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Sasaki A, Trébosc J, Nagashima H, Amoureux JP. On the applicability of cosine-modulated pulses for high-resolution solid-state NMR of quadrupolar nuclei with spin > 3/2. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2023; 125:101863. [PMID: 37060799 DOI: 10.1016/j.ssnmr.2023.101863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 06/11/2023]
Abstract
In MQMAS-based high-resolution solid-state NMR experiments of half-integer spin quadrupolar nuclei, the high radiofrequency (RF) field requirement for the MQ excitation and conversion steps with two hard-pulses is often a sensitivity limiting factor in many practical applications. Recently, the use of two cosine-modulated (cos) low-power (lp) pulses, lasting one-rotor period each, was successfully introduced for efficient MQ excitation and conversion of spin-3/2 nuclei with a reduced RF amplitude. In this study, we extend our previous investigations of spin-3/2 nuclei to systems with higher spin values and discuss the applicability of coslp-MQ excitation and conversion in MQMAS and MQ-HETCOR experiments under slow and fast spinning conditions. For the numerical simulations and experiments we used a moderate magnetic field of 14.1 T. Two spin-5/2 nuclei (85Rb and 27Al) are mainly employed with a large variety of CQ values, but we show that the practical set up is also available for higher spin values, such as spin-9/2 with 93Nb in Cs4Nb11O30. We demonstrate for nuclei with spin value larger than 3/2 a preferential use of coslp-MQ acquisition for low-gamma nuclei and/or large CQ values with a much reduced RF-field with respect to that of hard-pulses used with conventional methods.
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Affiliation(s)
- Akiko Sasaki
- Bruker Japan K.K, 3-9, Moriya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa, 221-0022, Japan; Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
| | - Julien Trébosc
- Univ. Lille, CNRS, INRAE, Centrale Lille, Univ. Artois, FR 2638 - IMEC - Institut Michel-Eugène Chevreul, F-59000, Lille, France
| | - Hiroki Nagashima
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
| | - Jean-Paul Amoureux
- Bruker Biospin, 34 rue de l'industrie, F-67166, Wissembourg, France; Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unit of Catalysis and Chemistry of Solids, F-59000, Lille, France.
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2
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Sasaki A, Trébosc J, Nagashima H, Amoureux JP. Practical considerations on the use of low RF-fields and cosine modulation in high-resolution NMR of I = 3/2 spin quadrupolar nuclei in solids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 345:107324. [PMID: 36370548 DOI: 10.1016/j.jmr.2022.107324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
Despite its ease in experimental set up, the low sensitivity of MQMAS experiments is often a limiting factor in many practical applications. This is mainly due to the large radiofrequency (RF) field requirement of the two short hard-pulses often used for the optimum MQ excitation and conversion steps. Very recently, two novel MQMAS experiments have been proposed for I = 3/2 nuclei, namely lp-MQMAS and coslp-MQMAS, enabling an efficient MQ excitation/conversion with a reduced RF requirement, by utilizing two long pulses lasting one rotor period each, with or without cosine modulation. In this study, we focus on the practical considerations of these new methods and discuss their pros and cons to elucidate their appropriate use under both moderate and fast spinning conditions. Using four I = 3/2 (87Rb, 71Ga, 35Cl and 23Na) nuclei at a moderate magnetic field (B0 = 14.1 T), we show the superior use of these experiments, especially for samples with large CQ values and/or low-gamma nuclei. Compared to all other existing sequences, the coslp-MQMAS method with initial WURST signal enhancement is the most robust, efficient and resolved high-resolution 2D method for spin 3/2 nuclei. Furthermore, using {23Na}-1H spin systems, we demonstrate the sensitivity advantage of the WURST coslp-MQ-HETCOR acquisition upon 1H detection and fast MAS conditions.
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Affiliation(s)
- Akiko Sasaki
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan; Bruker Japan K.K., 3-9, Moriya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa 221-0022, Japan
| | - Julien Trébosc
- Univ. Lille, CNRS, INRAE, Centrale Lille, Univ. Artois, FR 2638 - IMEC - Institut Michel-Eugène Chevreul, F-59000 Lille, France
| | - Hiroki Nagashima
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Jean-Paul Amoureux
- Bruker Biospin, 34 rue de l'industrie, F-67166 Wissembourg, France; Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unit of Catalysis and Chemistry of Solids, F-59000 Lille, France
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3
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Bansal M, Ramachandran R. Theory of radio-frequency pulses on periodically driven three-level systems: challenges and perspectives. Phys Chem Chem Phys 2022; 24:29092-29111. [DOI: 10.1039/d2cp03906k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nuances of multiple-quantum transitions in periodically driven systems is discussed through analytical methods based on time propagators derived from Floquet theory.
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Affiliation(s)
- Mohit Bansal
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Manauli P.O. Box-140306, Mohali, Punjab, India
| | - Ramesh Ramachandran
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Manauli P.O. Box-140306, Mohali, Punjab, India
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4
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Sasaki A, Tsutsumi Y, Amoureux JP. Accelerating high-resolution NMR of half-integer quadrupolar nuclei in solids: SPAM-MQMAS and SPAM-STMAS. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2020; 108:101668. [PMID: 32645557 DOI: 10.1016/j.ssnmr.2020.101668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/07/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
In solid-state NMR, multiple-quantum MAS (MQMAS) and satellite-transition MAS (STMAS) experiments are well-established techniques to obtain high-resolution spectra of half-integer quadrupolar nuclei. In 2004 and 2005, a soft-pulse-added-mixing (SPAM) concept was introduced by Gan and Amoureux to enhance the S/N ratio of MQMAS and STMAS experiments. Despite their robustness and simplicity, SPAM approaches have not yet been widely applied. Here, we further exploit SPAM concepts for sensitivity enhancement upon acquisition of two-dimensional MQMAS and STMAS spectra and also establish a general procedure upon implementation of SPAM-MQMAS and SPAM-STMAS NMR. Its effectiveness and ease in experimental setup are demonstrated using simulations and experiments performed on I = 3/2 (23Na, 87Rb), 5/2 (27Al, 85Rb) and 9/2 (93Nb) nuclei with a variety of quadrupolar coupling constants (CQ). Compared to the conventional z-filter methods, sensitivity enhancements in between 2 and 4 are achievable with SPAM. We recommend to use SPAM with a ratio of 4:1 for the number of echoes and antiechoes to safely maximize the sensitivity and resolution simultaneously. In addition, a comparison of the experimental approaches is made in the context of SPAM-MQMAS and SPAM-STMAS NMR with respect to repetition delay and spinning frequency, aiming to discuss the precautions upon making a judicious choice of high-resolution NMR methods of half-integer quadrupolar nuclei.
