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Levien M, Yang L, van der Ham A, Reinhard M, John M, Purea A, Ganz J, Marquardsen T, Tkach I, Orlando T, Bennati M. Overhauser enhanced liquid state nuclear magnetic resonance spectroscopy in one and two dimensions. Nat Commun 2024; 15:5904. [PMID: 39003303 PMCID: PMC11246421 DOI: 10.1038/s41467-024-50265-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 07/02/2024] [Indexed: 07/15/2024] Open
Abstract
Nuclear magnetic resonance (NMR) is fundamental in the natural sciences, from chemical analysis and structural biology, to medicine and physics. Despite its enormous achievements, one of its most severe limitations is the low sensitivity, which arises from the small population difference of nuclear spin states. Methods such as dissolution dynamic nuclear polarization and parahydrogen induced hyperpolarization can enhance the NMR signal by several orders of magnitude, however, their intrinsic limitations render multidimensional hyperpolarized liquid-state NMR a challenge. Here, we report an instrumental design for 9.4 Tesla liquid-state dynamic nuclear polarization that enabled enhanced high-resolution NMR spectra in one and two-dimensions for small molecules, including drugs and metabolites. Achieved enhancements of up to two orders of magnitude translate to signal acquisition gains up to a factor of 10,000. We show that hyperpolarization can be transferred between nuclei, allowing DNP-enhanced two-dimensional 13C-13C correlation experiments at 13C natural abundance. The enhanced sensitivity opens up perspectives for structural determination of natural products or characterization of drugs, available in small quantities. The results provide a starting point for a broader implementation of DNP in liquid-state NMR.
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Affiliation(s)
- Marcel Levien
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Institute of Physical Chemistry, Department of Chemistry, Georg-August-University, Tammannstr. 6, 37077, Göttingen, Germany
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Luming Yang
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Alex van der Ham
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Maik Reinhard
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Institute of Physical Chemistry, Department of Chemistry, Georg-August-University, Tammannstr. 6, 37077, Göttingen, Germany
| | - Michael John
- Institute of Organic and Biomolecular Chemistry, Department of Chemistry, Georg-August-University, Tammannstr. 2, 37077, Göttingen, Germany
| | - Armin Purea
- Bruker Biospin GmbH, Rudolf-Plank-Str. 23, 76275, Ettlingen, Germany
| | - Jürgen Ganz
- Bruker Biospin GmbH, Rudolf-Plank-Str. 23, 76275, Ettlingen, Germany
| | | | - Igor Tkach
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Tomas Orlando
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., 32310, Tallahassee, FL, USA
| | - Marina Bennati
- Electron-Spin Resonance Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany.
- Institute of Physical Chemistry, Department of Chemistry, Georg-August-University, Tammannstr. 6, 37077, Göttingen, Germany.
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2
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Tobar C, Albanese K, Chaklashiya R, Equbal A, Hawker C, Han S. Multi Electron Spin Cluster Enabled Dynamic Nuclear Polarization with Sulfonated BDPA. J Phys Chem Lett 2023; 14:11640-11650. [PMID: 38108283 DOI: 10.1021/acs.jpclett.3c02428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Dynamic nuclear polarization (DNP) can amplify the solid-state nuclear magnetic resonance (NMR) signal by several orders of magnitude. The mechanism of DNP utilizing α,γ-bisdiphenylene-β-phenylallyl (BDPA) variants as Polarizing Agents (PA) has been the subject of lively discussions on account of their remarkable DNP efficiency with low demand for microwave power. We propose that electron spin clustering of sulfonated BDPA is responsible for its DNP performance, as revealed by the temperature-dependent shape of the central DNP profile and strong electron-electron (e-e) crosstalk seen by Electron Double Resonance. We demonstrate that a multielectron spin cluster can be modeled with three coupled spins, where electron J (exchange) coupling between one of the e-e pairs matching the NMR Larmor frequency induces the experimentally observed absorptive central DNP profile, and the electron T1e modulated by temperature and magic-angle spinning alters the shape between an absorptive and dispersive feature. Understanding the microscopic origin is key to designing new PAs to harness the microwave-power-efficient DNP effect observed with BDPA variants.
