Helium-cooling and -spinning dynamic nuclear polarization for sensitivity-enhanced solid-state NMR at 14T and 30K

Matsuki, Yoh; Ueda, Kazuyuki; Idehara, T.; Ikeda, Ryosuke; Ogawa, I.; Nakamura, Shinji; Toda, Masaya; Anai, Takahiro; Fujiwara, Toshimichi

doi:10.1016/j.jmr.2012.09.008

Cited by 80 publications

(52 citation statements)

References 63 publications

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“…62 Second, several groups are developing helium cooled DNP systems. [63][64][65][66] Reducing the sample temperature to less than 30 K can potentially provide further absolute sensitivity gains of one to two orders of magnitude by increasing both DNP enhancements and thermal nuclear polarization. [63][64][65][66] Third, the development of coherent, pulsed microwave sources for time-domain high-field DNP could revolutionize the field in much the same way that pulsed methods revolutionized NMR spectroscopy.…”

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

“…[63][64][65][66] Reducing the sample temperature to less than 30 K can potentially provide further absolute sensitivity gains of one to two orders of magnitude by increasing both DNP enhancements and thermal nuclear polarization. [63][64][65][66] Third, the development of coherent, pulsed microwave sources for time-domain high-field DNP could revolutionize the field in much the same way that pulsed methods revolutionized NMR spectroscopy. Pulsed DNP will improve polarization transfer efficiency and make it possible to use simple monoradical PA. 67,68 It may also be possible to eliminate deleterious paramagnetic broadening effects with electron decoupling.…”

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

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Materials Characterization by Dynamic Nuclear Polarization-Enhanced Solid-State NMR Spectroscopy

Rossini

2018

J. Phys. Chem. Lett.

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High-resolution solid-state NMR spectroscopy is a powerful tool for the study of organic and inorganic materials because it can directly probe the symmetry and structure at nuclear sites, the connectivity/bonding of atoms and precisely measure inter-atomic distances. However, NMR spectroscopy is hampered by intrinsically poor sensitivity, consequently, the application of NMR spectroscopy to many solid materials is often infeasible. High-field dynamic nuclear polarization (DNP) has emerged as a technique to routinely enhance the sensitivity of solid-state NMR experiments by one to three orders of magnitude. This perspective gives a general overview of how DNP enables advanced solid-state NMR experiments on a variety of materials. DNP-enhanced solid-state NMR experiments provide unique insights into the molecular structure, which makes it possible to form structure-activity relationships that ultimately assist in the rational design and improvement of materials. Disciplines Materials Chemistry | Physical Chemistry CommentsThis document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review. To access the final edited and published work see doi: 10.1021/acs.jpclett.8b01891. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Abstract High-resolution solid-state NMR spectroscopy is a powerful tool for the study of organic and

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Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

Materials Characterization by Dynamic Nuclear Polarization-Enhanced Solid-State NMR Spectroscopy

Rossini

2018

J. Phys. Chem. Lett.

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“…However, the benefits are numerous, embracing an increased Boltzmann distribution (cf., ~0.1% 1H polarization at 10 K, ~0.003% at 300 K, all at 10 T), reduced Johnson-Nysquist noise in the radio frequency (RF) circuit, in addition of being able to study low-temperature phenomena at an atomic scale [22,26]. Hardware for ULT-MAS combined with DNP at temperatures <<100 K, has been developed in the teams of R. Griffin at the Massachusetts Institute of Technology (MIT), USA [12], R. Tycko in Bethesda (NIH), USA [14], and T. Fujiwara in Osaka, Japan [16]. The MIT design from 1997 employed He as both the spinning and cooling gases and gave substantial DNP enhancement, εon/off (the ratio of the intensities of the NMR signal detected in the presence and absence of microwave irradiation suitable for DNP) It was stated that the DNP enhancement dramatically improved by lowering the temperature from 100 (1Hεon/off ~5) to 55 (1Hεon/off ~20) to 25 K (1Hεon/off ~100) [12].…”

Section: Contemporary Approaches To "Ultra"-low Temperature Masmentioning

confidence: 99%

“…Extending this technique to the larger magnetic fields required for high-resolution solid state ssNMR studies occurred with the introduction of higher frequency and high-power continuous-wave microwave (μw) sources [8] and their combination with hardware providing low temperature samples under MAS [12], both facilitating saturation of the electron spin resonance and accordingly improving MAS-DNP efficiencies. Presently, commercial equipment supplying a full experimental setup of MAS-DNP is available at magnetic field strengths of 9, 14, and 19 T, with sample temperatures down to ~100 K. We [13,31], as well as others [12,[14][15][16], are working to demonstrate the further improvement in sensitivity and resolution by performing MAS-DNP at even lower temperatures. It implies the use of helium gas to cool down the spinning sample and technical solutions are far from trivial.…”

Section: Introductionmentioning

confidence: 99%

Ultra-Low Temperature Nuclear Magnetic Resonance

Bouleau

Lee

Saint-Bonnet

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Because NMR spectroscopy requests more sensitivity and more resolution, high-frequency and high-power microwave irradiation of electron spins in a magnetic field, Dynamic Nuclear Polarization (DNP) is becoming a common partner for fast sample spinning NMR experiments. Currently, this technics is performed at minimum sample temperatures ~100 K, using cold nitrogen gas to pneumatically spin and cool the sample. The desire is to improve NMR by providing ultra-low temperatures, using cryogenic helium gas. It is shown that stable and fast spinning can be attained for sample temperatures down to 30 K using a cryostat developed in our laboratory. Using this cryostat to cool a closed-loop of helium gas results in spinning frequencies that can greatly surpass those achievable with nitrogen gas. It results in substantial sensitivity enhancements (~ 600) and according experimental time-savings by 2 to 4 orders of magnitude. Therefore, access to this temperature range is demonstrated to be both viable and highly pertinent.

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“…The consumption of helium was around 1.6 l/h. The consumption of liquid helium in MAS-DNP is reported to be 6 l/h when used for cooling and spinning [114] and 1.3 l/h when used only for cooling [115]. In dissolution DNP every dissolution step consumes up to 2 liters of liquid helium.…”

Section: Rapid-melt Dnp Below 77kmentioning

confidence: 99%