March 28, 2024, 10:45:08 AM
Forum Rules: Read This Before Posting


Topic: Absolute referencing of NMR spectra  (Read 16552 times)

0 Members and 1 Guest are viewing this topic.

Offline wildfyr

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 1771
  • Mole Snacks: +203/-10
Re: Absolute referencing of NMR spectra
« Reply #15 on: September 13, 2017, 09:05:56 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.

Offline Flatbutterfly

  • Regular Member
  • ***
  • Posts: 57
  • Mole Snacks: +7/-0
Re: Absolute referencing of NMR spectra
« Reply #16 on: September 15, 2017, 12:49:36 PM »
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

Offline Irlanur

  • Chemist
  • Full Member
  • *
  • Posts: 423
  • Mole Snacks: +32/-4
Re: Absolute referencing of NMR spectra
« Reply #17 on: April 27, 2018, 11:57:21 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

Sponsored Links