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Affiliation(s)
- Celeste Tobar
- Department of Chemistry and Biochemistry, University of California, Santa Barbara 93106, California, United States
| | - Kaitlin Albanese
- Materials Department, University of California, Santa Barbara 93106, California, United States
| | - Raj Chaklashiya
- Materials Department, University of California, Santa Barbara 93106, California, United States
| | - Asif Equbal
- Department of Chemistry, NYU Abu Dhabi, Saadiyat Campus, PO Box 129188, Abu Dhabi 00000, United Arab Emirates
| | - Craig Hawker
- Materials Department, University of California, Santa Barbara 93106, California, United States
| | - Songi Han
- Department of Chemistry, Northwestern University, Evanston 60208, Illinois, United States
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3
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Sezer D, Dai D, Prisner T. The solid effect of dynamic nuclear polarization in liquids - accounting for g-tensor anisotropy at high magnetic fields. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2023; 4:243-269. [PMID: 38111486 PMCID: PMC10726030 DOI: 10.5194/mr-4-243-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 09/15/2023] [Indexed: 12/20/2023]
Abstract
In spite of its name, the solid effect of dynamic nuclear polarization (DNP) is also operative in viscous liquids, where the dipolar interaction between the polarized nuclear spins and the polarizing electrons is not completely averaged out by molecular diffusion on the timescale of the electronic spin-spin relaxation time. Under such slow-motional conditions, it is likely that the tumbling of the polarizing agent is similarly too slow to efficiently average the anisotropies of its magnetic tensors on the timescale of the electronic T 2 . Here we extend our previous analysis of the solid effect in liquids to account for the effect of g -tensor anisotropy at high magnetic fields. Building directly on the mathematical treatment of slow tumbling in electron spin resonance , we calculate solid-effect DNP enhancements in the presence of both translational diffusion of the liquid molecules and rotational diffusion of the polarizing agent. To illustrate the formalism, we analyze high-field (9.4 T) DNP enhancement profiles from nitroxide-labeled lipids in fluid lipid bilayers. By properly accounting for power broadening and motional broadening, we successfully decompose the measured DNP enhancements into their separate contributions from the solid and Overhauser effects.
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Affiliation(s)
- Deniz Sezer
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
| | - Danhua Dai
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
| | - Thomas F. Prisner
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
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4
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Zhao Y, El Mkami H, Hunter RI, Casano G, Ouari O, Smith GM. Large cross-effect dynamic nuclear polarisation enhancements with kilowatt inverting chirped pulses at 94 GHz. Commun Chem 2023; 6:171. [PMID: 37607991 PMCID: PMC10444895 DOI: 10.1038/s42004-023-00963-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/25/2023] [Indexed: 08/24/2023] Open
Abstract
Dynamic nuclear polarisation (DNP) is a process that transfers electron spin polarisation to nuclei by applying resonant microwave radiation, and has been widely used to improve the sensitivity of nuclear magnetic resonance (NMR). Here we demonstrate new levels of performance for static cross-effect proton DNP using high peak power chirped inversion pulses at 94 GHz to create a strong polarisation gradient across the inhomogeneously broadened line of the mono-radical 4-amino TEMPO. Enhancements of up to 340 are achieved at an average power of a few hundred mW, with fast build-up times (3 s). Experiments are performed using a home-built wideband kW pulsed electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz, integrated with an NMR detection system. Simultaneous DNP and EPR characterisation of other mono-radicals and biradicals, as a function of temperature, leads to additional insights into limiting relaxation mechanisms and give further motivation for the development of wideband pulsed amplifiers for DNP at higher frequencies.
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Affiliation(s)
- Yujie Zhao
- School of Physics and Astronomy, University of St Andrews, KY16 9SS, Fife, Scotland
| | - Hassane El Mkami
- School of Physics and Astronomy, University of St Andrews, KY16 9SS, Fife, Scotland
| | - Robert I Hunter
- School of Physics and Astronomy, University of St Andrews, KY16 9SS, Fife, Scotland
| | - Gilles Casano
- Aix Marseille University, CNRS, ICR, UMR 7273, F-13013, Marseille, France
| | - Olivier Ouari
- Aix Marseille University, CNRS, ICR, UMR 7273, F-13013, Marseille, France
| | - Graham M Smith
- School of Physics and Astronomy, University of St Andrews, KY16 9SS, Fife, Scotland.
