[Question from NMRWiki Q&A forum] Extraneous Peaks Observed on 19F NMR of Isolated "Pure" Compound
Extraneous Peaks Observed on 19F NMR of Isolated "Pure" Compound
I am observing four extraneous peaks on 19F, each at around 0.5% of the main signal at +11Hz, +88Hz, -17Hz, and -185Hz (+ is downfield) away from the main signal. Due to legal issues, I am not able to divulge the structure of the main compound, but can tell you that the fluorine signal comes from three isochronous benzylic flourines (i.e. a (trifluoromethyl)benzene constituent of a larger compound isolated as a salt). These four peaks do not appear to be impurity related since chiral and achiral HPLC methods reveal the...
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10-04-2011 08:47 PM
[NMR paper] Improved pulse sequences for pure exchange solid-state NMR spectroscopy.
Improved pulse sequences for pure exchange solid-state NMR spectroscopy.
Related Articles Improved pulse sequences for pure exchange solid-state NMR spectroscopy.
Magn Reson Chem. 2004 Feb;42(2):285-90
Authors: Vosegaard T, Nielsen NC
Spin-exchange experiments are useful for improving the resolution and establishment of sequential assignments in solid-state NMR spectra of uniformly (15)N-labeled proteins oriented macroscopically in phospholipid bilayers. To exploit this advantage fully, it is crucial that the diagonal peaks in the...
what is/ how do you calculate the chemical shift in an NMR?
I have read the technical definitions but I still do not understand what the chemical shift means and how you calculate it given an NMR peak. If someone could kind of dumb it down for me but still give me the important things to know/ how it helps you determine the structure of a molecule with the NMR I would appreciate it.
1H Pure shift
Linear Mode
