Helical Inversion of Gel Fibrils by Elongation of Perfluoroalkyl Chains as Studied by Vibrational Circular Dichroism |
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Authors: | Hisako Sato Tomoko Yajima Akihiko Yamagishi |
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Institution: | 1. Graduated of Science and Engineering, Ehime University, Matsuyama, Japan;2. Department of Chemistry, Ochanomizu University, Tokyo, Japan;3. Department of Chemistry, Toho University, Chiba, Japan |
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Abstract: | Vibrational circular dichroism (VCD) spectroscopy was applied to gelation by a chiral low‐molecular mass weight gelator, N,N’‐diperfluoroalkanoyl‐1,2‐trans‐diaminocyclohexane. Attention was focused on the winding effects of (–CF2)n chains on the gelating ability. For this purpose, a series of gelators were synthesized with perfluoroalkyl chains of different length (n = 6–8). When gelation was studied using acetonitrile as a solvent, the fibrils took different morphologies, depending on the chain length: twisted saddle‐like ribbon or helical ribbon from fibril (n = 6) and a helical ribbon from platelet (n = 8). The signs of VCD peaks assigned to the couplet of C=O stretching and to the C‐F stretching were also dependent on n, indicating that a gelator molecule changed conformation on elongating perfluoroalkyl chains. A model is proposed for the aggregation modes in fibrils. Chirality 28:361–364, 2016. © 2016 Wiley Periodicals, Inc. |
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Keywords: | vibrational circular dichroism supramolecular chiral gelator perfluoroalkyl chains |
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