No-D NMR (No-Deuterium Proton NMR) technique is a measurement of high resolution 1H NMR spectra without deuterium solvent. It suggests that any reaction mixture or reagent solution are directly available for No-D NMR measurement. In conventional NMR measurements, 2H signals of deuterium solvent are used for the shimming, however 1H solvent signals are as well in No-D NMR measurements. Since suppression of strong 1H solvent signals by WET eliminates 13C satellite signals also, it is convenient approach to collect 1H NMR spectra without deuterium solvent by No-D NMR measurement.
Merits of No-D NMR
"No-D NMR" is your solution!
- ● The better approach for unstable compound just after chemical reactions
- ● Skipping the laborious sample preparation (dissolving into a deuterated solvent after sample purification)
- ● Cost reduction for deuterated solvent in daily NMR measurement work
Automation script for No-D NMR
The following 5 steps are automated No-D NMR measurement procedure on NMR software Delta, and every tedious measurement parameters are automatically adjusted.
- ① Shimming
- ② Detecting solvent signals
- ③ Suppression of solvent signals
- ④ Processing FID data
- ⑤ Chemical shift adjustment
On Delta software, chemical shift in the conventional 1H measurement is not adjusted without NMR lock (Fig. 1a), but the automation of No-D NMR adjusts chemical shift automatically (Fig. 1b). Its result has the same chemical shift information as deuterated solvent sample spectrum (Fig. 1c).
Fig.1 1H spectra of 5 mg rotenone measured with JNM-ECZ500R
- Select solvent
- Input the number of suppression signals
Fig.2 Operation window of No-D NMR (Delta V5)
Application of No-D NMR 1: Observation of exchangeable 1H signals
When the compound with exchangeable proton is dissolved in exchangeable proton solvent (D2O, CD3OD, and etc.), proton atom is replaced with deuterium atom. As results, it is not possible to observe amino protons for the target molecule (Fig. 3 upper). On the other hand, the exchangeable proton can be observed in No-D NMR, since amino protons are kept under protonated solvent (Fig. 3 bottom).
Fig.3 2.5mg L-Tryptophan measured with JNM-ECZ600R
Application of No-D NMR 2: Apply to mixed solvent
Because No-D NMR can suppress multi site signals, it is also effective for multi signal solvents such as CH3OH and mixed solvent sample.
Furthermore, 13C decoupling is useful, when solvent 13C satellite signal overlap with sample signal. Fig.5 indicates how sample signal can be distinguished from 13C satellite by 13C decoupling. Chemical shifts in Fig.4 and Fig.5 are intentionally adjusted for better clarity.
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