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Affiliation(s)
- Akiko Sasaki
- Bruker Japan K.K, 3-9, Moriya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa, 221-0022, Japan
| | - Yu Tsutsumi
- Bruker Japan K.K, 3-9, Moriya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa, 221-0022, Japan
| | - Jean-Paul Amoureux
- Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 - UCCS - Unit of Catalysis and Chemistry of Solids, F-59000, Lille, France; Bruker Biospin, 34 rue de l'industrie, F-67166, Wissembourg, France; RIKEN RSC NMR Science and Development Division, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa, 230-0045, Japan.
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5
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Sørensen JJ, Nyemann JS, Motzoi F, Sherson J, Vosegaard T. Optimization of pulses with low bandwidth for improved excitation of multiple-quantum coherences in NMR of quadrupolar nuclei. J Chem Phys 2020; 152:054104. [DOI: 10.1063/1.5141384] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jens Jakob Sørensen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Jacob Søgaard Nyemann
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
- Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Felix Motzoi
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
- Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), D-52425 Jülich, Germany
| | - Jacob Sherson
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Thomas Vosegaard
- Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
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Colaux H, Dawson DM, Ashbrook SE. Investigating FAM-N pulses for signal enhancement in MQMAS NMR of quadrupolar nuclei. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 84:89-102. [PMID: 28131696 DOI: 10.1016/j.ssnmr.2017.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 06/06/2023]
Abstract
Although a popular choice for obtaining high-resolution solid-state NMR spectra of quadrupolar nuclei, the inherently low sensitivity of the multiple-quantum magic-angle spinning (MQMAS) experiment has limited its application for nuclei with low receptivity or when the available sample volume is limited. A number of methods have been introduced in the literature to attempt to address this problem. Recently, we have introduced an alternative, automated approach, based on numerical simulations, for generating amplitude-modulated pulses (termed FAM-N pulses) to enhance the efficiency of the triple- to single-quantum conversion step within MQMAS. This results in efficient pulses that can be used without experimental reoptimisation, ensuring that this method is particularly suitable for challenging nuclei and systems. In this work, we investigate the applicability of FAM-N pulses to a wider variety of systems, and their robustness under more challenging experimental conditions. These include experiments performed under fast MAS, nuclei with higher spin quantum numbers, samples with multiple distinct sites, low-γ nuclei and nuclei subject to large quadrupolar interactions.
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Affiliation(s)
- Henri Colaux
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
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7
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Wi S, Schurko R, Frydman L. 1H–2H cross-polarization NMR in fast spinning solids by adiabatic sweeps. J Chem Phys 2017; 146:104201. [DOI: 10.1063/1.4976980] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Sungsool Wi
- National High Magnetic Field Laboratory, Tallahassee, Florida 32304, USA
| | - Robert Schurko
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor N9B 3P4, Ontario, Canada
| | - Lucio Frydman
- National High Magnetic Field Laboratory, Tallahassee, Florida 32304, USA
- Department of Chemical Physics, Weizmann Institute of Sciences, Rehovot 76100, Israel
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8
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Koczor B, Rohonczy J. A novel pulse scheme for multiple quantum excitation, SFAM to enhance the sensitivity of MQMAS experiments. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2016; 74-75:1-9. [PMID: 26926400 DOI: 10.1016/j.ssnmr.2016.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/11/2016] [Accepted: 02/17/2016] [Indexed: 06/05/2023]
Abstract
The basic MQMAS sequence consists of two hard pulses, one excites the equilibrium population to MQ (Multiple Quantum) coherence, and the other converts back to detectable coherence after some evolution time t1 (Medek et al., 1995). Unfortunately the MQ excitation and conversion processes are very inefficient due to the nonlinear nature of MQ processes. MQ conversion (converting MQ back to detectable coherence) efficiency can significantly be enhanced with DFS (Double Frequency Sweep) or FAM (Fast Amplitude Modulation) type pulses instead of rectangular pulse irradiation (Goldbourt and Madhu, 2002). In contrary to conversion, it is more challenging to enhance MQ excitation in MQMAS experiments, since most methods result in distorted lineshapes (Goldbourt and Madhu, 2002; Lim and Grey, 1998). In the present work MQ excitation of single crystals was studied, and the understanding of the process led to a principle, which was extended to the excitation of powder samples as well. The resulting method was implemented into the MQMAS sequence to enhance MQ excitation of powder samples under MAS condition. The new sequence called SFAM (Shifted Fast Amplitude Modulation) can provide high enhancements at low RF powers (ϵ>4 at νrf=40 kHz) compared to rectangular pulses. Although simulated lineshapes of SFAM predict only minor deviations from ideal lineshapes, experimentally obtained lineshapes along the anisotropic dimension show rather strong distortions. SFAM is relatively simple to optimize, and shows robustness with respect to the miscalibration or inhomogeneity of the RF power as well as to other parameters of the pulse scheme. A good agreement was found between numerically and experimentally optimized parameters.
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Affiliation(s)
- Bálint Koczor
- Eötvös Loránd University, Department of Inorganic Chemistry, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
| | - János Rohonczy
- Eötvös Loránd University, Department of Inorganic Chemistry, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary.