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5
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Dai D, Denysenkov V, Bagryanskaya EG, Tormyshev VM, Prisner TF, Kuzhelev AA. 13C Hyperpolarization of Viscous Liquids by Transfer of Solid-Effect 1H Dynamic Nuclear Polarization at High Magnetic Field. J Phys Chem Lett 2023; 14:7059-7064. [PMID: 37526333 DOI: 10.1021/acs.jpclett.3c01732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Dynamic nuclear polarization (DNP) is routinely used as a method for increasing the sensitivity to nuclear magnetic resonance (NMR). Recently, high-field solid-effect DNP in viscous liquids on 1H nuclei was demonstrated using narrow-line polarizing agents. Here we expand the applicability of DNP in viscous media to 13C nuclei. To hyperpolarize 13C nuclei, we combined solid-effect 1H DNP with a subsequent transfer of the 1H polarization to 13C via insensitive nuclei enhanced by polarization transfer (INEPT). We demonstrate this approach using a triarylmethyl radical as a polarizing agent and glycerol-13C3 as an analyte. We achieved 13C enhancement factors of up to 45 at a magnetic field of 9.4 T and room temperature.
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Affiliation(s)
- Danhua Dai
- Goethe University Frankfurt am Main, Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Max von Laue Str. 7, Frankfurt am Main 60438, Germany
| | - Vasyl Denysenkov
- Goethe University Frankfurt am Main, Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Max von Laue Str. 7, Frankfurt am Main 60438, Germany
| | - Elena G Bagryanskaya
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, Novosibirsk 630090, Russia
| | - Victor M Tormyshev
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, Novosibirsk 630090, Russia
| | - Thomas F Prisner
- Goethe University Frankfurt am Main, Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Max von Laue Str. 7, Frankfurt am Main 60438, Germany
| | - Andrei A Kuzhelev
- Goethe University Frankfurt am Main, Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Max von Laue Str. 7, Frankfurt am Main 60438, Germany
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6
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Sezer D. The solid effect of dynamic nuclear polarization in liquids. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2023; 4:153-174. [PMID: 37904804 PMCID: PMC10583289 DOI: 10.5194/mr-4-153-2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/23/2023] [Indexed: 11/01/2023]
Abstract
The solid-state effect of dynamic nuclear polarization (DNP) is operative also in viscous liquids where the dipolar interaction between the electronic and nuclear spins is partially averaged. The proper way to quantify the degree of averaging, and thus calculate the efficiency of the effect, should be based on the time-correlation function of the dipolar interaction. Here we use the stochastic Liouville equation formalism to develop a general theoretical description of the solid effect in liquids. The derived expressions can be used with different dipolar correlations functions depending on the assumed motional model. At high magnetic fields, the theory predicts DNP enhancements at small offsets, far from the classical solid-effect positions that are displaced by one nuclear Larmor frequency from the electronic resonance. The predictions are in quantitative agreement with such enhancement peaks observed at 9.4 T . These non-canonical peaks are not due to thermal mixing or the cross effect but exactly follow the dispersive component of the EPR line.
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Affiliation(s)
- Deniz Sezer
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
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7
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Sezer D. Non-perturbative treatment of the solid effect of dynamic nuclear polarization. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2023; 4:129-152. [PMID: 37904797 PMCID: PMC10583281 DOI: 10.5194/mr-4-129-2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/25/2023] [Indexed: 11/01/2023]
Abstract
In the solid effect of dynamic nuclear polarization (DNP), the concerted flips of the electronic and nuclear spins, which are needed for polarization transfer, are induced by the microwaves. Commonly, the effect of the microwaves is modeled by a rate process whose rate constant is determined perturbatively. According to quantum mechanics, however, the coherent microwave excitation leads to Rabi nutation, which corresponds to a rotation rather than a rate process. Here we reconcile the coherent effect of the microwaves with the description by rate equations by focusing only on the steady state of the spin dynamics. We show that the phenomenological rate constants describing the synchronous excitation of the electronic and nuclear spins can be selected such that the description by rate equations yields the same steady state as the exact quantum-mechanical treatment. The resulting non-perturbative rates differ from the classical, perturbative ones and remain valid also at the high microwave powers used in modern-day DNP. Our treatment of the solid effect highlights the role of the coherences in the mechanistic steps of polarization transfer and reveals the importance of the dispersive (i.e., out-of-phase) component of the EPR line. Interestingly, the multiplicative dependence of the DNP enhancement on the dispersive EPR component was intuited in the very first report of the solid effect in liquids . The time-domain description of the solid effect developed here is extendable to liquids, where the dipolar interaction changes randomly in time due to molecular diffusion.
