H2-decoupling-accelerated H1 spin diffusion in dynamic nuclear polarization with photoexcited triplet electrons

By combining two methods of selective doping of paramagnetic species into a microdomain and small-angle neutron scattering (SANS), thespatially inhomogeneous proton polarizationcreated by dynamic nuclear polarization (DNP) has been precisely evaluated. A lamella-forming diblock copolymer composed of polystyrene (PS) and polyisoprene (PI) block chains (PS-b-PI) was employed, the SANS profile of which clearly shows scattering peaks up to the third order due to interlamellar interference. As a source of electron spin for DNP, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) was doped into one or other of the microdomains; samples with PS or PI microdomains selectively doped with TEMPO are designated PS.-b-PI and PS-b-PI., respectively. The SANS intensity at the first- and third-order peaks is well reproduced by assuming that the proton polarization is homogeneous throughout the sample, but that at the second-order peak cannot be explained by this assumption. This anomaly regarding the second-order peak was successfully explained by a model postulating that proton polarization in a doped microdomain decreases with increasing distance from the interface with a neighbouring doped microdomain. The decrease in proton polarization at the centre of a doped microdomain was estimated to be 0.07 (2) for PS-b-PI.and 0.05 (1) for PS.-b-PI, relative to constant proton polarization in a doped microdomain. The inhomogeneous proton polarization results from two competing dynamic processes,i.e.spin diffusion from doped to undoped microdomains, and spin lattice relaxation occurring on the pathway of proton spin diffusion.

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Electron-driven spin diffusion supports crossing the diffusion barrier in MAS DNP

Physical Chemistry Chemical Physics ◽

10.1039/c8cp00265g ◽

2018 ◽

Vol 20 (16) ◽

pp. 11418-11429 ◽

Cited By ~ 8

Author(s):

Johannes J. Wittmann ◽

Michael Eckardt ◽

Wolfgang Harneit ◽

Björn Corzilius

Keyword(s):

Dynamic Nuclear Polarization ◽

Diffusion Barrier ◽

Nuclear Polarization ◽

Spin Diffusion ◽

Hyperfine Interactions ◽

Magic Angle Spinning ◽

Magic Angle ◽

Diffusion Rates ◽

Angle Spinning

Hyperfine interactions can quench homonuclear spin-diffusion in the direct vicinity of a polarizing agent in dynamic nuclear polarization (DNP). However, under magic-angle spinning (MAS), the same interactions may also enhance the spin-diffusion rates through an electron-driven spin diffusion (EDSD) mechanism introduced here.

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Tracing Dynamic Nuclear Polarization Pathways Using Transition Metal - Nuclear Spin Rulers

10.26434/chemrxiv.11340752 ◽

2019 ◽

Author(s):

Sheetal Kumar Jain ◽

Chung-Jui Yu ◽

Blake Wilson ◽

Tarnuma Tabassum ◽

Danna E. Freedman ◽

...

Keyword(s):

Transition Metal ◽

Dynamic Nuclear Polarization ◽

Nuclear Spin ◽

Pulse Shaping ◽

Nuclear Polarization ◽

Spin Diffusion ◽

Protein Structures ◽

Organic Radical ◽

Waveform Generator ◽

Low Sensitivity

<a></a>The ubiquitous technique of nuclear magnetic resonance (NMR) spectroscopy suffers from relatively low sensitivity due to the low polarization of nuclei. For decades, the technique of dynamic nuclear polarization (DNP) has been harnessed to increase the sensitivity of NMR, enabling detection of low abundance nuclei such as 17O and elucidation of protein structures. Yet, the catalogue of DNP agents today is limited to organic radical species, accompanied by a handful of metal ions (Cr3+, Mn2+, and Gd3+). This study significantly expands the scope and catalogue of DNP with the first demonstration of amplification of nuclear spin polarization at a set distance from a transition metal center (V4+) that has g-values significantly varied from 2 and anisotropic EPR line that is more than 3GHz broad.We showed that 1H NMR signal enhancements of up to 33 can be achieved at 6.9T field and 4K temperature using a home-built DNP instrumentation that allows microwave irradiation over a frequency range of more than 10 GHz with pulse shaping capabilities by arbitrary waveform generator. A series of systematically designed vanadyl complexes, with V4+-1H distances in range 4.0 Å to 13.6 Å, was used to trace the polarization pathway of DNP and determine the size of the spin-diffusion barrier.