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9
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Shen M, Trébosc J, Lafon O, Gan Z, Pourpoint F, Hu B, Chen Q, Amoureux JP. Solid-state NMR indirect detection of nuclei experiencing large anisotropic interactions using spinning sideband-selective pulses. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 72:104-117. [PMID: 26411981 DOI: 10.1016/j.ssnmr.2015.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/04/2015] [Accepted: 09/04/2015] [Indexed: 06/05/2023]
Abstract
Under Magic-Angle Spinning (MAS), a long radio-frequency (rf) pulse applied on resonance achieves the selective excitation of the center-band of a wide NMR spectrum. We show herein that these rf pulses can be applied on the indirect channel of Hetero-nuclear Multiple-Quantum Correlation (HMQC) sequences, which facilitate the indirect detection via spin-1/2 isotopes of nuclei exhibiting wide spectra. Numerical simulations show that this indirect excitation method is applicable to spin-1/2 nuclei experiencing a large chemical shift anisotropy, as well as to spin-1 isotopes subject to a large quadrupole interaction, such as (14)N. The performances of the long pulses are analyzed by the numerical simulations of scalar-mediated HMQC (J-HMQC) experiments indirectly detecting spin-1/2 or spin-1 nuclei, as well as by dipolar-mediated HMQC (D-HMQC) experiments achieving indirect detection of (14)N nuclei via (1)H in crystalline γ-glycine and N-acetyl-valine samples at a MAS frequency of 60kHz. We show on these solids that for the acquisition of D-HMQC spectra between (1)H and (14)N nuclei, the efficiency of selective moderate excitation with long-pulses at the (14)N Larmor frequency, ν0((14)N), is comparable to those with strong excitation pulses at ν0((14)N) or 2ν0((14)N) frequencies, given the rf field delivered by common solid-state NMR probes. Furthermore, the D-HMQC experiments also demonstrate that the use of long pulses does not produce significant spectral distortions along the (14)N dimension. In summary, the use of center-band selective weak pulses is advantageous for HMQC experiments achieving the indirect detection of wide spectra since it (i) requires a moderate rf field, (ii) can be easily optimized, (iii) displays a high robustness to CSAs, offsets, rf-field inhomogeneities, and fluctuations in MAS frequency, and (iv) is little dependent on the quadrupolar coupling constant.
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Affiliation(s)
- Ming Shen
- UCCS, CNRS, UMR 8181, University of Lille, Villeneuve d'Ascq 59652, France; Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
| | - Julien Trébosc
- UCCS, CNRS, UMR 8181, University of Lille, Villeneuve d'Ascq 59652, France
| | - Olivier Lafon
- UCCS, CNRS, UMR 8181, University of Lille, Villeneuve d'Ascq 59652, France.
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance, NHMFL, Tallahassee, FL 32310, USA
| | | | - 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
| | - Jean-Paul Amoureux
- UCCS, CNRS, UMR 8181, University of Lille, Villeneuve d'Ascq 59652, France; Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China.
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10
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Vosegaard T. jsNMR: an embedded platform-independent NMR spectrum viewer. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:285-290. [PMID: 25641013 DOI: 10.1002/mrc.4195] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/28/2014] [Accepted: 11/07/2014] [Indexed: 06/04/2023]
Abstract
jsNMR is a lightweight NMR spectrum viewer written in JavaScript/HyperText Markup Language (HTML), which provides a cross-platform spectrum visualizer that runs on all computer architectures including mobile devices. Experimental (and simulated) datasets are easily opened in jsNMR by (i) drag and drop on a jsNMR browser window, (ii) by preparing a jsNMR file from the jsNMR web site, or (iii) by mailing the raw data to the jsNMR web portal. jsNMR embeds the original data in the HTML file, so a jsNMR file is a self-transforming dataset that may be exported to various formats, e.g. comma-separated values. The main applications of jsNMR are to provide easy access to NMR data without the need for dedicated software installed and to provide the possibility to visualize NMR spectra on web sites.
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Affiliation(s)
- Thomas Vosegaard
- Center for Insoluble Protein Structures, Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, 8000, Aarhus C, Denmark
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Fernandez C, Pruski M. Probing quadrupolar nuclei by solid-state NMR spectroscopy: recent advances. Top Curr Chem (Cham) 2011; 306:119-88. [PMID: 21656101 DOI: 10.1007/128_2011_141] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Solid-state nuclear magnetic resonance (NMR) of quadrupolar nuclei has recently undergone remarkable development of capabilities for obtaining structural and dynamic information at the molecular level. This review summarizes the key achievements attained during the last couple of decades in solid-state NMR of both integer spin and half-integer spin quadrupolar nuclei. We provide a concise description of the first- and second-order quadrupolar interactions, and their effect on the static and magic angle spinning (MAS) spectra. Methods are explained for efficient excitation of single- and multiple-quantum coherences, and acquisition of spectra under low- and high-resolution conditions. Most of all, we present a coherent, comparative description of the high-resolution methods for half-integer quadrupolar nuclei, including double rotation (DOR), dynamic angle spinning (DAS), multiple-quantum magic angle spinning (MQMAS), and satellite transition magic angle spinning (STMAS). Also highlighted are methods for processing and analysis of the spectra. Finally, we review methods for probing the heteronuclear and homonuclear correlations between the quadrupolar nuclei and their quadrupolar or spin-1/2 neighbors.
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Hajjar R, Millot Y, Man PP. Phase cycling in MQMAS sequences for half-integer quadrupole spins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2010; 57:306-342. [PMID: 20667403 DOI: 10.1016/j.pnmrs.2010.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 05/11/2010] [Indexed: 05/29/2023]
Affiliation(s)
- Redouane Hajjar
- UPMC Univ Paris 06, FRE 3230, Laboratoire RMN des Matériaux Nanoporeux, 4 Place Jussieu, F-75005 Paris, France
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Millot Y, Hajjar R, Man PP. NMR cogwheel phase cycling determination with web tools: amplitude-modulated z-filter MQMAS sequence. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2010; 38:19-26. [PMID: 20580537 DOI: 10.1016/j.ssnmr.2010.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 05/28/2010] [Accepted: 06/08/2010] [Indexed: 05/04/2023]
Abstract
Our recent method based on the use of web tools (XML and XSLT) for constructing cogwheel phase cycles is extended to the selection of two symmetrical coherence transfer pathways in the case of an amplitude-modulated z-filter MQMAS sequence. For all spins (I=3/2, 5/2, 7/2 and 9/2) and all MQ experiments we compare cogwheel phase cycling with the traditional "nested" phase cycling. The principal difference in the number of phase cycling steps lies in the use of digitizer phase. For nested phase cycling, this number depends on the use of reference receiver phase or digitizer phase, while cogwheel phase cycling does not. As an illustration we consider the case of a+/-3QMAS experiment for spin I=7/2 system applied to cobalt-59 in [Co(NH3)6]Cl3 powder. We also explore the selection of two non-symmetrical coherence transfer pathways in the case of an amplitude-modulated shifted-echo MQMAS sequence.
