Nuclear magnetic resonance spectroscopy decoupling

B.A. Berkowitz, J.J.H. Ackerman, Proton decoupled fluorine nuclear-magnetic-resonance spectroscopy in situ, Biophys. J. 51 (1987) 681-685. 

Fig. 3.73 Decoupled spectrum of crotonaldehyde. Data reproduced from W. McFarlane and R. F. M. White (1972). Techniques of High Resolution Nuclear Magnetic Resonance Spectroscopy. London Butterworths, p. 28.

Nuclear magnetic resonance spectroscopy has emerged as the most powerful tool for elucidating the molecular structures of cyclophos-phazene derivatives in solution. Proton NMR spectroscopy has been widely used because of its easy accessibility. The recent development of sophisticated instrumental facilities and the application of broadband proton decoupling have greatly improved the quality and usefulness of the 31P spectra (252) of cyclophosphazenes, and it is likely that this technique will become increasingly popular in the future. Fluorine NMR studies are useful for deducing the structures of fluorocyclophosphazenes, and the potential of this technique has been demonstrated in recent years (209, 210, 213, 307, 308, 343). 

J. B. Grutzner and R. E. Santini, "Coherent broad-band decoupling — an alternative to proton noise decoupling in carbon-13 nuclear magnetic resonance spectroscopy, J. Magn. Resonance 19, 173-187 (1971). 

Levitt M, Freeman R and Frenkiel T (1983) Broadband decoupling in high-resolution nuclear magnetic resonance spectroscopy. In Waugh JS (ed) Advances in Magnetic Resonance, Vol 11, pp 48-110. New York Academic Press. 

Figure 6 The H-decoupled NMR spectrum of (A) control rat urine and urine collected for 24 h following administration of (B) 10 or (C) 30 mg kg- [1,2,3- C]acrylonitrile. Signals are labelled according to metabolite number (see Figure 8, and the letter of carbon-derived form acrylonitrile (aCH2=bCH2-cCN). Reprinted with permission from Fennell TR, Kedderis GL and Sumner SC (1991) Urinary metabolites of [1,2,3- 3C]acrylonitrile in rats and mice detected by nuclear magnetic resonance spectroscopy. Chemical Research in Toxicology 678-687. Copyright 1991, American Chemical Society.

E. Vinogradov. P. K. Madhu and S. Vega, Proton spectroscopy in solid state nuclear magnetic resonance with windowed phase modulated Lee-Goldburg decoupling sequences. Chem. Phys. Lett., 2002, 354, 193-202. 

One of the most useful proton nuclear magnetic resonance ( H-NMR) one-dimensional (a single-frequency axis) techniques to be applied in structure determination is difference spectroscopy. This approach involves subtracting a spectrum obtained under the conditions of some perturbation from a normal, unperturbed spectrum. The resulting difference spectrum reveals the spectral changes caused by the perturbation, whereas those signals that remain unaffected are nulled. The perturbation can be a decoupling irradiation, a nuclear Overhauser enhancement, or even a population transfer experiment (135, 328). 

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