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Tognetti J, Franks WT, Lewandowski JR, Brown SP. Optimisation of 1H PMLG homonuclear decoupling at 60 kHz MAS to enable 15N-1H through-bond heteronuclear correlation solid-state NMR spectroscopy. Phys Chem Chem Phys 2022; 24:20258-20273. [PMID: 35975627 PMCID: PMC9429863 DOI: 10.1039/d2cp01041k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Lee–Goldburg condition for homonuclear decoupling in 1H magic-angle spinning (MAS) solid-state NMR sets the angle θ, corresponding to arctan of the ratio of the rf nutation frequency, ν1, to the rf offset, to be the magic angle, θm, equal to tan−1(√2) = 54.7°. At 60 kHz MAS, we report enhanced decoupling compared to MAS alone in a 1H spectrum of 15N-glycine with at θ = 30° for a ν1 of ∼100 kHz at a 1H Larmor frequency, ν0, of 500 MHz and 1 GHz, corresponding to a high chemical shift scaling factor (λCS) of 0.82. At 1 GHz, we also demonstrate enhanced decoupling compared to 60 kHz MAS alone for a lower ν1 of 51 kHz, i.e., a case where the nutation frequency is less than the MAS frequency, with θ = 18°, λCS = 0.92. The ratio of the rotor period to the decoupling cycle time, Ψ = τr/τc, is in the range 0.53 to 0.61. Windowed decoupling using the optimised parameters for a ν1 of ∼100 kHz also gives good performance in a 1H spin-echo experiment, enabling implementation in a 1H-detected 15N–1H cross polarisation (CP)-refocused INEPT heteronuclear correlation NMR experiment. Specifically, initial 15N transverse magnetisation as generated by 1H–15N CP is transferred back to 1H using a refocused INEPT pulse sequence employing windowed 1H decoupling. Such an approach ensures the observation of through-bond N–H connectivities. For 15N-glycine, while the CP-refocused INEPT experiment has a lower sensitivity (∼50%) as compared to a double CP experiment (with a 200 μs 15N to 1H CP contact time), there is selectivity for the directly bonded NH3+ moiety, while intensity is observed for the CH21H resonances in the double CP experiment. Two-dimensional 15N–1H correlation MAS NMR spectra are presented for the dipeptide β-AspAla and the pharmaceutical cimetidine at 60 kHz MAS, both at natural isotopic abundance. For the dipeptide β-AspAla, different build-up dependence on the first spin-echo duration is observed for the NH and NH3+ moieties demonstrating that the experiment could be used to distinguish resonances for different NHx groups. 15N–1H heteronuclear NMR correlation at natural abundance in the solid state via J couplings is enabled by optimisation of phase-modulated Lee–Goldburg (PMLG) 1H homonuclear decoupling during the spin echoes, far from the ideal magic-angle condition.![]()
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Affiliation(s)
- Jacqueline Tognetti
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
| | - W Trent Franks
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
| | | | - Steven P Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
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2
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Paruzzo FM, Emsley L. High-resolution 1H NMR of powdered solids by homonuclear dipolar decoupling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 309:106598. [PMID: 31586820 DOI: 10.1016/j.jmr.2019.106598] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/13/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
The development of homonuclear dipolar decoupling sequences to obtain high-resolution 1H NMR spectra from solids has recently celebrated its 50th birthday. Over the years, a series of different decoupling schemes have been developed, starting with the pioneering Lee-Goldburg and WAHUHA sequences up to the most recent generation of experimentally optimized phase-modulated schemes such as eDUMBO-122 and LG4. These schemes can all yield over an order of magnitude reduction in 1H NMR linewidths in solids. Here we provide an overview and a broad experimental comparison of the performance of the main sequences, which has so far been absent in the literature, especially between the newest and the oldest decoupling schemes. We compare experimental results obtained using eight different decoupling schemes (LG, WHH-4, MREV-8, BR-24, FSLG/PMLG, DUMBO-1, eDUMBO-122 and LG4) on three different microcrystalline powdered samples (alanine, glycine and β-AspAla) and at three different MAS rates (3.0, 12.5 and 22.0 kHz). Finally, since these sequences can be technically demanding, we describe the experimental protocol we have used to optimize these schemes with the aim to provide simple guidelines for the optimization of CRAMPS experiments for all NMR users.