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Affiliation(s)
- Yannick Millot
- UPMC, Univ. Paris 06, UMR 7142, Laboratoire SIEN, 4 Place Jussieu, F-75005, Paris, France.
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Edén M. Two-dimensional MAS NMR correlation protocols involving double-quantum filtering of quadrupolar spin-pairs. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 204:99-110. [PMID: 20202872 DOI: 10.1016/j.jmr.2010.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Revised: 02/07/2010] [Accepted: 02/09/2010] [Indexed: 05/28/2023]
Abstract
Three two-dimensional (2D) NMR homonuclear correlation techniques invoking double-quantum (2Q) filtration of the central transitions of half-integer spins are evaluated numerically and experimentally. They correlate directly detected single-quantum (1Q) coherences in the t(2) domain with either of 1Q, two-spin 2Q or single-spin multiple-quantum coherence-evolutions in the indirect (t(1)) dimension. We employ experimental (23)Na and (27)Al NMR on sodium sulfite and the natural mineral sillimanite (SiAl(2)O(5)), in conjunction with simulated 2D spectra from pairs of dipolar-recoupled spins-3/2 and 5/2 at different external magnetic fields, to compare the correlation strategies from the viewpoints of 2D spectral resolution, signal sensitivity, implementational aspects and their relative merits for establishing internuclear proximities and quadrupolar tensor orientations.
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Affiliation(s)
- Mattias Edén
- Physical Chemistry Division, Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
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15
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Ashbrook SE, Wimperis S. Spin-locking of half-integer quadrupolar nuclei in nuclear magnetic resonance of solids: Second-order quadrupolar and resonance offset effects. J Chem Phys 2009; 131:194509. [DOI: 10.1063/1.3263904] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Trebosc J, Hu B, Amoureux JP, Gan Z. Through-space R3-HETCOR experiments between spin-1/2 and half-integer quadrupolar nuclei in solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 186:220-7. [PMID: 17379553 DOI: 10.1016/j.jmr.2007.02.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 02/25/2007] [Indexed: 05/14/2023]
Abstract
We present several new methods that allow to obtain through-space 2D HETCOR spectra between spin-1/2 and half-integer quadrupolar nuclei in the solid state. These methods use the rotary-resonance concept to create hetero-nuclear coherences through the dipolar interaction instead of scalar coupling into the HMQC and refocused INEPT experiments for spin n/2 (n>1). In opposite to those based on the cross-polarization transfer to quadrupolar nuclei, the methods are very robust and easy to set-up.
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Affiliation(s)
- J Trebosc
- UCCS, CNRS-8181, Université de Lille, FR-59652 Villeneuve d'Ascq, France
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17
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Ashbrook SE, Wimperis S. Spin-locking of half-integer quadrupolar nuclei in nuclear magnetic resonance of solids: creation and evolution of coherences. J Chem Phys 2006; 120:2719-31. [PMID: 15268416 DOI: 10.1063/1.1638995] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Spin-locking of half-integer quadrupolar nuclei, such as 23Na (I=3/2) and 27Al (I=5/2), is of renewed interest owing to the development of variants of the multiple-quantum and satellite-transition magic angle spinning (MAS) nuclear magnetic resonance experiments that either utilize spin-locking directly or offer the possibility that spin-locked states may arise. However, the large magnitude and, under MAS, the time dependence of the quadrupolar interaction often result in complex spin-locking phenomena that are not widely understood. Here we show that, following the application of a spin-locking pulse, a variety of coherence transfer processes occur on a time scale of approximately 1/omegaQ before the spin system settles down into a spin-locked state which may itself be time dependent if MAS is performed. We show theoretically for both spin I=3/2 and 5/2 nuclei that the spin-locked state created by this initial rapid dephasing typically consists of a variety of single- and multiple-quantum coherences and nonequilibrium population states and we discuss the subsequent evolution of these under MAS. In contrast to previous work, we consider spin-locking using a wide range of radio frequency field strengths, i.e., a range that covers both the "strong-field" (omega1 >> omegaQPAS and "weak-field" (omega1 << omegaQPAS limits. Single- and multiple-quantum filtered spin-locking experiments on NaNO2, NaNO3, and Al(acac)3, under both static and MAS conditions, are used to illustrate and confirm the results of the theoretical discussion.
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Affiliation(s)
- Sharon E Ashbrook
- Department of Chemistry, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
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18
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Vosegaard T, Kehlet C, Khaneja N, Glaser SJ, Nielsen NC. Improved Excitation Schemes for Multiple-Quantum Magic-Angle Spinning for Quadrupolar Nuclei Designed Using Optimal Control Theory. J Am Chem Soc 2005; 127:13768-9. [PMID: 16201779 DOI: 10.1021/ja054035g] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated the use of optimal control theory for the design of improved multiple-quantum excitation schemes for the popular multiple-quantum magic-angle spinning NMR experiment for quadrupolar nuclei with half-integer quadrupolar spin. The advantage of the new low-power experiments, termed OCFASTER, is demonstrated by sensitivity improvements approaching 50% for 87Rb in RbClO4 and RbNO3 as compared to FASTER and standard strong-pulse excitation schemes.
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Affiliation(s)
- Thomas Vosegaard
- Center for Insoluble Protein Structures (inSPIN), University of Aarhus, DK-8000 Aarhus C, Denmark.
