Magic angle spinning spheres

Chen, Pin-Hui; Albert, Brice J.; Gao, Chukun; Alaniva, Nicholas; Price, Lauren E.; Scott, Faith J.; Saliba, Edward P.; Sesti, Erika L.; Judge, Patrick T.; Fisher, Edward; Barnes, Alexander B.

doi:10.1126/sciadv.aau1540

Cited by 46 publications

(37 citation statements)

References 45 publications

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“…Note that the maximum tested pressure was not limited by the rotors, as their spinning rates would be predicted to increase with increasing pressure, but rather the maximum pressure was limited to ∼4 Bar due to safety concerns with regard to the connecting assemblies. Rotor B's maximum observed rate was a significant improvement over our previous maximum of 4.6 kHz for 9.5 mm rotors in air, which was achieved using rotor A at 4.1 Bar (Chen et al (2018)). As rotor A also performed better in our current tests, with a maximum rate of 5.2 kHz at 4.1 Bar, we attribute some of the performance gains to the higher precision 3D printing of our latest stators.…”

Section: Discussion Open Accessmentioning

confidence: 50%

“…Spherical rotors spin within the hemispherical stator cup by the application of a gas stream along the rotor's equator from a converging nozzle tangent to the rotor surface (Chen et al (2018)). The nozzle aperture is placed at the complement of the magic angle (35.26°) in order to tilt the spinning axis of the rotor to a value near the magic angle.…”

Section: Resultsmentioning

confidence: 99%

“…79 Br spectra were taken at a transmitter frequency of 75.46 MHz and a MAS rate of 3.5 kHz. The implementation of a double saddle coil within the probe enabled the application of a 35 kHz B 1 field on 79 Br with 300 W incident RF power, a significant improvement over our previous implementation of 9.5 mm spherical rotors, which achieved a B 1 field of only 12.5 kHz using a split coil and 800 W incident RF power Chen et al (2018).…”

Section: Experimental Apparatusmentioning

confidence: 97%

“…MAS has traditionally been performed by spinning a cylindrical rotor within a stator installed at the magic angle, thereby requiring a gas bearing to stabilize the rotor and drive gas to apply torque (Andrew (1981); Doty and Ellis (1981); Wilhelm et al (2015)). However, we recently showed that it is possible to spin samples via a different paradigm, namely using spherical rotors spun using a single gas stream for both the bearing and drive (Chen et al (2018); Gao et al (2019)). This approach allows highly stable rotor spinning about a single axis inclined at the magic angle, with record rates as high as 4.6 kHz (N 2 , 4.1 Bar) and 10.6 kHz (He, 11 Bar) for 9.5 mm diameter rotors and 11.4 kHz (N 2 , 3.1 Bar) and 28 kHz (He, 7.6 Bar) for 4 mm diameter rotors.…”

Section: Introductionmentioning

confidence: 99%

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Highly Stable Magic Angle Spinning Spherical Rotors Lacking Turbine Grooves

Popp¹,

Däpp²,

Gao³

et al. 2020

Preprint

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Abstract. The use of spherical rotors for magic angle spinning offers a number of advantages including improved sample exchange, efficient microwave coupling for dynamic nuclear polarization nuclear magnetic resonance (NMR) experiments and, most significantly, high frequency and stable spinning with minimal risk of rotor crash. Here we demonstrate the sim- ple retrofitting of a commercial NMR probe with MAS spheres for solid-state NMR. We analyze a series of turbine groove geometries to investigate the importance of the rotor surface on spinning performance. Of note, rotors lacking any surface modification spin rapidly and stably even without feedback control. The high stability of a spherical rotor about the magic angle is shown to be dependent on its inertia tensor rather than the presence of turbine grooves.

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Section: Discussion Open Accessmentioning

confidence: 50%

Section: Resultsmentioning

confidence: 99%

Section: Experimental Apparatusmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Highly Stable Magic Angle Spinning Spherical Rotors Lacking Turbine Grooves

Popp¹,

Däpp²,

Gao³

et al. 2020

Preprint

Self Cite

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“…Lowering the temperature from 15 K to 7 K will further increase the electron polarization from 29 % to 65 % on a 7‐Tesla ( 1 H 300 MHz) spectrometer and from 55 % to 91 % on a 14 Tesla ( 1 H 600 MHz) corresponding to at least a two‐fold potential improvement in DNP performance. The sample spinning rate at these extreme temperatures is lower than at higher temperatures and is likely to remain a limitation for some applications, but rotors of smaller diameter and alternative configurations such as recently reported spinning spheres should enable further improvements …”

Section: Hardware For Mas‐dnp Experiments At Temperatures Below 100 Kmentioning

confidence: 99%

Recent Advances in Magic Angle Spinning‐Dynamic Nuclear Polarization Methodology

Kaminker

2019

Israel Journal of Chemistry

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Dynamic nuclear polarization (DNP) is a method to boost the nuclear magnetic resonance (NMR) signal and thus alleviate the main limitation of NMR spectroscopy-its low sensitivity. One particularly successful methodology is the combination of DNP with magic angle spinning (MAS). MAS-DNP enables orders of magnitude signal enhancements in solid-state NMR experiments. The success of modern MAS-DNP stems from a combination of multiple developments in hardware, polarization agents design, sample preparation, theoretical understanding, and experimental methodology. Altogether these developments have allowed numerous breakthrough applications in biology and materials science. Despite its proven successes, ongoing research aims to further optimize hardware and polarization agent chemistry. Recent advances in MAS-DNP methodology that will allow unprecedented sensitivity in novel future applications are reviewed in this manuscript. Figure 3. (a) Schematic (left) and photograph (right) of the spinning module of nitrogen drive and bearing gas/helium-cooled design. (b-c) Schematics of the closed-loop helium-based DNP systems as developed (b) at the University of Grenoble Alpes and (c) at the Osaka University. Adapted from references 53, 48, 49 respectively.

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Opportunities and Challenges in Applying Solid‐State NMR Spectroscopy in Organic Mechanochemistry

et al. 2023

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In recent years it was shown that mechanochemical strategies can be beneficial in directed conversions of organic compounds. Finding new reactions proved difficult, and due to the lack of mechanistic understanding of mechanochemical reaction events, respective efforts have mostly remained empirical. Spectroscopic techniques are crucial in shedding light on these questions. In this overview, the opportunities and challenges of solid‐state nuclear magnetic resonance (NMR) spectroscopy in the field of organic mechanochemistry are discussed. After a brief discussion of the basics of high‐resolution solid‐state NMR under magic‐angle spinning (MAS) conditions, seven opportunities for solid‐state NMR in the field of organic mechanochemistry are presented, ranging from ex‐situ approaches to structurally elucidate reaction products obtained by milling to the potential and limitations of in‐situ solid‐state NMR approaches. Particular strengths of solid‐state NMR, for instance in differentiating polymorphs, in NMR‐crystallographic structure‐determination protocols, or in detecting weak noncovalent interactions in molecular‐recognition events employing proton‐detected solid‐state NMR experiments at fast MAS frequencies, are discussed.This article is protected by copyright. All rights reserved

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Magic angle spinning spheres

Abstract: Spherical rotors can be used for magic angle spinning nuclear magnetic resonance.

Cited by 46 publications

References 45 publications

Highly Stable Magic Angle Spinning Spherical Rotors Lacking Turbine Grooves

Highly Stable Magic Angle Spinning Spherical Rotors Lacking Turbine Grooves

Recent Advances in Magic Angle Spinning‐Dynamic Nuclear Polarization Methodology

Opportunities and Challenges in Applying Solid‐State NMR Spectroscopy in Organic Mechanochemistry

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