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Affiliation(s)
- Federico M Paruzzo
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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3
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Sternberg U, Witter R, Kuprov I, Lamley JM, Oss A, Lewandowski JR, Samoson A. 1H line width dependence on MAS speed in solid state NMR - Comparison of experiment and simulation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 291:32-39. [PMID: 29679841 DOI: 10.1016/j.jmr.2018.04.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 06/08/2023]
Abstract
Recent developments in magic angle spinning (MAS) technology permit spinning frequencies of ≥100 kHz. We examine the effect of such fast MAS rates upon nuclear magnetic resonance proton line widths in the multi-spin system of β-Asp-Ala crystal. We perform powder pattern simulations employing Fokker-Plank approach with periodic boundary conditions and 1H-chemical shift tensors calculated using the bond polarization theory. The theoretical predictions mirror well the experimental results. Both approaches demonstrate that homogeneous broadening has a linear-quadratic dependency on the inverse of the MAS spinning frequency and that, at the faster end of the spinning frequencies, the residual spectral line broadening becomes dominated by chemical shift distributions and susceptibility effects even for crystalline systems.
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Affiliation(s)
- Ulrich Sternberg
- Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany; COSMOS GbR, Jena, Germany.
| | - Raiker Witter
- School of Information Technologies, Tallinn University of Technology, Tallinn, Estonia; Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany; NMR Institute MTÜ, Tallinn, Estonia
| | - Ilya Kuprov
- School of Chemistry, University of Southampton, UK
| | | | - Andres Oss
- School of Information Technologies, Tallinn University of Technology, Tallinn, Estonia; NMR Institute MTÜ, Tallinn, Estonia
| | | | - Ago Samoson
- School of Information Technologies, Tallinn University of Technology, Tallinn, Estonia; NMR Institute MTÜ, Tallinn, Estonia
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4
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Mote KR, Agarwal V, Madhu PK. Five decades of homonuclear dipolar decoupling in solid-state NMR: Status and outlook. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2016; 97:1-39. [PMID: 27888838 DOI: 10.1016/j.pnmrs.2016.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 06/06/2023]
Abstract
It has been slightly more than fifty years since the first homonuclear spin decoupling scheme, Lee-Goldburg decoupling, was proposed for removing homonuclear dipolar interactions in solid-state nuclear magnetic resonance. A family of such schemes has made observation of high-resolution NMR spectra of abundant spins possible in various applications in solid state. This review outlines the strategies used in this field and the future prospects of homonuclear spin decoupling in solid-state NMR.
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Affiliation(s)
- Kaustubh R Mote
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India
| | - P K Madhu
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 21 Brundavan Colony, Narsingi, Hyderabad 500 075, India; Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
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Brouwer DH, Horvath M. Minimizing the effects of RF inhomogeneity and phase transients allows resolution of two peaks in the (1)H CRAMPS NMR spectrum of adamantane. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 71:30-40. [PMID: 26483329 DOI: 10.1016/j.ssnmr.2015.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 09/23/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
One of the limiting factors to achieving highly resolved (1)H NMR spectra with (1)H homonuclear decoupling sequences is imperfections in the applied radiofrequency (RF) pulses, most notably phase transients and RF inhomogeneity. Through a series of simulations and solid-state NMR experiments, it is demonstrated that the combined effects of phase transients and RF inhomogeneity can be minimized by a combination of (i) restricting the sample to small volume of the rotor, (ii) by employing a super-cycled version of the DUMBO decoupling sequence, and (iii) by carefully adjusting the probe tuning such that the asymmetric component of phase transients is minimized. Under these optimal conditions, it was possible to clearly resolve two signals in the (1)H CRAMPS NMR spectrum of adamantane arising from the CH and CH2 protons in the molecule. It is proposed that adamantane could be a very useful setup sample for (1)H CRAMPS NMR as the two peaks are only resolved when the effects of RF inhomogeneity and phase transients are minimized.
