Navigationsweiche Anfang

Navigationsweiche Ende

Select language

Standard NMR Experiments

           1D Experiments                                                2D Experiments

NMR Frequencies:
A complete list of the NMR frequencies of all nuclei with spin > 0 together with information on their availability at Wuppertal is given here (pdf).

Detailed information on frequencies, standard und referencing is available from the IUPAC recommendations (2008).

Frequencies (BF) [MHz]

NucleusAVANCE 400AVANCE 600 Reference
19F376.498534 - CFCl3

For all 13C-Experiments the concentration should be as high as possible.

In order to avoid useless 13C experiments the quality of the samples is verified by the signal-to-noise ratio of the 1H spectrum. If certain conditions are not fulfilled the 13C experiment is automatically cancelled on weekdays. Samples with low concentrations should be planned for the weekend.

Reference: 13C spectra are automatically referenced to the 13C shift of the deuterated solvent as long as the signal pattern is not disturbed too much.

13C Chemical Shifts of Deuterated Solvents
Solventδ [ppm]   Solventδ [ppm]  Solventδ [ppm]  Solventδ [ppm]  
Acetone-d6 30.50 Acetonitrile-d3  1.28 Benzene-d6128.00 Chloroform-d1 77.00
Dimethylformamide-d6 30.10 Dimethylsulfoxide-d6 39.50 Dioxane-d8 66.30 Acetic acid-d4 20.00
Ethanol-d6 17.20 Methanol-d4 49.00 Methylenchloride-d2 53.73 Pyridine-d5123.50
Tetrachloroethane-d2 74.20 Tetrahydrofurane-d8 25.20 Toluene-d8 20.42 Water-d2 -

A comprehensive list of 1H and 13C chemical shifts of numerous impurities (c.f. H2O) in the common solvents is available in Organometallics 2010, 29, 2176–2179.

Standard experiments usually consist of combined series of interdependent spectra, for example
      1H (PROTON) - 13C (C13CPD) - 13C (C13DEPT135p)
The proton spectrum determines the number of scans (NS) of the 13C spectrum (256, 1024 or abortion). The phase of the DEPT spectrum as well as the referencing (SR) is transferred from the preceding 13C spectrum.

Optimization of the Spectral Width SW
In case of 1D spectra, e.g. 19F  or 31P spectra, a special option may be selected: A survey spectrum is recorde with reduced number of scans. Depending on the quality of the spectrum (signal-to noise ratio) the measurement is either

(a) aborted,
(b) redorded with the unchanged sweep width with a scan number increased by a factor of 4  or
(c) the spectral width (SW) is optimiized and the scan number NS is retained or decreased by a factor of 4, depending on the quality of the survey spectrum.

The additional experiments are saved with the following experiment numbers (expno):
1H +1000
13C +2000
19F +3000
31P +4000
       Other +5000

For 19F spectra (AVANCE 400 only), there is a special sequence consisting of
   (a)  19F survey spectrum,
   (b)  Sweep optimized 19F detail spectrum,
   (c)  1H decoupled 19F spectrum with the parameters taken from (b),
   (d)  19F decoupled 1H spectrum with the decoupler set to the center frequency (O1) from (b)
   (e)  regular 1H spectrum.