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Dynamic Nuclear Polarization and Spin Diffusion in Nonconducting Solids

Applied Magnetic Resonance ◽

10.1007/s00723-008-0123-7 ◽

2008 ◽

Vol 34 (3-4) ◽

pp. 409-421 ◽

Cited By ~ 53

Author(s):

C. Ramanathan

Keyword(s):

Dynamic Nuclear Polarization ◽

Nuclear Polarization ◽

Spin Diffusion

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Multistability and spin diffusion enhanced lifetimes in dynamic nuclear polarization in a double quantum dot

Physical Review B ◽

10.1103/physrevb.92.245303 ◽

2015 ◽

Vol 92 (24) ◽

Cited By ~ 2

Author(s):

F. Forster ◽

M. Mühlbacher ◽

D. Schuh ◽

W. Wegscheider ◽

G. Giedke ◽

...

Keyword(s):

Quantum Dot ◽

Dynamic Nuclear Polarization ◽

Nuclear Polarization ◽

Spin Diffusion ◽

Double Quantum ◽

Double Quantum Dot

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Porous functionalized polymers enable generating and transporting hyperpolarized mixtures of metabolites

Nature Communications ◽

10.1038/s41467-021-24279-2 ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Théo El Daraï ◽

Samuel F. Cousin ◽

Quentin Stern ◽

Morgan Ceillier ◽

James Kempf ◽

...

Keyword(s):

Solid State ◽

Dynamic Nuclear Polarization ◽

Nuclear Polarization ◽

Spin Diffusion ◽

Relaxation Times ◽

Functionalized Polymers ◽

Cross Polarization ◽

Biological Interest ◽

Remote Preparation ◽

Bulk Matrix

AbstractHyperpolarization by dissolution dynamic nuclear polarization (dDNP) has enabled promising applications in spectroscopy and imaging, but remains poorly widespread due to experimental complexity. Broad democratization of dDNP could be realized by remote preparation and distribution of hyperpolarized samples from dedicated facilities. Here we show the synthesis of hyperpolarizing polymers (HYPOPs) that can generate radical- and contaminant-free hyperpolarized samples within minutes with lifetimes exceeding hours in the solid state. HYPOPs feature tunable macroporous porosity, with porous volumes up to 80% and concentration of nitroxide radicals grafted in the bulk matrix up to 285 μmol g−1. Analytes can be efficiently impregnated as aqueous/alcoholic solutions and hyperpolarized up to P(13C) = 25% within 8 min, through the combination of 1H spin diffusion and 1H → 13C cross polarization. Solutions of 13C-analytes of biological interest hyperpolarized in HYPOPs display a very long solid-state 13C relaxation times of 5.7 h at 3.8 K, thus prefiguring transportation over long distances.

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Propagation of dynamic nuclear polarization across the xenon cluster boundaries: Elucidation of the spin-diffusion bottleneck

Journal of Magnetic Resonance ◽

10.1016/j.jmr.2013.07.006 ◽

2013 ◽

Vol 235 ◽

pp. 71-76 ◽

Cited By ~ 10

Author(s):

M. Pourfathi ◽

N.N. Kuzma ◽

H. Kara ◽

R.K. Ghosh ◽

H. Shaghaghi ◽

...