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Affiliation(s)
- Darren H Brouwer
- Department of Chemistry, Redeemer University College, Ancaster, ON, Canada L9K 1J4.
| | - Matthew Horvath
- Department of Chemistry, Redeemer University College, Ancaster, ON, Canada L9K 1J4
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Iuga D, Holland D, Dupree R. A 3D experiment that provides isotropic homonuclear correlations of half-integer quadrupolar nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 246:122-129. [PMID: 25123541 DOI: 10.1016/j.jmr.2014.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 06/30/2014] [Accepted: 07/09/2014] [Indexed: 06/03/2023]
Abstract
Two 3D experiments, capable of producing enhanced resolution two-spin double-quantum (DQ) homonuclear correlations for half-integer quadrupolar nuclei, are described. The first uses a split-t1 MQMAS sequence followed by a sandwiched oR(3) symmetry-based dipolar recoupling sequence to directly excite DQ coherences. In this case an isotropic single-quantum (SQ) coherence starts the homonuclear DQ excitation. In the second experiment a single strong pulse is used to create triple quantum (TQ) coherence followed by a further single pulse conversion to zero-order before a non-sandwiched oR(3) DQ sequence. The first experiment is demonstrated using (87)Rb in RbNO3, with three Rb sites in a ∼5ppm range, and the second to (11)B in caesium triborate, CsB3O5, with two three-coordinated sites separated by ∼2ppm and one four-coordinated boron site. In both cases, all sites are clearly resolved and their connections observed. The second experiment has higher sensitivity and a good signal to noise is obtained in a reasonable time despite the long T1 relaxation time of (11)B in this material.
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Affiliation(s)
- Dinu Iuga
- Physics Department, University of Warwick, CV4 7AL Coventry, UK.
| | - Diane Holland
- Physics Department, University of Warwick, CV4 7AL Coventry, UK
| | - Ray Dupree
- Physics Department, University of Warwick, CV4 7AL Coventry, UK
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Shen M, Trébosc J, Lafon O, Pourpoint F, Hu B, Chen Q, Amoureux JP. Improving the resolution in proton-detected through-space heteronuclear multiple quantum correlation NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 245:38-49. [PMID: 24929867 DOI: 10.1016/j.jmr.2014.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 05/02/2014] [Accepted: 05/05/2014] [Indexed: 06/03/2023]
Abstract
Connectivities and proximities between protons and low-gamma nuclei can be probed in solid-state NMR spectroscopy using two-dimensional (2D) proton-detected heteronuclear correlation, through Heteronuclear Multiple Quantum Correlation (HMQC) pulse sequence. The indirect detection via protons dramatically enhances the sensitivity. However, the spectra are often broadened along the indirect F1 dimension by the decay of heteronuclear multiple-quantum coherences under the strong (1)H-(1)H dipolar couplings. This work presents a systematic comparison of the performances of various decoupling schemes during the indirect t1 evolution period of dipolar-mediated HMQC (D-HMQC) experiment. We demonstrate that (1)H-(1)H dipolar decoupling sequences during t1, such as symmetry-based schemes, phase-modulated Lee-Goldburg (PMLG) and Decoupling Using Mind-Boggling Optimization (DUMBO), provide better resolution than continuous wave (1)H irradiation. We also report that high resolution requires the preservation of (1)H isotropic chemical shifts during the decoupling sequences. When observing indirectly broad spectra presenting numerous spinning sidebands, the D-HMQC sequence must be fully rotor-synchronized owing to the rotor-synchronized indirect sampling and dipolar recoupling sequence employed. In this case, we propose a solution to reduce artefact sidebands caused by the modulation of window delays before and after the decoupling application during the t1 period. Moreover, we show that (1)H-(1)H dipolar decoupling sequence using Smooth Amplitude Modulation (SAM) minimizes the t1-noise. The performances of the various decoupling schemes are assessed via numerical simulations and compared to 2D (1)H-{(13)C} D-HMQC experiments on [U-(13)C]-L-histidine⋅HCl⋅H2O at various magnetic fields and Magic Angle spinning (MAS) frequencies. Great resolution and sensitivity enhancements resulting from decoupling during t1 period enable the detection of heteronuclear correlation between aliphatic protons and ammonium (14)N sites in L-histidine⋅HCl⋅H2O.
