×10(-2) . The strong circularly polarized luminescence may result from the two stacked pyrenes existing in the rotaxane in an asymmetrically twisted manner.
authors.affiliation: Graduate School of Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan) http://www.pha.u-toyama.ac.jp/yakka/index-j.html. inouye@pha.u-toyama.ac.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Inouye
authors.forename: Koichiro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yonenaga
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Itou
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Taka-aki
authors.initials: TA
authors.lastname: Uchida
authors.forename: Munetaka
authors.initials: M
authors.lastname: Iwamura
authors.forename: Koichi
authors.initials: K
authors.lastname: Nozaki
mesh_terms: D002942:Circular Dichroism; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry; D009010:Monte Carlo Method; D011721:Pyrenes / Q000737:chemistry*; D043862:Rotaxanes / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D047408:gamma-Cyclodextrins / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D011721:Pyrenes; D043862:Rotaxanes; D047408:gamma-Cyclodextrins; C023792:gamma-cyclodextrin
keywords: chirality; circularly polarized luminescence; cyclodextrins; excimer emission; rotaxanes