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19
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Gu J, Power WP. Improved quantitation in 3QMAS of spin 5/2 nuclei by RF power modulation of FAM-II. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2005; 27:192-199. [PMID: 15681136 DOI: 10.1016/j.ssnmr.2004.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2003] [Revised: 10/25/2004] [Indexed: 05/24/2023]
Abstract
High-resolution NMR of quadrupolar I = 5/2 nuclei using triple-quantum magic angle spinning (3QMAS) techniques can provide more accurate quantitative information on sites with small quadrupolar coupling constants by changing the pulse strength in addition to the pulse length in the FAM-II multiple-quantum conversion sequence. These effects are illustrated using (27)Al NMR of yttrium aluminium garnet and andalusite.
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Affiliation(s)
- Jun Gu
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ont., Canada N2L 3G1
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20
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Amoureux JP, Delevoye L, Steuernagel S, Gan Z, Ganapathy S, Montagne L. Increasing the sensitivity of 2D high-resolution NMR methods applied to quadrupolar nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2005; 172:268-278. [PMID: 15649754 DOI: 10.1016/j.jmr.2004.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Revised: 10/31/2004] [Indexed: 05/24/2023]
Abstract
Gan and Kwak recently proposed a soft-pulse added mixing (SPAM) idea in the classical two-pulse multiple-quantum magic-angle spinning scheme. In the SPAM method, a soft pi/2 pulse is added after the second hard-pulse (conversion pulse) and all coherence orders in between them are constructively used to obtain the signal. We, here, further extend this idea to distributed samples where the signal mainly results from echo pathways and that from anti-echo pathways dies out after a few t1 increments. We show that, with a combination of SPAM and collection of fewer anti-echoes, an enhancement of the signal to noise ratio by a factor of ca. 3 may be obtained over the z-filtered version. This may prove to be useful even for samples with long T2' relaxation times.
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Affiliation(s)
- J P Amoureux
- LCPS, CNRS-8012, ENSCL-USTL, 59652 Villeneuve d'Ascq, France.
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21
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Mali G, Kaucic V. Enhancing sensitivity or resolution of homonuclear correlation experiment for half-integer quadrupolar nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 171:48-56. [PMID: 15504681 DOI: 10.1016/j.jmr.2004.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Indexed: 05/24/2023]
Abstract
We have recently introduced double-quantum homonuclear correlation NMR experiment for half-integer quadrupolar nuclei in solids, which was based on rotary resonance recoupling [J. Chem. Phys. 120 (2004) 2835]. In this contribution we show on two 23Na (I=3/2) containing samples, Na2SO4 and Na2HPO4, that the efficiency of the experiment can be substantially enhanced by adding rotor assisted population transfer (RAPT) and Carr-Purcell-Meiboom-Gill (CPMG) sequences to it. We also present an upgraded two-dimensional experiment, in which double- and six-quantum coherences are correlated during t1 evolution period, yielding a high-resolution isotropic spectrum along an indirectly detected dimension. The sensitivity of the upgraded experiment is, however, greatly reduced compared to the sensitivity of the original experiment, so that its application is feasible only when RAPT and CPMG can be used as well.
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Affiliation(s)
- Gregor Mali
- National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia.
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22
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Goldbourt A, Vinogradov E, Goobes G, Vega S. High resolution heteronuclear correlation NMR spectroscopy between quadrupolar nuclei and protons in the solid state. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 169:342-350. [PMID: 15261632 DOI: 10.1016/j.jmr.2004.05.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Revised: 05/07/2004] [Indexed: 05/24/2023]
Abstract
A high resolution two-dimensional solid state NMR experiment is presented that correlates half-integer quadrupolar spins with protons. In this experiment the quadrupolar nuclei evolve during t1 under a split-t1, FAM-enhanced MQMAS pulse scheme. After each t1 period ending at the MQMAS echo position, single quantum magnetization is transferred, via a cross polarization process in the mixing time, from the quadrupolar nuclei to the protons. High-resolution proton signals are then detected in the t2 time domain during wPMLG5* homonuclear decoupling. The experiment has been demonstrated on a powder sample of sodium citrate and 23Na-1H 2D correlation spectra have been obtained. From the HETCOR spectra and the regular MQMAS spectrum, the three crystallographically inequivalent Na+ sites in the asymmetric unit were assigned. This MQMAS-wPMLG HETCOR pulse sequence can be used for spectral editing of half-integer quadrupolar nuclei coupled to protons.
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Affiliation(s)
- A Goldbourt
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
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23
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Larsen FH, Farnan I. Site Populations and Short Range Order in Aluminosilicates Investigated by 27Al Solid-State NMR. J Phys Chem B 2004. [DOI: 10.1021/jp049603d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Flemming H. Larsen
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | - Ian Farnan
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
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24
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Gan Z, Kwak HT. Enhancing MQMAS sensitivity using signals from multiple coherence transfer pathways. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 168:346-351. [PMID: 15140446 DOI: 10.1016/j.jmr.2004.03.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2004] [Revised: 03/20/2004] [Indexed: 05/24/2023]
Abstract
Multiple-quantum magic-angle spinning experiment removes second-order quadrupolar broadening from the central-transition of half-integer quadrupolar nuclei. This paper presents a novel scheme to enhance the sensitivity of MQMAS using signals from multiple coherence transfer pathways. The enhancement can be obtained in two ways. The first method uses the multiplex phase cycling to acquire MQMAS spectra from various coherence transfer pathways simultaneously. An addition of spectra collected with no extra time enhances the efficiency of the experiment. The second method, soft-pulse-added-mixing, is designed based on a complete alias of coherence transfer pathways. By properly fixing the soft-pulse phase, signals from various coherence transfer pathways can add constructively resulting higher signal intensities. The two methods are demonstrated for sensitivity enhancement with samples of spin-3/2 and 5/2.
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Affiliation(s)
- Zhehong Gan
- National High Magnetic Field Laboratory, Center of Interdisciplinary Magnetic Resonance, Tallahassee, FL 32310, USA.