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Affiliation(s)
- Ming Shen
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China; UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - J Trébosc
- UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - O Lafon
- UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - F Pourpoint
- UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France
| | - Bingwen Hu
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
| | - Qun Chen
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
| | - J-P Amoureux
- Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China; UCCS, University Lille North of France, Villeneuve d'Ascq 59652, France.
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Bonhomme C, Gervais C, Laurencin D. Recent NMR developments applied to organic-inorganic materials. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 77:1-48. [PMID: 24411829 DOI: 10.1016/j.pnmrs.2013.10.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/17/2013] [Indexed: 06/03/2023]
Abstract
In this contribution, the latest developments in solid state NMR are presented in the field of organic-inorganic (O/I) materials (or hybrid materials). Such materials involve mineral and organic (including polymeric and biological) components, and can exhibit complex O/I interfaces. Hybrids are currently a major topic of research in nanoscience, and solid state NMR is obviously a pertinent spectroscopic tool of investigation. Its versatility allows the detailed description of the structure and texture of such complex materials. The article is divided in two main parts: in the first one, recent NMR methodological/instrumental developments are presented in connection with hybrid materials. In the second part, an exhaustive overview of the major classes of O/I materials and their NMR characterization is presented.
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Affiliation(s)
- Christian Bonhomme
- Laboratoire de Chimie de la Matière Condensée de Paris, UMR CNRS 7574, Université Pierre et Marie Curie, Paris 06, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.
| | - Christel Gervais
- Laboratoire de Chimie de la Matière Condensée de Paris, UMR CNRS 7574, Université Pierre et Marie Curie, Paris 06, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Danielle Laurencin
- Institut Charles Gerhardt de Montpellier, UMR5253, CNRS UM2 UM1 ENSCM, CC1701, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
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Lu X, Lafon O, Trébosc J, Thankamony ASL, Nishiyama Y, Gan Z, Madhu PK, Amoureux JP. Detailed analysis of the TIMES and TIMES0 high-resolution MAS methods for high-resolution proton NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 223:219-227. [PMID: 22985982 DOI: 10.1016/j.jmr.2012.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 07/19/2012] [Accepted: 07/22/2012] [Indexed: 06/01/2023]
Abstract
We analyze and compare the specifications of TIMES and TIMES(0) proton high-resolution NMR methods for solid-state samples. This comparison is performed in terms of resolution versus magic-angle spinning (MAS) spinning speed, ν(R), rf-field amplitude, ν(1), and tilt-angle for the effective rf-field, θ(p). The chemical-shift and homo-nuclear dipolar scaling factors are calculated for both methods. For all MAS speeds, the best resolution is always observed with rf-field of ν(1)≈120-130 kHz. At slow MAS speed (ν(R)≤10 kHz), the best resolution is observed for a tilt-angle of θ(P)≈90°. At moderate spinning speed (15≤ν(R)≤35 kHz), θ(P)≈55° gives the best resolution. At higher MAS speed (ν(R)≥60 kHz), with TIMES and TIMES(0) the best resolution is obtained for θ(P)≤40°; but we then recommend TIMES(0), owing to its simpler set-up. We also show that in addition to the usual high rf-field regime (ν(1)≈120-130 kHz), another low rf-regime (ν(1)≈40-50 kHz) exists at MAS speed higher than ν(R)≥60 kHz, which also gives a good (1)H resolution. This low rf-regime should be useful for multi-dimensional analyses of bio-molecules with (1)H detection under high-resolution, in order to limit the heating of the sample.
