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Crafton MJ, Huang TY, Yue Y, Giovine R, Wu VC, Dun C, Urban JJ, Clément RJ, Tong W, McCloskey BD. Tuning Bulk Redox and Altering Interfacial Reactivity in Highly Fluorinated Cation-Disordered Rocksalt Cathodes. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18747-18762. [PMID: 37014990 DOI: 10.1021/acsami.2c16974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Lithium-excess, cation-disordered rocksalt (DRX) materials have been subject to intense scrutiny and development in recent years as potential cathode materials for Li-ion batteries. Despite their compositional flexibility and high initial capacity, they suffer from poorly understood parasitic degradation reactions at the cathode-electrolyte interface. These interfacial degradation reactions deteriorate both the DRX material and electrolyte, ultimately leading to capacity fade and voltage hysteresis during cycling. In this work, differential electrochemical mass spectrometry (DEMS) and titration mass spectrometry are combined to quantify the extent of bulk redox and surface degradation reactions for a set of Mn2+/4+-based DRX oxyfluorides during initial cycling with a high-voltage charging cutoff (4.8 V vs Li/Li+). Increasing the fluorine content from 7.5 to 33.75% is shown to diminish oxygen redox and suppresses high-voltage O2 evolution from the DRX surface. Additionally, electrolyte degradation processes resulting in the formation of both gaseous species and electrolyte-soluble protic species are observed. Subsequently, DEMS is paired with a fluoride-scavenging additive to demonstrate that increasing fluorine content leads to increased dissolution of fluorine from the DRX material into the electrolyte. Finally, a suite of ex situ spectroscopy techniques (X-ray photoelectron spectroscopy, inductively coupled plasma optical emission spectroscopy, and solid-state nuclear magnetic resonance spectroscopy) are employed to study the change in DRX composition during charging, revealing the dissolution of manganese and fluorine from the DRX material at high voltages. This work provides insight into the degradation processes occurring at the DRX-electrolyte interface and points toward potential routes of interfacial stabilization.
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Affiliation(s)
- Matthew J Crafton
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
- Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Tzu-Yang Huang
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
- Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Yuan Yue
- Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Raynald Giovine
- Materials Department, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Vincent C Wu
- Materials Department, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Chaochao Dun
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jeffrey J Urban
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Raphaële J Clément
- Materials Department, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Wei Tong
- Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Bryan D McCloskey
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
- Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Satish R, Wichmann L, Crafton MJ, Giovine R, Li L, Ahn J, Yue Y, Tong W, Chen G, Wang C, Clement RJ, Kostecki R. Exposure History and its Effect Towards Stabilizing Li Exchange Across Disordered Rock Salt Interfaces. ChemElectroChem 2021. [DOI: 10.1002/celc.202100891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Rohit Satish
- Energy Storage and Distributed Resources Division Lawrence Berkeley National Laboratory Berkeley USA CA, 94720
| | - Lennart Wichmann
- MEET Battery Research Center University of Münster Corrensstraße 46 D-48149 Münster Germany
| | - Matthew J. Crafton
- Energy Storage and Distributed Resources Division Lawrence Berkeley National Laboratory Berkeley USA CA, 94720
- Department of Chemical and Biomolecular Engineering University of California Berkeley CA 94720 USA
| | - Raynald Giovine
- Materials Department University of California Santa Barbara Santa Barbara USA CA, 93106
| | - Linze Li
- Environmental Molecular Sciences Laboratory Pacific Northwest National Laboratory 902 Battelle Boulevard Richland Washington 99354 United States
| | - Juhyeon Ahn
- Energy Storage and Distributed Resources Division Lawrence Berkeley National Laboratory Berkeley USA CA, 94720
| | - Yuan Yue
- Energy Storage and Distributed Resources Division Lawrence Berkeley National Laboratory Berkeley USA CA, 94720
