scholarly journals Chemical Reaction Monitoring Using Zero-Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

2020 ◽  
Author(s):  
Dudari B. Burueva ◽  
James Eills ◽  
John W. Blanchard ◽  
Antoine Garcon ◽  
Román Picazo Frutos ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Susceptibility ◽  
Magnetic Resonance ◽  
Low Frequency ◽  
Hydrogen Gas ◽  
Zero Field ◽  
Sample Container ◽  
Electrically Conductive ◽  
Titanium Tube ◽  
Nuclear Magnetic

<div> <p>We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero-field nuclear magnetic resonance. This is possible because magnetic susceptibility broadening is insignificant at ultralow magnetic fields. We show the two-step hydrogenation of dimethyl acetylenedicarboxylate with <i>para</i>-enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero-field NMR signals ensure that there is no significant signal attenuation due to shielding by the electrically conductive sample container. This method paves the way for <i>in situ</i> monitoring of reactions in complex heterogeneous multiphase systems and in reactors made from conductive materials without magnetic susceptibility induced line broadening.</p></div>

scholarly journals Chemical Reaction Monitoring Using Zero-Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

2020 ◽  
Author(s):  
Dudari B. Burueva ◽  
James Eills ◽  
John W. Blanchard ◽  
Antoine Garcon ◽  
Román Picazo Frutos ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Susceptibility ◽  
Magnetic Resonance ◽  
Low Frequency ◽  
Hydrogen Gas ◽  
Zero Field ◽  
Sample Container ◽  
Electrically Conductive ◽  
Titanium Tube ◽  
Nuclear Magnetic

<div> <p>We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero-field nuclear magnetic resonance. This is possible because magnetic susceptibility broadening is insignificant at ultralow magnetic fields. We show the two-step hydrogenation of dimethyl acetylenedicarboxylate with <i>para</i>-enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero-field NMR signals ensure that there is no significant signal attenuation due to shielding by the electrically conductive sample container. This method paves the way for <i>in situ</i> monitoring of reactions in complex heterogeneous multiphase systems and in reactors made from conductive materials without magnetic susceptibility induced line broadening.</p></div>

scholarly journals Polarization Transfer via Field Sweeping in Parahydrogen-Enhanced Nuclear Magnetic Resonance

2019 ◽  
Author(s):  
James Eills ◽  
John W. Blanchard ◽  
Teng Wu ◽  
Christian Bengs ◽  
Julia Hollenbach ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Maleic Acid ◽  
Hydrogen Gas ◽  
Zero Field ◽  
Field Sweep ◽  
The Magnetic Field ◽  
Proton Singlet ◽  
Nuclear Magnetic

<div><br></div><div><table><tr><td>We show that in a spin system of two magnetically inequivalent protons coupled to a heteronucleus such as 13C, an adiabatic magnetic field sweep, passing through zero field, transfers proton singlet order into magnetization of the coupled heteronucleus. This effect is potentially useful in parahydrogen-enhanced nuclear magnetic resonance, and is demonstrated on singlet-hyperpolarized [1-13C]maleic acid, which is prepared via the reaction between [1-13C]acetylene dicarboxylic acid and para-enriched hydrogen gas. The magnetic field sweeps are of microtesla amplitudes, and have durations on the order of seconds. We show a polarization enhancement by a factor of 10<sup>4</sup> in the 13C spectra of [1-13C]maleic acid in a 1.4 T magnetic field.</td></tr></table></div>

scholarly journals Polarization Transfer via Field Sweeping in Parahydrogen-Enhanced Nuclear Magnetic Resonance

2019 ◽  
Author(s):  
James Eills ◽  
John W. Blanchard ◽  
Teng Wu ◽  
Christian Bengs ◽  
Julia Hollenbach ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Maleic Acid ◽  
Hydrogen Gas ◽  
Zero Field ◽  
Field Sweep ◽  
The Magnetic Field ◽  
Proton Singlet ◽  
Nuclear Magnetic

<div><br></div><div><table><tr><td>We show that in a spin system of two magnetically inequivalent protons coupled to a heteronucleus such as 13C, an adiabatic magnetic field sweep, passing through zero field, transfers proton singlet order into magnetization of the coupled heteronucleus. This effect is potentially useful in parahydrogen-enhanced nuclear magnetic resonance, and is demonstrated on singlet-hyperpolarized [1-13C]maleic acid, which is prepared via the reaction between [1-13C]acetylene dicarboxylic acid and para-enriched hydrogen gas. The magnetic field sweeps are of microtesla amplitudes, and have durations on the order of seconds. We show a polarization enhancement by a factor of 10<sup>4</sup> in the 13C spectra of [1-13C]maleic acid in a 1.4 T magnetic field.</td></tr></table></div>

Nuclear Magnetic Resonance Studies of δ-Stabilized Plutonium

2003 ◽  
Vol 802 ◽  
Author(s):  
N. J. Curro ◽  
L. Morales
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Low Frequency ◽  
Lattice Relaxation ◽  
Spin Fluctuations ◽  
Spin Lattice Relaxation ◽  
Cubic Symmetry ◽  
Magnetic Resonance Studies ◽  
Local Distortions ◽  
Nuclear Magnetic

Nuclear Magnetic Resonance studies of Ga stabilized δ-Pu reveal detailed information about the local distortions surrounding the Ga impurities as well as provides information about the local spin fluctuations experienced by the Ga nuclei. The Ga NMR spectrum is inhomogeneously broadened by a distribution of local electric field gradients (EFGs), which indicates that the Ga experiences local distortions from cubic symmetry. The Knight shift and spin lattice relaxation rate indicate that the Ga is dominantly coupled to the Fermi surface via core polarization, and is inconsistent with magnetic order or low frequency spin correlations.

A 31P and 199Hg nuclear magnetic resonance and vibrational spectroscopic study of phosphine complexes of Hg(ClO4)2

1984 ◽  
Vol 62 (3) ◽  
pp. 621-627 ◽  
Author(s):  
Tim Allman ◽  
Ram G. Goel
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
Spectroscopic Study ◽  
Vibrational Spectroscopy ◽  
Low Frequency ◽  
Sample Concentration ◽  
Phosphine Complexes ◽  
Nuclear Magnetic

Cationic complexes of the type [Hg(phosphine)n](ClO4)2 (n = 2, 3, 4) (phosphine = P(t-Bu)3, PCy3, P(4-Me2NC6H4)3, P(4-MeOC6H4)3, P(4-MeC6H4)3, P(3-MeC6H4)3, P(2-MeC6H4)3, P(4-FC6H4)3, P(4-ClC6H4)3) have been prepared and studied by vibrational spectroscopy in the perchlorate and low frequency regions, as well as by 31P and 199Hg nmr. The skeletal Hg—P frequencies have been assigned in both solution and the solid state. It was found that 1J(Hg—P) decreases with increasing phosphine basicity and that it is also dependent upon sample concentration and temperature.

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