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25
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Liu Z, Deng F, Ding S. Effects of pulse strength, width, and sample spinning speed on the spectral spin diffusion of multiquantum coherences of spin-32 quadrupolar nuclei. J Chem Phys 2004; 120:740-8. [PMID: 15267909 DOI: 10.1063/1.1630569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The effects of radio-frequency pulse strength, width, and sample spinning speed on the spin-diffusion spectrum of half-integer quadrupolar spins in solids have been studied by theoretical, numerical, and experimental investigations. It is revealed that the line shape of the cross peaks changes nonmonotonically with respect to the change of pulse strength, pulse width, or sample spinning speed. It is also found that the sample spinning speed has much more pronounced influence on the spin diffusion spectral line shape. In many cases of practical importance, the effect of sample spinning must be included in spectral analysis, in contrast to the practice of previous studies. Moreover, this effect can be exploited to further improve the precision in the determination of relative orientation of the electric-field gradient tensors of the exchange partners.
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Affiliation(s)
- Zhihong Liu
- Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
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26
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Ashbrook SE, Wimperis S. SCAM-STMAS: satellite-transition MAS NMR of quadrupolar nuclei with self-compensation for magic-angle misset. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 162:402-416. [PMID: 12810026 DOI: 10.1016/s1090-7807(03)00016-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Several methods are available for the acquisition of high-resolution solid-state NMR spectra of quadrupolar nuclei with half-integer spin quantum number. Satellite-transition MAS (STMAS) offers an approach that employs only conventional MAS hardware and can yield substantial signal enhancements over the widely used multiple-quantum MAS (MQMAS) experiment. However, the presence of the first-order quadrupolar interaction in the satellite transitions imposes the requirement of a high degree of accuracy in the setting of the magic angle on the NMR probehead. The first-order quadrupolar interaction is only fully removed if the sample spinning angle, chi, equals cos(-1)(1/3) exactly and rotor synchronization is performed. The required level of accuracy is difficult to achieve experimentally, particularly when the quadrupolar interaction is large. If the magic angle is not set correctly, the first-order splitting is reintroduced and the spectral resolution is severely compromised. Recently, we have demonstrated a novel STMAS method (SCAM-STMAS) that is self-compensated for angle missets of up to +/-1 degrees via coherence transfer between the two different satellite transitions ST(+)(m(I)=+3/2<-->+1/2) and ST(-)(m(I)=-1/2<-->-3/2) midway through the t(1) period. In this work we describe in more detail the implementation of SCAM-STMAS and demonstrate its wider utility through 23Na (I=3/2), 87 Rb (I=3/2), 27 Al (I=5/2), and 59 Co (I=7/2) NMR. We discuss linewidths in SCAM-STMAS and the limits over which angle-misset compensation is achieved and we demonstrate that SCAM-STMAS is more tolerant of temporary spinning rate fluctuations than STMAS, resulting in less "t(1) noise" in the two-dimensional spectrum. In addition, alternative correlation experiments, for example involving the use of double-quantum coherences, that similarly display self-compensation for angle misset are investigated. The use of SCAM-STMAS is also considered in systems where other high-order interactions, such as third-order quadrupolar effects or second-order quadrupole-CSA cross-terms, are present. Finally, we show that the sensitivity of the experiment can be improved through the use of amplitude-modulated pulses.
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Affiliation(s)
- Sharon E Ashbrook
- School of Chemistry, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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27
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Amoureux JP, Morais C, Trebosc J, Rocha J, Fernandez C. I-STMAS, a new high-resolution solid-state NMR method for half-integer quadrupolar nuclei. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2003; 23:213-223. [PMID: 12787904 DOI: 10.1016/s0926-2040(03)00011-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In complement to the previously proposed multiple-quantum magic-angle-spinning (MQMAS) and satellite transition MAS (STMAS) sequences, we describe a new two-dimensional high-resolution method, inverse-STMAS (I-STMAS) that allows second-order quadrupolar averaging. Like STMAS, I-STMAS correlates second-order quadrupole dephasing occurring on coherences related to the central transition (CT) and satellite transitions (STs), but does it in a reverse manner: CT evolves during the t(1) period while STs are detected during t(2). Although STMAS and I-STMAS are symmetric, there are some interesting and useful differences between the two methods. For example, we show that during the acquisition time t(2), it is possible to over-sample the data and then to process them to suppress the CT-CT correlation resonance.
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Affiliation(s)
- Jean-Paul Amoureux
- LCPS, CNRS-8012, Université de Lille-1, 59655 Villeneuve d'Ascq, France.
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28
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Rovnyak D, Filip C, Itin B, Stern AS, Wagner G, Griffin RG, Hoch JC. Multiple-quantum magic-angle spinning spectroscopy using nonlinear sampling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 161:43-55. [PMID: 12660110 DOI: 10.1016/s1090-7807(02)00189-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
NMR spectroscopy is a relatively insensitive technique and many biomolecular applications operate near the limits of sensitivity and resolution. A particularly challenging example is detection of the quadrupolar nucleus 17O, due to its low natural abundance, large quadrupole couplings, and low gyromagnetic ratio. Yet the chemical shift of 17O spans almost 1000 ppm in organic molecules and it serves as a potentially unique reporter of hydrogen bonding in peptides, nucleic acids, and water, and as a valuable complement to 13C and 15N NMR. Recent developments including the multiple-quantum magic-angle spinning (MQMAS) experiment have enabled the detection of 17O in biological solids, but very long data acquisitions are required to achieve sufficient sensitivity and resolution. Here, we perform nonlinear sampling in the indirect dimension of MQMAS experiments to substantially reduce the total acquisition time and improve sensitivity and resolution. Nonlinear sampling prevents the use of the discrete Fourier transform; instead, we employ maximum entropy (MaxEnt) reconstruction. Nonlinearly sampled MQMAS spectra are shown to provide high resolution and sensitivity in several systems, including lithium sulfate monohydrate (LiSO(4)-H(2)17O) and L-asparagine monohydrate (H(2)17O). The combination of nonlinear sampling and MaxEnt reconstruction promises to make the application of 17O MQMAS practical in a wider range of biological systems.