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Affiliation(s)
- Xingyu Lu
- UCCS (CNRS-8181), University Lille North of France, Villeneuve d'Ascq 59652, France
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10
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Nishiyama Y, Lu X, Trébosc J, Lafon O, Gan Z, Madhu PK, Amoureux JP. Practical choice of ¹H-¹H decoupling schemes in through-bond ¹H-{X} HMQC experiments at ultra-fast MAS. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 214:151-158. [PMID: 22130518 DOI: 10.1016/j.jmr.2011.10.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 10/05/2011] [Accepted: 10/28/2011] [Indexed: 05/31/2023]
Abstract
Three (1)H-(1)H homonuclear dipolar decoupling schemes for (1)H indirect detection measurements at very fast MAS are compared. The sequences require the following conditions: (i) being operable at very fast MAS, (ii) a long T(2)(') value, (iii) a large scaling factor, (iv) a small number of adjustable parameters, (v) an acquisition window, (vi) a low rf-power requirement, and (vii) a z-rotation feature. To satisfy these conditions a modified sequence named TIlted Magic-Echo Sandwich with zero degree sandwich pulse (TIMES(0)) is introduced. The basic elements of TIMES(0) consist of one sampling window and two phase-ramped irradiations, which realize alternating positive and negative 360° rotations of (1)H magnetization around an effective field tilted with an angle θ from the B(0) axis. The TIMES(0) sequence benefits from very large chemical shift scaling factors at ultra-fast MAS that reach κ(cs)=0.90 for θ=25° at ν(r)=80kHz MAS and only four adjustable parameters, resulting in easy setup. Long κ(cs)T(2)(') values, where T(2)(') is a irreversible proton transverse relaxation time, greatly enhance the sensitivity in (1)H-{(13)C} through-bond J-HMQC (Heteronuclear Multiple-Quantum Coherence) measurements with (1)H-(1)H decoupling during magnetization transfer periods. Although similar sensitivity can be obtained with through-space D-HMQC sequences, in which (13)C-(1)H dipolar interactions are recoupled, J-HMQC experiments incorporating (1)H-(1)H decoupling benefit from lower t(1)-noise, more uniform excitation of both CH, CH(2) and CH(3) moieties, and easier identification of through-bond connectivities.
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Affiliation(s)
- Yusuke Nishiyama
- JEOL RESONANCE Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
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A tunable homonuclear dipolar decoupling scheme for high-resolution proton NMR of solids from slow to fast magic-angle spinning. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2010.12.070] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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12
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Wang Q, Lu X, Lafon O, Trébosc J, Deng F, Hu B, Chen Q, Amoureux JP. Measurement of 13C–1H dipolar couplings in solids by using ultra-fast magic-angle spinning NMR spectroscopy with symmetry-based sequences. Phys Chem Chem Phys 2011; 13:5967-73. [DOI: 10.1039/c0cp01907k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Paul S, Schneider D, Madhu PK. 1H Homonuclear dipolar decoupling using symmetry-based pulse sequences at ultra fast magic-angle spinning frequencies. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 206:241-245. [PMID: 20727798 DOI: 10.1016/j.jmr.2010.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 07/18/2010] [Accepted: 07/19/2010] [Indexed: 05/29/2023]
Abstract
We demonstrate here the application of symmetry-based pulse sequences for homonuclear dipolar decoupling in solid-state NMR at magic-angle spinning (MAS) frequencies up to 65 kHz using moderate radiofrequency (RF) amplitudes. Theoretical arguments favouring the requirement of low RF amplitudes at high MAS frequencies are given for these sequences. A comparison with wPMLGmmxx¯ is given at 65 kHz of MAS frequency to emphasise that the symmetry-based pulse sequences have a lower RF amplitude requirement at high MAS frequencies.
