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Fluorine-19 nuclear magnetic resonance is an analytical technique used to identify fluorine-containing compounds. 19F is one of the most important nuclei for NMR spectroscopy.〔H. Friebolin "Basic One- and Two-Dimensional NMR Spectroscopy", Wiley-VCH, Weinheim, 2011. ISBN 978-3-527-32782-9〕 ==Operational details== 19F has a nuclear spin of 1/2 and a high magnetogyric ratio, which means that this isotope is highly responsive to NMR measurements. Furthermore, 19F comprises 100% of naturally-occurring fluorine. Other NMR-active nuclei spin 1/2 that are monoisotopic (or nearly so) are 1H and 31P. Because of its favorable nuclear properties and high abundance, 19F NMR measurements are very fast, comparable with 1H NMR spectroscopy. Indeed the 19F nucleus is the second most receptive NMR nucleus, after the 1H nucleus. The 19F NMR chemical shift range is very wide, ranging from ''ca.'' 550 to -250 ppm, however the most commonly encountered signals arising from organofluorine compounds lie between ''ca.'' -50 to -70 ppm (for CF3 groups) to -200 to -220 ppm (for CH2F groups). The very wide spectral range can cause problems in recording spectra, such as poor data resolution and inaccurate integration. The reference compound for 19F is CFCl3, although in the past a number of other compounds have been used, including CF3COOH (-76 ppm w.r.t. CFCl3) and C6F6 (-163 ppm w.r.t CFCl3) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fluorine-19 nuclear magnetic resonance」の詳細全文を読む スポンサード リンク
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