| | - Wei Tong
- Energy Storage and Distributed Resources Division Lawrence Berkeley National Laboratory Berkeley USA CA, 94720
| | - Guoying Chen
- Energy Storage and Distributed Resources Division Lawrence Berkeley National Laboratory Berkeley USA CA, 94720
| | - Chongmin Wang
- Environmental Molecular Sciences Laboratory Pacific Northwest National Laboratory 902 Battelle Boulevard Richland Washington 99354 United States
| | - Raphäele J. Clement
- Materials Department University of California Santa Barbara Santa Barbara USA CA, 93106
| | - Robert Kostecki
- Energy Storage and Distributed Resources Division Lawrence Berkeley National Laboratory Berkeley USA CA, 94720
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Matsunaga T, Takegoshi K. Magic-angle turning with double acquisition. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 274:1-6. [PMID: 27835747 DOI: 10.1016/j.jmr.2016.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 10/28/2016] [Accepted: 10/31/2016] [Indexed: 05/06/2023]
Abstract
The double-acquisition scheme for efficient data collection of hypercomplex data (the States method) of a two-dimensional experiment is adopted to magic-angle hopping (MAH) and magic-angle turning (MAT) experiments, which are powerful methods to measure the principal values of the chemical shift anisotropy (CSA) in a powder sample. It is shown that the double acquisition MAT (DAMAT) sequence realizes the S/N ratio comparable to or better than those of other variants of the MAH/MAT sequences. In addition, we show that DAMAT has preferable features that there are no spinning sidebands in the indirect dimension, and no spectral shearing is necessary.
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Affiliation(s)
- Tatsuya Matsunaga
- Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan
| | - K Takegoshi
- Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan.
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Martin RW, Kelly JE, Collier KA. Spatial reorientation experiments for NMR of solids and partially oriented liquids. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 90-91:92-122. [PMID: 26592947 PMCID: PMC6936739 DOI: 10.1016/j.pnmrs.2015.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 06/05/2023]
Abstract
Motional reorientation experiments are extensions of Magic Angle Spinning (MAS) where the rotor axis is changed in order to average out, reintroduce, or scale anisotropic interactions (e.g. dipolar couplings, quadrupolar interactions or chemical shift anisotropies). This review focuses on Variable Angle Spinning (VAS), Switched Angle Spinning (SAS), and Dynamic Angle Spinning (DAS), all of which involve spinning at two or more different angles sequentially, either in successive experiments or during a multidimensional experiment. In all of these experiments, anisotropic terms in the Hamiltonian are scaled by changing the orientation of the spinning sample relative to the static magnetic field. These experiments vary in experimental complexity and instrumentation requirements. In VAS, many one-dimensional spectra are collected as a function of spinning angle. In SAS, dipolar couplings and/or chemical shift anisotropies are reintroduced by switching the sample between two different angles, often 0° or 90° and the magic angle, yielding a two-dimensional isotropic-anisotropic correlation spectrum. Dynamic Angle Spinning (DAS) is a related experiment that is used to simultaneously average out the first- and second-order quadrupolar interactions, which cannot be accomplished by spinning at any unique rotor angle in physical space. Although motional reorientation experiments generally require specialized instrumentation and data analysis schemes, some are accessible with only minor modification of standard MAS probes. In this review, the mechanics of each type of experiment are described, with representative examples. Current and historical probe and coil designs are discussed from the standpoint of how each one accomplishes the particular objectives of the experiment(s) it was designed to perform. Finally, applications to inorganic materials and liquid crystals, which present very different experimental challenges, are discussed. The review concludes with perspectives on how motional reorientation experiments can be applied to current problems in chemistry, molecular biology, and materials science, given the many advances in high-field NMR magnets, fast spinning, and sample preparation realized in recent years.