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Affiliation(s)
- Subhradip Paul
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
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Salager E, Dumez JN, Stein RS, Steuernagel S, Lesage A, Elena-Herrmann B, Emsley L. Homonuclear dipolar decoupling with very large scaling factors for high-resolution ultrafast magic angle spinning 1H solid-state NMR spectroscopy. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.08.038] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Demers JP, Vijayan V, Becker S, Lange A. Tailored low-power cross-polarization under fast magic-angle spinning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 205:216-23. [PMID: 20570194 DOI: 10.1016/j.jmr.2010.04.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 04/29/2010] [Indexed: 05/10/2023]
Abstract
High static magnetic fields and very fast magic-angle spinning (MAS) promise to improve resolution and sensitivity of solid-state NMR experiments. The fast MAS regime has permitted the development of low-power cross-polarization schemes, such as second-order cross-polarization (SOCP), which prevent heat deposition in the sample. Those schemes are however limited in bandwidth, as weak radio-frequency (RF) fields only cover a small chemical shift range for rare nuclei (e.g. (13)C). Another consideration is that the efficiency of cross-polarization is very sensitive to magnetization decay that occurs during the spin-lock pulse on the abundant nuclei (e.g. (1)H). Having characterized this decay in glutamine at 60 kHz MAS, we propose two complementary strategies to tailor cross-polarization to desired spectral regions at low RF power. In the case of multiple sites with small chemical shift dispersion, a larger bandwidth for SOCP is obtained by slightly increasing the RF power while avoiding recoupling conditions that lead to fast spin-lock decay. In the case of two spectral regions with large chemical shift offset, an extension of the existing low-power schemes, called MOD-CP, is introduced. It consists of a spin-lock on (1)H and an amplitude-modulated spin-lock on the rare nucleus. The range of excited chemical shifts is assessed by experimental excitation profiles and numerical simulation of an I(2)S spin system. All SOCP-based schemes exhibit higher sensitivity than high-power CP schemes, as demonstrated on solid (glutamine) and semi-solid (hydrated, micro-crystalline ubiquitin) samples.
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Affiliation(s)
- Jean-Philippe Demers
- Max Planck Institute for Biophysical Chemistry, Solid-state NMR, Göttingen 37077, Germany
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16
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Paul S, Thakur RS, Levitt MH, Madhu PK. 1H homonuclear dipolar decoupling using rotor-synchronised pulse sequences: towards pure absorption phase spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 205:269-275. [PMID: 20570540 DOI: 10.1016/j.jmr.2010.05.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Revised: 05/11/2010] [Accepted: 05/13/2010] [Indexed: 05/29/2023]
Abstract
We demonstrate a pulse sequence using symmetry-based rotor-synchronised RN(n)(nu) sequences for homonuclear dipolar decoupling that achieves pure absorption phase high-resolution (1)H spectra in solid-state NMR. This sequence is compared with the phase-modulated Lee-Goldburg scheme. Experimental results are shown for samples of glycine and L-histidine.HCl.H(2)O for magic-angle-spinning frequencies in the range of 14-30 kHz and at two different magnetic fields.
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Affiliation(s)
- Subhradip Paul
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
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Lafon O, Wang Q, Hu B, Vasconcelos F, Trébosc J, Cristol S, Deng F, Amoureux JP. Indirect detection via spin-1/2 nuclei in solid state NMR spectroscopy: application to the observation of proximities between protons and quadrupolar nuclei. J Phys Chem A 2010; 113:12864-78. [PMID: 19905016 DOI: 10.1021/jp906099k] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a comprehensive comparison of through-space heteronuclear correlation techniques for solid state NMR, combining indirect detection and single-channel recoupling method. These techniques, named D-HMQC and D-HSQC, do not suffer from dipolar truncation and can be employed to correlate quadrupolar nuclei with spin-1/2 nuclei. The heteronuclear dipolar couplings are restored under magic-angle spinning by applying supercycled symmetry-based pulse sequences (SR412) or simultaneous frequency and amplitude modulation (SFAM). The average Hamiltonian theory (AHT) of these recoupling methods is developed. These results are applied to analyze the performances of D-HMQC and D-HSQC sequences. It is shown that, whatever the magnitude of spin interations, D-HMQC experiment offers larger efficiency and higher robustness than D-HSQC. Furthermore, the spectral resolution in both dimensions of proton detected two-dimensional D-HMQC and D-HSQC spectra can be enhanced by applying recently introduced symmetry-based homonuclear dipolar decoupling schemes that cause a z-rotation of the spins. This is demonstrated by 1H-13C and 1H-23Na correlation experiments on l-histidine and NaH2PO4, respectively. The two-dimensional heteronuclear 1H-23Na correlation spectrum yields the assignment of 23Na resonances of NaH2PO4. This assignment is corroborated by first-principles calculations.
