A Doubly Alkynylpyrene‐Threaded [4]Rotaxane That Exhibits Strong Circularly Polarized Luminescence from the Spatially Restricted Excimer |
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| Authors: | Prof. Dr. Masahiko Inouye Koichiro Hayashi Yuki Yonenaga Dr. Tatsuya Itou Dr. Kazuhisa Fujimoto Taka‐aki Uchida Dr. Munetaka Iwamura Prof. Dr. Koichi Nozaki |
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| Affiliation: | 1. Graduate School of Pharmaceutical Sciences, University of Toyama, Toyama 930‐0194 (Japan) http://www.pha.u‐toyama.ac.jp/yakka/index‐j.html;2. Department of Applied Chemistry and Biochemistry, Kyushu Sangyo University, Fukuoka 813‐8503 (Japan);3. Graduate School of Science and Engineering, University of Toyama, Toyama 930‐8555 (Japan) |
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| 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. |
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| Keywords: | chirality circularly polarized luminescence cyclodextrins excimer emission rotaxanes |
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