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Affiliation(s)
- Rachel W Martin
- Department of Chemistry, University of California, Irvine 92697-2025, United States; Department of Molecular Biology and Biochemistry, University of California, Irvine 92697-3900, United States.
| | - John E Kelly
- Department of Chemistry, University of California, Irvine 92697-2025, United States
| | - Kelsey A Collier
- Department of Physics and Astronomy, University of California, Irvine 92697-4575, United States
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Hung I, Gan Z. An efficient amplification pulse sequence for measuring chemical shift anisotropy under fast magic-angle spinning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 213:196-199. [PMID: 21962909 DOI: 10.1016/j.jmr.2011.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 08/25/2011] [Accepted: 09/06/2011] [Indexed: 05/31/2023]
Abstract
A two-dimensional experiment for measuring chemical shift anisotropy (CSA) under fast magic-angle spinning (MAS) is presented. The chemical shift anisotropy evolution is amplified by a sequence of π-pulses that repetitively interrupt MAS averaging. The amplification generates spinning sideband manifolds in the indirect dimension separated by the isotropic shift along the direct dimension. The basic unit of the pulse sequence is designed based on the magic-angle turning experiment and can be concatenated for larger amplification factors.
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Affiliation(s)
- Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
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Hu YY, Schmidt-Rohr K. Technical aspects of fast magic-angle turning NMR for dilute spin-1/2 nuclei with broad spectra. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2011; 40:51-59. [PMID: 21782396 DOI: 10.1016/j.ssnmr.2011.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 04/26/2011] [Accepted: 04/27/2011] [Indexed: 05/31/2023]
Abstract
For obtaining sideband-free spectra of high-Z spin-1/2 nuclei with large (>1000 ppm) chemical-shift anisotropies and broad isotropic-shift dispersion, we recently identified Gan's modified five-pulse magic-angle turning (MAT) experiment as the best available broadband pulse sequence, and adapted it to fast magic-angle spinning. Here, we discuss technical aspects such as pulse timings that compensate for off-resonance effects and are suitable for large CSAs over a range of 1.8γB(1); methods to minimize the duration of z-periods by cyclic decrementation; shearing without digitization artifacts, by sharing between channels (points); and maximizing the sensitivity by echo-matched full-Gaussian filtering. The method is demonstrated on a model sample of mixed amino acids and its large bandwidth is highlighted by comparison with the multiple-π-pulse PASS technique. Applications to various tellurides are shown; these include GeTe, Sb(2)Te(3) and Ag(0.53)Pb(18)Sb(1.2)Te(20), with spectra spanning up to 190 kHz, at 22 kHz MAS. We have also determined the (125)Te chemical shift anisotropies from the intensities of the spinning sidebands resolved by isotropic-shift separation.
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Affiliation(s)
- Y-Y Hu
- Ames Laboratory and Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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Hung I, Gan Z. On the magic-angle turning and phase-adjusted spinning sidebands experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 204:150-154. [PMID: 20202873 DOI: 10.1016/j.jmr.2010.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/25/2010] [Accepted: 02/08/2010] [Indexed: 05/28/2023]
Abstract
The underlying relation between the magic-angle turning (MAT) and phase-adjusted spinning sidebands (PASS) experiments is examined. The MAT experiment satisfies the PASS conditions for separating spinning sidebands with a non-constant total evolution time and only requires linear t(1) increments of up to one rotor period. The time-domain data of the two experiments are related by a shearing transformation. A combination of the linear evolution-time increments of MAT and simple data processing of PASS are particularly attractive for the implementation of MAT for measuring chemical shift anisotropy.
