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A sample 19F NMR spectrum of a simple organic compound. Integrations are shown under each peak. 19F NMR spectrum of 1-bromo-3,4,5-trifluorobenzene. The expansion shows the spin–spin coupling pattern arising from the para-fluorine coupling to the 2 meta-fluorine and 2 ortho proton nuclei.
Fluorine-19 is NMR-active with a spin of 1/2+, so it is used in fluorine-19 NMR spectroscopy. Fluorine-20. Fluorine-20 is an unstable isotope of fluorine.
A database that was developed and maintained by the publisher John Wiley & Sons. This database included more than 700,000 NMR, IR and MS Spectra, statistics specific to the NMR spectra are not listed. The NMR data includes 1 H, 13 C, 11 B, 15 N, 17 O, 19 F, 29 Si, and 31 P. The data were in the form of graphically displayed line lists.
The database contains also a smaller amount of NMR data from carbohydrates, cofactors and ligands. [1] These data are crossreferenced to 3D structures in the PDB when available. The NMR data are provided in the NMR-STAR file format and a number of format conversion tools are available at the site to convert files from NMR-STAR to other formats. [1]
If a spectrum of an unknown chemical compound is available, a reverse search can be carried out by entering the values of the chemical shift, frequency or mass of the peaks in the NMR, FT-IR or EI-MS spectrum respectively. This type of search affords all the chemical compounds in the database that have the entered spectral characteristics. [6]
The typical impurity in triflic anhydride is triflic acid, which is also a colorless liquid. Samples of triflic anhydride can be assayed by 19 F NMR spectroscopy: −72.6 ppm [8] vs. −77.3 for TfOH (std CFCl 3).
Hexafluorobenzene has been used as a reporter molecule to investigate tissue oxygenation in vivo. It is exceedingly hydrophobic, but exhibits high gas solubility with ideal liquid gas interactions. Since molecular oxygen is paramagnetic it causes 19 F NMR spin lattice relaxation (R1): specifically a linear dependence R1= a + bpO 2 has been ...
NMR database (NMR = nuclear magnetic resonance) may refer to: Nuclear magnetic resonance spectra database, a collection of NMR spectra for a large number of compounds; Nuclear magnetic resonance database method, a strategy to identify the stereochemistry of certain chiral compounds