Deuterium NMR is
NMR spectroscopy
Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique based on re-orientation of atomic nuclei with non-zero nuclear spins in an external magnetic f ...
of
deuterium
Deuterium (hydrogen-2, symbol H or D, also known as heavy hydrogen) is one of two stable isotopes of hydrogen; the other is protium, or hydrogen-1, H. The deuterium nucleus (deuteron) contains one proton and one neutron, whereas the far more c ...
(H or D), an
isotope
Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...
of
hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
.
[
]
Deuterium is an isotope with
spin = 1, unlike hydrogen-1, which has spin = 1/2. The term deuteron NMR, in direct analogy to proton NMR, is also used.
[Spiess, H. W. (1985). "Deuteron NMR – A new Tool for Studying Chain Mobility and Orientation in Polymers", ''Advances in Polymer Science'' 66: 23-57. DOI: 10.1007/3-540-13779-3_16.] Deuterium NMR has a range of
chemical shift
In nuclear magnetic resonance (NMR) spectroscopy, the chemical shift is the resonant frequency of an atomic nucleus relative to a standard in a magnetic field. Often the position and number of chemical shifts are diagnostic of the structure of ...
similar to
proton NMR but with poor resolution, due to the smaller magnitude of the magnetic dipole moment of the deuteron relative to the proton. It may be used to verify the effectiveness of deuteration: a deuterated compound will show a strong peak in H NMR but not proton NMR.
H NMR spectra are especially informative in the solid state because of its relatively small quadrupole moment in comparison with those of bigger quadrupolar nuclei such as chlorine-35. This allows for the whole spectrum to be excited with practically achievable pulses of a few microseconds in duration. However, since the natural abundance of H is only 0.016%, the sample must usually be H-enriched to achieve a strong enough signal. For a given C-D moiety, the quadrupolar splitting in the H NMR spectrum depends in a simple way on the angle between the C-D bond and the applied static magnetic field.
Thus, H NMR can probe orientation distributions in partially ordered deuterated polymers.
Changes in C-D bond orientation due to molecular motions have pronounced effects on the spectral line shape.
One example is the use of H NMR to study lipid membrane phase behavior.
References
External links
Articles about solid-state deuterium NMR
Nuclear magnetic resonance
NMR
Nuclear magnetic resonance (NMR) is a physical phenomenon in which atomic nucleus, nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near and far field, near field) and respond by producing ...
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