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Affiliation(s)
- Olivier Lafon
- Unité de Catalyse et de Chimie du Solide (UCCS), UMR CNRS 8181, Ecole Nationale Supérieure de Chimie de Lille, Université de Lille 1, Batiment C7, B.P. 90108, 59652 Villeneuve d'Ascq Cedex, France
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Cavadini S, Vitzthum V, Ulzega S, Abraham A, Bodenhausen G. Line-narrowing in proton-detected nitrogen-14 NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 202:57-63. [PMID: 19853485 DOI: 10.1016/j.jmr.2009.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 09/28/2009] [Accepted: 09/28/2009] [Indexed: 05/28/2023]
Abstract
In solids spinning at the magic angle, the indirect detection of single-quantum (SQ) and double-quantum (DQ) (14)N spectra (I=1) via spy nuclei S=1/2 such as protons can be achieved in the manner of heteronuclear single- or multiple-quantum correlation (HSQC or HMQC) spectroscopy. The HMQC method relies on the excitation of two-spin coherences of the type T(11)(I)T(11)(S) and T(21)(I)T(11)(S) at the beginning of the evolution interval t(1). The spectra obtained by Fourier transformation from t(1) to omega(1) may be broadened by the homogenous decay of the transverse terms of the spy nuclei S. This broadening is mostly due to homonuclear dipolar S-S' interactions between the proton spy nuclei. In this work we have investigated the possibility of inserting rotor-synchronized symmetry-based C or R sequences and decoupling schemes such as Phase-Modulated Lee-Goldburg (PMLG) sequences in the evolution period. These schemes reduce the homonuclear proton-proton interactions and lead to an enhancement of the resolution of both SQ and DQ proton-detected (14)N HMQC spectra. In addition, we have investigated the combination of HSQC with symmetry-based sequences and PMLG and shown that the highest resolution in the (14)N dimension is achieved by using HSQC in combination with symmetry-based sequences of the R-type. We show improvements in resolution in samples of l-alanine and the tripeptide ala-ala-gly (AAG). In particular, for l-alanine the width of the (14)N SQ peak is reduced from 2 to 1.2 kHz, in agreement with simulations. We report accurate measurements of quadrupolar coupling constants and asymmetry parameters for amide (14)N in AAG peptide bonds.
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Affiliation(s)
- Simone Cavadini
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Leskes M, Madhu PK, Vega S. Why does PMLG proton decoupling work at 65kHz MAS? JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 199:208-213. [PMID: 19482494 DOI: 10.1016/j.jmr.2009.05.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 05/03/2009] [Accepted: 05/04/2009] [Indexed: 05/27/2023]
Abstract
Schemes such as phase-modulated Lee-Goldburg (PMLG) for homonuclear dipolar decoupling have been shown to yield high-resolution (1)H spectra at high magic-angle spinning (MAS) frequencies of 50-70kHz. This is at variance to the commonly held notion that these methods require MAS frequencies not comparable to the cycle frequencies of the pulse schemes. Here, a theoretical argument, based on bimodal Floquet theory, is presented to explain this aspect together with conditions where PMLG type of schemes may be successful at high MAS frequencies.
