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Molecular Recognition of Medium-size Lactones by Enclathration of Cholic Acid |
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| Authors: | Kazuki Sada Kazunori Nakano Kiyoshi Hirayama Mikiji Miyata Satoshi Sasaki Kiichi Takemoto |
| Institution: | 1. Department of Chemistry, Faculty of Engineering , Gifu University , 1-1 Yanagido Gifu, 501-1112, Japan;2. Department of Applied Chemistry and Applied Fine Chemistry, Faculty of Engineering , Osaka University , Yamadaoka, Suita, Osaka, 565-0871, Japan;3. Nagoya Municipal Industrial Research Institute , Rokuban, Atsuta-ku, Nagoya, 456-0058, Japan;4. Department of Chemistry, Faculty of Engineering , Gifu University , 1-1 Yanagido Gifu, 501-1112, Japan;5. Department of Material and Life Science , Graduate School of Engineering, Osaka University , Yamadaoka, Suita, Osaka, 565-0871, Japan;6. Department of Applied Chemistry and Applied Fine Chemistry, Faculty of Engineering , Osaka University , Yamadaoka, Suita, Osaka, 565-0871, Japan |
| Abstract: | Abstract Molecular recognitions of medium size lactones by enclathration of cholic acid (CA) are described. Size and location of the substituents on the lactone rings play an important role for enclathration. Lactones within the limited steric dimensions are included in CA, and larger or smaller ones are not included to give guest-free crystals of CA. Moreover, CA partially separates one enantiomer from racemic lactones by recystallization. X-ray crystallographic studies reveal that all included lactones form the β-trans type bilayer structure having a pentagonal void channel with a side pocket. The cross-sections illustrate that the lactone rings are incorporated in the center of the channel and that the substituents of the guests are fixed in the side pockets. The asymmetric channel enables CA to discriminate size and chirality of medium size lactones. |
| Keywords: | Molecular recognition Enclathration Cholic acid Lactone Host-guest Crystal structures |