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Affiliation(s)
- David Rovnyak
- MIT/Harvard Center for Magnetic Resonance, Massachusetts Institute of Technology, 150 Albany Street, Cambridge, MA 02139, USA
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29
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30
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Goldbourt A, Landau MV, Vega S. Characterization of Aluminum Species in Alumina Multilayer Grafted MCM-41 Using 27Al FAM(II)-MQMAS NMR. J Phys Chem B 2002. [DOI: 10.1021/jp0217132] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amir Goldbourt
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel, and Department of Chemical Engineering, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | - Miron V. Landau
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel, and Department of Chemical Engineering, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | - Shimon Vega
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel, and Department of Chemical Engineering, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
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31
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Wi S, Logan JW, Sakellariou D, Walls JD, Pines A. Rotary resonance recoupling for half-integer quadrupolar nuclei in solid-state nuclear magnetic resonance spectroscopy. J Chem Phys 2002. [DOI: 10.1063/1.1506907] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Wi S, Heise H, Pines A. Reintroducing anisotropic interactions in magic-angle-spinning NMR of half-integer quadrupolar nuclei: 3D MQMAS. J Am Chem Soc 2002; 124:10652-3. [PMID: 12207509 DOI: 10.1021/ja027043v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Selective reintroduction of anisotropic interactions such as the chemical shift anisotropy (CSA) and homonucler dipolar (HMD) coupling were implemented in a high-resolution NMR spectroscopy for half-integer quadrupolar nuclei. Rotary resonance recoupling (R(3)) combined with the multiple-quantum magic-angle spinning (MQMAS) in a three-dimensional (3D) experiment provides not only site-specific high-resolution spectra to yield the quadrupolar interaction parameters but also the CSA or HMD interaction parameters. This 3D experiment provides an avenue for the complete local structural information of half-integer quadrupolar nuclei. Three-dimensional MQMAS experiments incorporating R(3) of HMD and CSA interactions were demonstrated on model compounds containing (11)B, (23)Na, and (87)Rb nuclei.
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Affiliation(s)
- Sungsool Wi
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA
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33
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Logan JW, Urban JT, Walls JD, Lim KH, Jerschow A, Pines A. Investigations of low-amplitude radio frequency pulses at and away from rotary resonance conditions for I = 5/2 nuclei. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2002; 22:97-109. [PMID: 12469806 DOI: 10.1006/snmr.2002.0084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Additional experimental evidence of rotary resonance effects for multiple-quantum coherence conversion in a spin-5/2 system is presented. Two-dimensional plots of the relative efficiency of MQ excitation and conversion are given as a function of radio frequency (rf) amplitude and pulse width. Data are presented for the excitation of five-quantum coherence (5QC), as well as for 5QC to three-quantum coherence (3QC) conversion, 5QC to IQC (the central transition coherence) conversion, and 3QC to IQC conversion. A two-fold increase in the signal-to-noise ratio is achieved by substituting low amplitude rf pulses in place of hard rf pulses for 5QC excitation and 5QC to 3QC conversion in a mixed multiple-quantum magic angle spinning (MAS) (MMQMAS) experiment. The anisotropic line shape for the low-amplitude rf pulse version of the MMQMAS experiment was observed to be distorted from the MAS line shape. The cause and implications of the distortion are discussed.
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Affiliation(s)
- John W Logan
- Materials Sciences Division, 1 Cyclotron Rd, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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34
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Walls JD, Lim KH, Logan JW, Urban JT, Jerschow A, Pines A. Theoretical investigations of I=5/2 quadrupolar spin dynamics in the sudden-passage regime. J Chem Phys 2002. [DOI: 10.1063/1.1483256] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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35
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Prasad S, Kwak HT, Clark T, Grandinetti PJ. A simple technique for determining nuclear quadrupole coupling constants with RAPT solid-state NMR spectroscopy. J Am Chem Soc 2002; 124:4964-5. [PMID: 11982353 DOI: 10.1021/ja025910q] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An enhanced Rotor Assisted Population Transfer (RAPT) experiment is presented and used as a simple and fast technique to measure the magnitude of the nuclear quadrupolar coupling constant of half-integer quadrupolar nuclei. The enhanced RAPT sequence consists of a train of Gaussian pulses with alternating off-resonant frequencies of +/-nuoff. Simulated and experimental results demonstrating the method are given in the case of 87Rb (spin 3/2) and 27Al (spin 5/2) nuclei. The RAPT sequence is also used to selectively suppress resonances based on their quadrupolar coupling constant.
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Affiliation(s)
- Subramanian Prasad
- Department of Chemistry, Ohio State University, 120 West 18th Avenue, Columbus, Ohio 43210, USA
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36
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d'Espinose de la Caillerie JB, Man PP, Vicente MA, Lambert JF. 27Al MQ-MAS NMR as a Tool for Structure Determination in Nanocomposite Materials: The Nature of Al Pillars in “Al13−heidi” Pillared Clays. J Phys Chem B 2002. [DOI: 10.1021/jp014024j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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37
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Lefort R, Wiench JW, Pruski M, Amoureux JP. Optimization of data acquisition and processing in Carr–Purcell–Meiboom–Gill multiple quantum magic angle spinning nuclear magnetic resonance. J Chem Phys 2002. [DOI: 10.1063/1.1433000] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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38
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Goldbourt A, Vega S. Signal enhancement in 5QMAS spectra of spin-5/2 quadrupolar nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 154:280-286. [PMID: 11846585 DOI: 10.1006/jmre.2001.2475] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
5QMAS experiments on spin-5/2 systems display a low sensitivity compared with their 3QMAS counterparts. Nevertheless, the superior resolution of 5QMAS over 3QMAS makes these experiments a favorable choice for many materials. We report an enhancement scheme for the 5QMAS experiment, using an improved five-quantum excitation pulse scheme combined with a FAM-II conversion pulse. The results are verified experimentally on a polycrystalline sample of gamma-(27)Al(2)O(3), showing an enhancement factor of 2.4 over the simple two-pulse (CW) 5QMAS scheme. Numerical computations of the efficiency parameter epsilon support these results.