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Affiliation(s)
- Deniz Sezer
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
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8
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Kuzhelev AA, Denysenkov V, Ahmad IM, Rogozhnikova OY, Trukhin DV, Bagryanskaya EG, Tormyshev VM, Sigurdsson ST, Prisner TF. Solid-Effect Dynamic Nuclear Polarization in Viscous Liquids at 9.4 T Using Narrow-Line Polarizing Agents. J Am Chem Soc 2023; 145:10268-10274. [PMID: 37104685 DOI: 10.1021/jacs.3c01358] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Dynamic nuclear polarization (DNP) is a hyperpolarization method that is widely used for increasing the sensitivity of nuclear magnetic resonance (NMR) experiments. DNP is efficient in solid-state and liquid-state NMR, but its implementation in the intermediate state, namely, viscous media, is still less explored. Here, we show that a 1H DNP enhancement of over 50 can be obtained in viscous liquids at a magnetic field of 9.4 T and a temperature of 315 K. This was accomplished by using narrow-line polarizing agents in glycerol, both the water-soluble α,γ-bisdiphenylen-β-phenylallyl (BDPA) and triarylmethyl radicals, and a microwave/RF double-resonance probehead. We observed DNP enhancements with a field profile indicative of the solid effect and investigated the influence of microwave power, temperature, and concentration on the 1H NMR results. To demonstrate potential applications of this new DNP approach for chemistry and biology, we show hyperpolarized 1H NMR spectra of tripeptides, triglycine, and glypromate, in glycerol-d8.
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Affiliation(s)
- Andrei A Kuzhelev
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Straße 7, 60438 Frankfurt am Main, Germany
| | - Vasyl Denysenkov
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Straße 7, 60438 Frankfurt am Main, Germany
| | - Iram M Ahmad
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| | - Olga Yu Rogozhnikova
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia
| | - Dmitry V Trukhin
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia
| | - Elena G Bagryanskaya
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia
| | - Victor M Tormyshev
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Acad. Lavrentiev Avenue 9, 630090 Novosibirsk, Russia
| | - Snorri Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Straße 7, 60438 Frankfurt am Main, Germany
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9
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Reinhard M, Levien M, Bennati M, Orlando T. Large 31P-NMR enhancements in liquid state dynamic nuclear polarization through radical/target molecule non-covalent interaction. Phys Chem Chem Phys 2022; 25:822-828. [PMID: 36511338 PMCID: PMC9768845 DOI: 10.1039/d2cp04092a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dynamic nuclear polarization (DNP) is a method to enhance the low sensitivity of nuclear magnetic resonance (NMR) via spin polarization transfer from electron spins to nuclear spins. In the liquid state, this process is mediated by fast modulations of the electron-nuclear hyperfine coupling and its efficiency depends strongly on the applied magnetic field. A peculiar case study is triphenylphosphine (PPh3) dissolved in benzene and doped with BDPA radical because it gives 31P-NMR signal enhancements of two orders of magnitude up to a magnetic field of 14.1 T. Here we show that the large 31P enhancements of BDPA/PPh3 in benzene at 1.2 T (i) decrease when the moieties are dissolved in other organic solvents, (ii) are strongly reduced when using a nitroxide radical, and (iii) vanish with pentavalent 31P triphenylphosphine oxide. Those experimental observations are rationalized with numerical calculations based on density functional theory that show the tendency of BDPA and PPh3 to form a weak complex via non-covalent interaction that leads to large hyperfine couplings to 31P (ΔAiso ≥ 13 MHz). This mechanism is hampered in other investigated systems. The case study of 31P-DNP in PPh3 is an important example that extends the current understanding of DNP in the liquids state: non-covalent interactions between radical and target can be particularly effective to obtain large NMR signal enhancements.
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Affiliation(s)
- Maik Reinhard
- ESR Spectroscopy Group, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11GöttingenGermany,Department of Chemistry, Georg-August-University, Tammannstraße 4GöttingenGermany
| | - Marcel Levien
- ESR Spectroscopy Group, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11GöttingenGermany,Department of Chemistry, Georg-August-University, Tammannstraße 4GöttingenGermany
| | - Marina Bennati
- ESR Spectroscopy Group, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11GöttingenGermany,Department of Chemistry, Georg-August-University, Tammannstraße 4GöttingenGermany
| | - Tomas Orlando
- ESR Spectroscopy Group, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11GöttingenGermany
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Gizatullin B, Mattea C, Stapf S. Three mechanisms of room temperature dynamic nuclear polarization occur simultaneously in an ionic liquid. Phys Chem Chem Phys 2022; 24:27004-27008. [DOI: 10.1039/d2cp03437a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
For the first time, several mechanisms of dynamic nuclear polarization, namely Overhauser, solid effect and cross effect/thermal mixing, have been identified in an ionic liquid with a nitroxide radical at ambient temperatures.
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Affiliation(s)
- Bulat Gizatullin
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany
| | - Carlos Mattea
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany
| | - Siegfried Stapf
- FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany
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