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Affiliation(s)
- Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
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Hu YY, Levin EM, Schmidt-Rohr K. Broadband “Infinite-Speed” Magic-Angle Spinning NMR Spectroscopy. J Am Chem Soc 2009; 131:8390-1. [PMID: 19489580 DOI: 10.1021/ja903334p] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan-Yan Hu
- Ames Laboratory and Department of Chemistry, Iowa State University, Ames, Iowa 50011, and Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011
| | - E. M. Levin
- Ames Laboratory and Department of Chemistry, Iowa State University, Ames, Iowa 50011, and Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011
| | - Klaus Schmidt-Rohr
- Ames Laboratory and Department of Chemistry, Iowa State University, Ames, Iowa 50011, and Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011
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Hu JZ, Sears JA, Kwak JH, Hoyt DW, Wang Y, Peden CHF. An isotropic chemical shift-chemical shift anisotropic correlation experiment using discrete magic angle turning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 198:105-110. [PMID: 19246221 DOI: 10.1016/j.jmr.2009.01.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 01/15/2009] [Accepted: 01/22/2009] [Indexed: 05/27/2023]
Abstract
An isotropic-anisotropic shift 2D correlation spectroscopy is introduced that combines the advantages of both magic angle turning (MAT) and magic angle hopping (MAH) technologies. In this new approach, denoted DMAT for "discrete magic angle turning", the sample rotates clockwise followed by an anticlockwise rotation of exactly the same amount with each rotation less or equal than 360 degrees but greater than 240 degrees , with the rotation speed being constant only for times related to the evolution dimension. This back and forth rotation is repeated and synchronized with a special radio frequency (RF) pulse sequence to produce an isotropic-anisotropic shift 2D correlation spectrum. For any spin-interaction of rank-2 such as chemical shift anisotropy, isotropic magnetic susceptibility interaction, and residual homo-nuclear dipolar interaction in biological fluid samples, the projection along the isotropic dimension is a high resolution spectrum. Since a less than 360 degrees sample rotation is involved, the design potentially allows for in situ control over physical parameters such as pressure, flow conditions, feed compositions, and temperature so that true in situ NMR investigations can be carried out.
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Affiliation(s)
- Jian Zhi Hu
- Institute for Interfacial Catalysis, Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K8-98, Richland, WA 99352, USA.
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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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Hu JZ, Ye C, Pugmire RJ, Grant DM. A high-resolution (13)C 3D CSA-CSA-CSA correlation experiment by means of magic angle turning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2000; 145:230-236. [PMID: 10910691 DOI: 10.1006/jmre.2000.2084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
It is shown in this paper that a previously reported 90 degrees sample flipping (13)C 2D CSA-CSA correlation experiment may be carried out alternatively by employing constant slow sample rotation about the magic angle axis and by synchronizing the read pulse to 13 of the rotor cycle. A high-resolution 3D CSA-CSA-CSA correlation experiment based on the magic angle turning technique is reported in which the conventional 90 degrees 2D CSA-CSA powder pattern for each carbon in a system containing a number of inequivalent carbons may be separated according to the isotropic chemical shift value. The technique is demonstrated on 1,2,3-trimethoxybenzene in which all of the overlapping powder patterns that cannot be segregated by the 2D CSA-CSA experiment are resolved successfully by the 3D CSA-CSA-CSA experiment, including even the two methoxy groups (M(1) and M(3)) whose isotropic shifts, confirmed by high-speed MAS, are separated by only 1 ppm. A difference of 4 ppm in the principal value component (delta(33)) between M(1) and M(3) is readily obtained.
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Affiliation(s)
- J Z Hu
- Department of Chemistry, University of Utah, Salt Lake City 84112, USA
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Hu JZ, Wang W, Bai S, Pugmire RJ, Taylor CMV, Grant DM. Investigation of Polyethylene by Means of Magic Angle Turning and Separated-Local-Field Experiments. Macromolecules 2000. [DOI: 10.1021/ma9916842] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jian Zhi Hu
- Departments of Chemistry and Chemical and Fuels Engineering, University of Utah, Salt Lake City, Utah 84112, and Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Wei Wang
- Departments of Chemistry and Chemical and Fuels Engineering, University of Utah, Salt Lake City, Utah 84112, and Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Shi Bai
- Departments of Chemistry and Chemical and Fuels Engineering, University of Utah, Salt Lake City, Utah 84112, and Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - R. J. Pugmire
- Departments of Chemistry and Chemical and Fuels Engineering, University of Utah, Salt Lake City, Utah 84112, and Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Craig M. V. Taylor
