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Author Topic: Absolute referencing of NMR spectra  (Read 8312 times)

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wildfyr

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Re: Absolute referencing of NMR spectra
« Reply #15 on: September 13, 2017, 03:05:56 AM »

I recently had a Discussion about 19F NMR referencing with a fellow PhD student. Apparantly, it's a pain if you want to be able to compare different measurements or use it in a similar way to chemical shifts in 1H or 13C NMR. As far as I know, the shifts are also extremly solvent dependent. Bottom line what I would do: just describe what you have done and how or if you referenced your spectra. Then wait until someone figures out something meaningful and practically doable.

I didnt know this effect was so powerful. I guess thats why people run the spectrum in CFCl3 when they need to reference. Since its the solvent, it will have a stable shift due it its very high concentration.
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Flatbutterfly

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Re: Absolute referencing of NMR spectra
« Reply #16 on: September 15, 2017, 06:49:36 AM »

The reference compound for 19F is CFCl3,[3] 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).
https://en.wikipedia.org/wiki/Fluorine-19_nuclear_magnetic_resonance
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Irlanur

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Re: Absolute referencing of NMR spectra
« Reply #17 on: April 27, 2018, 05:57:21 AM »

In case some of you would like to properly reference fluorine-NMR, there is now a nice paper out: https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201802620
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