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Affiliation(s)
- Michal Leskes
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
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Bradley JP, Tripon C, Filip C, Brown SP. Determining relative proton-proton proximities from the build-up of two-dimensional correlation peaks in 1H double-quantum MAS NMR: insight from multi-spin density-matrix simulations. Phys Chem Chem Phys 2009; 11:6941-52. [PMID: 19652828 DOI: 10.1039/b906400a] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The build-up of intensity-as a function of the number, n(rcpl), of POST-C7 elements used for the excitation and reconversion of double-quantum (DQ) coherence (DQC)-is analysed for the fifteen distinct DQ correlation peaks that are observed experimentally for the eight separate (1)H resonances in a (1)H (500 MHz) DQ CRAMPS solid-state (12.5 kHz MAS) NMR spectrum of the dipeptide beta-AspAla (S. P. Brown, A. Lesage, B. Elena, and L. Emsley, J. Am. Chem. Soc., 2004, 126, 13230). The simulation in SPINEVOLUTION (M. Veshtort and R. G. Griffin, J. Magn. Reson., 2006, 178, 248) of t(1) ((1)H DQ evolution) FIDs for clusters of eight dipolar-coupled protons gives separate simulated (1)H DQ build-up curves for the CH(2)(a), CH(2)(b), CH(Asp), CH(Ala), NH and OH (1)H single-quantum (SQ) (1)H resonances. An analysis of both the simulated and experimental (1)H DQ build-up leads to the following general observations: (i) considering the build-up of (1)H DQ peaks at a particular SQ frequency, maximum intensity is observed for the DQC corresponding to the shortest H-H distance; (ii) for the maximum intensity (1)H DQ peak at a particular SQ frequency, the recoupling time for the observed maximum intensity depends on the corresponding H-H distance, e.g., maximum intensity for the CH(2)(a)-CH(2)(b) (H-H distance = 1.55 A) and OH-CH(Asp) (H-H distance = 2.49 A) DQ peaks is observed at n(rcpl) = 2 and 3, respectively; (iii) for DQ peaks involving a CH(2) proton at a non-CH(2) SQ frequency, there is much reduced intensity and a maximum intensity at a short recoupling time; (iv) for the other lower intensity (1)H DQ peaks at a particular SQ frequency, maximum intensity is observed for the same (or close to the same) recoupling time, but the relative intensity of the DQ peaks is a reliable indicator of the relative H-H distance-the ratio of the maximum intensities for the peaks at the CH(Ala) SQ frequency due to the two DQCs with the NH and OH protons are found to be approximately in the ratio of the squares of the corresponding dipolar coupling constants. While the simulated (1)H DQ build-up curves reproduce most of the features of the experimental curves, maximum intensity is often observed at a longer recoupling time in simulations. In this respect, simulations for two to eight spins show a trend towards a faster decay for an increasing number of considered spins. Finally, simulations show that increasing either the Larmor frequency (to 1 GHz) or the MAS frequency (to 125 kHz) does not lead to changes in the marked differences between the (1)H DQ build-up curves at the CH(Asp) SQ frequency for DQCs to the CH(2)(a) and OH protons that correspond to similar H-H distances (2.39 A and 2.49 A, respectively).
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Mafra L, Coelho C, Siegel R, Rocha J. Assessing the performance of windowed 1H CRAMPS methods, on biological solids, at high-field and MAS up to 35 kHz. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 197:20-27. [PMID: 19101183 DOI: 10.1016/j.jmr.2008.11.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 11/05/2008] [Accepted: 11/18/2008] [Indexed: 05/27/2023]
Abstract
The performance of various high-resolution 1D (1)H CRAMPS pulse schemes at moderate and high static magnetic fields (400 MHz and 800 (1)H Larmor frequencies) and spinning rates up to 35 kHz, using state-of-the-art electronics is compared. The performance of the (1)H windowed acquisition decoupling schemes, wDUMBO, wPMLG3 and wSAM3 is investigated using their effective z-rotation variants on glycine and other small biological molecules, tripeptide reduced glutathione and nucleoside uridine. (1)H CRAMPS spectra, recorded with windowed (1)H-(1)H decoupling methods and fast MAS (35 kHz) and high-field are reported for the first time. (1)H spectra exhibiting outstanding resolution and completely free from any artifact are also shown. The effect on spectra quality of the decoupling rf cycle and rotor periods ratio (tau(C)/tau(R)) and the power requirements needed for each windowed (1)H CRAMPS methods are discussed.
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Affiliation(s)
- Luís Mafra
- Department of Chemistry, CICECO, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
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Lesage A. Recent advances in solid-state NMR spectroscopy of spin I = 1/2 nuclei. Phys Chem Chem Phys 2009; 11:6876-91. [DOI: 10.1039/b907733m] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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