- Departments of Chemistry and Chemical and Fuels Engineering, University of Utah, Salt Lake City, Utah 84112, and Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - D. M. Grant
- Departments of Chemistry and Chemical and Fuels Engineering, University of Utah, Salt Lake City, Utah 84112, and Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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Hughes E, Brouwer EB, Harris RK. Fluorine-19 solid-state NMR magic-angle-turning experiments using multiple-pulse homonuclear decoupling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1999; 138:256-267. [PMID: 10341129 DOI: 10.1006/jmre.1999.1740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
For compounds giving "crowded" 1-dimensional magic-angle-spinning spectra, information about the local atomic environment in the form of the chemical shift anisotropy (CSA) is sacrificed for high resolution of the less informative isotropic chemical shift. Magic-angle-turning (MAT) NMR pulse sequences preserve the CSA information by correlating it to the isotropic chemical shift in a 2-dimensional experiment. For low natural abundance nuclei such as 13C and 15N and under 1H heteronuclear dipolar decoupling conditions, the dominant NMR interaction is the chemical shift. For abundant nuclei such as 1H, 19F, and 31P, the homonuclear dipolar interaction becomes a significant contribution to the observed linewidth in both F1 and F2 dimensions. We incorporate MREV8 homonuclear multiple-pulse decoupling sequences into the MAT experiment to give a multiple-pulse MAT (MP-MAT) experiment in which the homonuclear dipolar interaction is suppressed while maintaining the chemical shift information. Extensive use of computer simulation using GAMMA has guided the pulse sequence development. In particular, we show how the MREV8 pulses can be incorporated into a quadrature-detected sequence such as MAT. The MP-MAT technique is demonstrated for a model two-site system containing a mixture of silver trifluoroacetate and calcium difluoride. The resolution in the isotropic evolution dimension is improved by faster sample spinning, shorter MREV8 cycle times in the evolution dimension, and modifications of the MAT component of the pulse sequence. Copyright 1999 Academic Press.
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Affiliation(s)
- E Hughes
- South Road Laboratories, University of Durham, Durham, DH1 3LE, United Kingdom
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McGeorge G, Alderman DW, Grant DM. Resolution enhancement in 13C and 15N magic-angle turning experiments with TPPM decoupling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1999; 137:138-143. [PMID: 10053142 DOI: 10.1006/jmre.1998.1664] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Many solid-state spectra have been shown to have problems related to the poor proton decoupling of carbon nuclei in methylene groups under conditions of slow magic-angle turning. Two-pulse phase-modulation (TPPM) decoupling during the 2D PHORMAT chemical shift separation experiment is shown to be more effective in comparison to that obtainable at much higher spin rates using conventional CW decoupling. TPPM decoupling can also alleviate similar inadequacies when observing the 15N nucleus, particularly with NH2 groups. This is demonstrated in the 15N resonances of fully labeled l-arginine hydrochloride, where a line narrowing of about a factor of two was observed at moderate rotation rates. This significant advantage was also obtained at turning frequencies as low as 500 Hz.
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Affiliation(s)
- G McGeorge
- Department of Chemistry, University of Utah, Salt Lake City, Utah, 84112-0850, USA
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ALDERMAN DW, McGEORGE GARY, HU JIANZHI, PUGMIRE RONALDJ, GRANT DAVIDM. A sensitive, high resolution magic angle turning experiment for measuring chemical shift tensor principal values. Mol Phys 1998. [DOI: 10.1080/00268979809483243] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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McGeorge G, Hu JZ, Mayne CL, Alderman DW, Pugmire RJ, Grant DM. Technique for importing greater evolution resolution in multidimensional NMR spectrum. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1997; 129:134-144. [PMID: 9441878 DOI: 10.1006/jmre.1997.1268] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A very simple and general procedure that extracts constant-evolution-frequency data from a truncated multidimensional (2D, 3D, 4D, etc.) FID is described, generalized, analyzed, and illustrated. The method replaces Fourier transformation of the evolution dimension with a linear model created from a separate, high-quality 1D FID. The equivalent of high resolution in the evolution dimension can be achieved without obtaining an extensive multidimensional FID. The analysis of the 1D FID can also be used to predict the signal to noise ratio of the extracted slices that will result from various evolution dimension sampling protocols, making it possible to develop a priori an optimal sampling strategy for the multidimensional FID. The evolution dimension need not be sampled periodically. The procedure has a potential signal-to-noise ratio advantage because it extracts usable information from a multidimensional FID at short evolution times before the magnetization has decayed significantly.
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Affiliation(s)
- G McGeorge
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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