High-pressure NMR study of cis-1,n-disubstituted[n]paracyclophanes. Effect of increased pressure on the hindered internal rotation. |
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| Authors: | H Yamada S Yonehara S Tanaka F Muro A Watanabe K Nishikawa |
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| Institution: | Contribution from the Department of Chemistry, Faculty of Science, Kobe University, Nada-ku, Kobe 657-8501, Japan. shichijo@biol.kobe-u.ac.jp |
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| Abstract: | The effect of hydrostatic pressure on the rate of internal rotation of title compounds has been examined by the DNMR method. Quartz pressure-resisting NMR cells were used to realize the high-pressure experiments up to 390 (line shape measurements) and 450 MPa (chemical shift measurements). Application of hydrostatic pressure was found to accelerate the rotation of the benzene ring, while pressure-induced low-frequency chemical shifts of bridge methylene protons indicated that there is a considerable shrinkage of the methylene bridge structure upon pressurization. |
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