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39
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Lim KH, Charpentier T, Pines A. Efficient triple-quantum excitation in modified RIACT MQMAS NMR for I=3/2 nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 154:196-204. [PMID: 11846577 DOI: 10.1006/jmre.2001.2471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new approach involving the creation of triple-quantum (TQ) coherences from both TQ and central transitions (CT) is investigated, in order to enhance the efficiency of triple-quantum excitation for I=3/2 nuclei. The RIACT excitation scheme, a soft pi/2 and hard spin-locking pulse, is shown to induce both adiabatic coherence transfer between CT and TQ coherences and TQ nutation. By combining the RIACT scheme with the presaturation of the satellite transitions, a significant improvement in the TQ excitation can be achieved mainly through enhanced CT polarization via the RIACT mechanism, in particular for nuclei with moderate to large quadrupole coupling constants (> or = 2.0 MHz). There also exists a nontrivial contribution from the TQ transition, which depends on the size of the quadrupole interaction.
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Affiliation(s)
- Kwang Hun Lim
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, USA
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40
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Walls JD, Lim KH, Pines A. Theoretical studies of the spin dynamics of quadrupolar nuclei at rotational resonance conditions. J Chem Phys 2002. [DOI: 10.1063/1.1421613] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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42
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Lupulescu A, Brown SP, Spiess HW. Rotor-encoded heteronuclear MQ MAS NMR spectroscopy of half-integer quadrupolar and spin I=1/2 nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 154:101-129. [PMID: 11820831 DOI: 10.1006/jmre.2001.2464] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new two-dimensional heteronuclear multiple-quantum magic-angle spinning (MQ MAS) experiment is presented which combines high resolution for the half-integer quadrupolar nucleus with information about the dipolar coupling between the quadrupolar nucleus and a spin I=1/2 nucleus. Homonuclear MQ coherence is initially created for the half-integer quadrupolar nucleus by a single pulse as in a standard MQ MAS experiment. REDOR recoupling of the heteronuclear dipolar coupling then allows the creation of a heteronuclear multiple-quantum coherence comprising multiple- and single-quantum coherence of the quadrupolar and spin I=1/2 nucleus, respectively, which evolves during t1. Provided that the t1 increment is not rotor synchronized, rotor-encoded spinning-sideband patterns are observed in the indirect dimension. Simulated spectra for an isolated IS spin pair show that these patterns depend on the recoupling time, the magnitude of the dipolar coupling, the quadrupolar parameters, as well as the relative orientation of the quadrupolar and dipolar principal axes systems. Spectra are presented for Na2HPO4, with the heteronuclear 23Na-1HMQ MAS experiments beginning with the excitation of 23Na (spin I=3/2) three-quantum coherence. Coherence counting experiments demonstrate that four- and two-quantum coherences evolve during t1. The heteronuclear spinning-sideband patterns observed for the three-spin H-Na-H system associated with the Na(2) site are analyzed. For an IS2 system, simulated spectra show that, considering the free parameters, the spinning-sideband patterns are particularly sensitive to only, first, the angle between the two IS internuclear vectors and, second, the two heteronuclear dipolar couplings. It is demonstrated that the proton localization around the Na(2) site according to the literature crystal structure of Na2HPO4 is erroneous. Instead, the experimental data is consistent with two alternative different structural arrangements, whereby either there is a deviation of 10 degrees from linearity for the case of two identical Na-H distances, or there is a linear arrangement, but the two Na-H distances are different. Furthermore, the question of the origin of spinning-sidebands in the (homonuclear) MQ MAS experiment is revisited. It is shown that the asymmetric experimental MQ sideband pattern observed for the low-C(Q) Na(2) site in Na(2)HPO4 can only be explained by considering the 23Na chemical shift anisotropy.
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Affiliation(s)
- Adonis Lupulescu
- Max-Planck-Institut für Polymerforschung, D-55021 Mainz, Germany
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Clark TM, Grandinetti PJ, Florian P, Stebbins JF. An 17O NMR Investigation of Crystalline Sodium Metasilicate: Implications for the Determination of Local Structure in Alkali Silicates. J Phys Chem B 2001. [DOI: 10.1021/jp011289p] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- T. M. Clark
- Department of Chemistry, The Ohio State University, 120 West 18th Avenue, Columbus, Ohio 43210-1173
| | - P. J. Grandinetti
- Department of Chemistry, The Ohio State University, 120 West 18th Avenue, Columbus, Ohio 43210-1173
| | - P. Florian
- CNRS-CRMHT, 1D Av. de la Recherche Scientifique, 45071 Orléans Cedex 2, France
| | - J. F. Stebbins
- Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305
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Wu G, Dong S. Two-dimensional (17)O multiple quantum magic-angle spinning NMR of organic solids. J Am Chem Soc 2001; 123:9119-25. [PMID: 11552820 DOI: 10.1021/ja0102181] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report two-dimensional (2D) (17)O multiple-quantum magic-angle spinning (MQMAS) NMR spectra for four (17)O-labeled organic compounds: [(17)O(2)]-D-alanine (1), potassium hydrogen [(17)O(4)]dibenzoate (2), [(17)O(4)]-D,L-glutamic acid.HCl (3) and [2,4-(17)O(2)]uracil (4). The high spectral resolution observed in the 2D (17)O MQMAS NMR spectra allows extraction of precise (17)O NMR parameters for all crystallographically distinct oxygen sites. We demonstrate that rotor synchronization is important in obtaining high-quality (17)O MQMAS spectra for organic compounds. Several issues related to the potential of (17)O MQMAS NMR for large biomolecular systems are also discussed.
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Affiliation(s)
- G Wu
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6.
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Kwak HT, Prasad S, Yao Z, Grandinetti PJ, Sachleben JR, Emsley L. Enhanced sensitivity in RIACT/MQ-MAS NMR experiments using rotor assisted population transfer. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2001; 150:71-80. [PMID: 11330985 DOI: 10.1006/jmre.2001.2313] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The rotor assisted population transfer (RAPT) sequence is used to enhance the sensitivity of the RIACT(II) experiment for spin-3/2 quadrupolar nuclei. A detailed theoretical analysis of the polarizations that contribute to different types of MQ-MAS experiments is provided. In particular, two polarization pathways are distinguished for the creation of triple-quantum coherence. The existence of these pathways is experimentally demonstrated by comparing the sensitivities of different sequences with and without RAPT preparation.
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Affiliation(s)
- H T Kwak
- Department of Chemistry, Ohio State University, Columbus, Ohio 43210-1173, USA
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