Keyword(s):

Dynamic Nuclear Polarization ◽

Nuclear Polarization ◽

Spin Diffusion ◽

Xenon Cluster

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Spin Temperature and Dynamic Nuclear Polarization. From the History of Researches (1953 – 1983)

Substantia ◽

10.36253/substantia-1224 ◽

2021 ◽

Vol 5 (2) ◽

pp. 19-34

Author(s):

Aleksander Kessenikh

Keyword(s):

Dynamic Nuclear Polarization ◽

Nuclear Polarization ◽

Spin Diffusion ◽

Nuclear Spins ◽

Spin Temperature ◽

The Public ◽

History Of Research ◽

Nuclear Magnetic Spectroscopy ◽

History Of

An attempt is proposed in the most concise form to provide the reader with a history of research and applications of dynamic nuclear polarization (DNP). The main attention is paid to the first three decades of DNP research, and the history of the discovery and development of multiparticle DNP and its relationship with the spin temperature approximation are outlined in some detail. The article emphasizes the role of such researchers as Anatol Abraham, Maurice Goldman, Michel Borghini, Thomas Wenckebach, Vadim Atsarkin, Boris Provotorov, Maya Rodak, Mortko Kozhushner, Levan Buishvili, Givi Khutsishvili. As far as possible, the contributions of many other scientists are considered. The establishment of a uniform temperature for nuclear spins due to the effect of spin diffusion was first proposed by Nicholas Blombergen in 1949. The content of the article is based on the bibliography available in the public domains, in particular on the memoirs of the research participants, and first of all on the materials of Atsarkin's 1978 review in Sov. Phys. Uspekhi and on the oral history of the development of the multiparticle concept of DNP effects, recorded from the speeches of the participants of the Moscow seminar "Problems of Magnetic Resonance" in 2001. A simplified description of the effects of DNP and a summary of the history of their discovery is given in section “Introduction”. The shortest biographical data and portraits of participants in the DNP study are given in Appendix 1, and a selected bibliography on the problems of DNP and spin temperatures is given in Appendix 2. The bibliography divided into four sections according to the time and type of publication (I - historical research, memoirs; II – monographs, reviews; III - original publications 1953 - 1983; IV – some original publications of a later time, mainly during the transformation of DNP into an method for the implementation of nuclear magnetic spectroscopy and tomography in the interests of chemistry, biochemistry and medicine). The widespread use of DNP methods is evidenced, for example, by the fact, that by now company Bruker BioSpin has installed about 50 gyrotron based spectrometers for DNP operating upto 593 GHz worldwide to date.

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Tracing Dynamic Nuclear Polarization Pathways Using Transition Metal - Nuclear Spin Rulers

10.26434/chemrxiv.11340752.v1 ◽

2019 ◽

Author(s):

Sheetal Kumar Jain ◽

Chung-Jui Yu ◽

Blake Wilson ◽

Tarnuma Tabassum ◽

Danna E. Freedman ◽

...

Keyword(s):

Transition Metal ◽

Dynamic Nuclear Polarization ◽

Nuclear Spin ◽

Pulse Shaping ◽

Nuclear Polarization ◽

Spin Diffusion ◽

Protein Structures ◽

Organic Radical ◽

Waveform Generator ◽

Low Sensitivity

<a></a>The ubiquitous technique of nuclear magnetic resonance (NMR) spectroscopy suffers from relatively low sensitivity due to the low polarization of nuclei. For decades, the technique of dynamic nuclear polarization (DNP) has been harnessed to increase the sensitivity of NMR, enabling detection of low abundance nuclei such as 17O and elucidation of protein structures. Yet, the catalogue of DNP agents today is limited to organic radical species, accompanied by a handful of metal ions (Cr3+, Mn2+, and Gd3+). This study significantly expands the scope and catalogue of DNP with the first demonstration of amplification of nuclear spin polarization at a set distance from a transition metal center (V4+) that has g-values significantly varied from 2 and anisotropic EPR line that is more than 3GHz broad.We showed that 1H NMR signal enhancements of up to 33 can be achieved at 6.9T field and 4K temperature using a home-built DNP instrumentation that allows microwave irradiation over a frequency range of more than 10 GHz with pulse shaping capabilities by arbitrary waveform generator. A series of systematically designed vanadyl complexes, with V4+-1H distances in range 4.0 Å to 13.6 Å, was used to trace the polarization pathway of DNP and determine the size of the spin-diffusion barrier.

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