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Gómez JS, Trébosc J, Tuan Duong N, Pourpoint F, Lafon O, Amoureux JP. Comparison of through-space homonuclear correlations between quadrupolar nuclei in solids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 348:107388. [PMID: 36841183 DOI: 10.1016/j.jmr.2023.107388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Various two-dimensional (2D) homonuclear correlation experiments have been proposed to observe proximities between identical half-integer spin quadrupolar nuclei in solids. These experiments select either the single- or double-quantum coherences during the indirect evolution period, t1. We compare here the efficiency and the robustness of the 2D double-quantum to single-quantum (DQ-SQ) and SQ-SQ homonuclear correlations for two half-integer spin quadrupolar isotopes subject to small chemical shift anisotropy (CSA): 11B with a nuclear spin I = 3/2 and 27Al with I = 5/2. Such a comparison is performed using experiments on two model samples: Li2B4O7 for 11B and AlPO4-14 for 27Al. For both isotopes, the DQ-SQ homonuclear correlations are recommended since they allow probing the proximities between nuclei with close or identical frequencies. In the case of small or moderate isotropic chemical shift differences (e.g. 11B) the [SR221] or [BR221] bracketed DQ-SQ recoupling schemes are recommended; whereas it is the BR221 un-bracketed one otherwise (e.g. 27Al).
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Affiliation(s)
- Jennifer S Gómez
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, Lille 59000, France
| | - Julien Trébosc
- Univ. Lille, CNRS, INRAE, Centrale Lille, Univ. Artois, FR 2638 - IMEC - Fédération Chevreul, Lille 59000, France
| | - Nghia Tuan Duong
- Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Frédérique Pourpoint
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, Lille 59000, France
| | - Olivier Lafon
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, Lille 59000, France.
| | - Jean-Paul Amoureux
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, Lille 59000, France; Bruker Biospin, 34 rue de l'industrie, Wissembourg 67166, France.
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2
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Yu Y, Keil P, Stevensson B, Hansen MR, Edén M. Assessment of new symmetry-based dipolar recoupling schemes for homonuclear magnetization exchange between quadrupolar nuclei in two-dimensional correlation MAS NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 316:106734. [PMID: 32590307 DOI: 10.1016/j.jmr.2020.106734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/13/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
We provide an extensive experimental and numerical evaluation of MQ-phase (S)M supercycles with M={3,4} of three groups of symmetry-based homonuclear dipolar recoupling rf-pulse sequences, [Formula: see text] , for establishing proximities among half-integer spin quadrupolar nuclei under moderately fast magic-angle-spinning (MAS) conditions in single-quantum-single-quantum (1Q-1Q) correlation NMR experiments. The relative merits of the (S)M schemes for variations in resonance offsets and rf-amplitude errors were assessed by numerically simulated magnetization transfers in spin-3/2 pairs with variable isotropic chemical shifts and quadrupolar coupling constants. Experimental demonstrations of 23Na (spin-3/2) NMR on Na2MoO4·2H2O and 27Al (spin-5/2) NMR on AlPO-CJ19 [(NH4)2Al4(PO4)4HPO4·H2O] are presented at 14.1 T and 24 kHz MAS. We recommend using the (SR221)3 or (SR221)4 supercycles for samples that exhibit small chemical-shift dispersions (<3 kHz), and any (SRNNN/2)3 scheme with N⩾10 for larger spreads of isotropic chemical shifts. However, because the (SRNNN/2)3 sequences recouple heteronuclear dipolar interactions, their application to proton-bearing samples requires high-power proton decoupling during the mixing period. Alternatively, the (SR241)3 and (SR241)4 schemes may be employed in the absence of proton decoupling, but with poorer compensation to resonance-offsets and rf-amplitude errors.
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Affiliation(s)
- Yang Yu
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Philipp Keil
- Institute for Physical Chemistry, Westfälische Wilhelms-Universität Münster, DE-48 149 Münster, Germany
| | - Baltzar Stevensson
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Michael Ryan Hansen
- Institute for Physical Chemistry, Westfälische Wilhelms-Universität Münster, DE-48 149 Münster, Germany
| | - Mattias Edén
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
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3
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Yu Y, Keil P, Hansen MR, Edén M. Improved Magnetization Transfers among Quadrupolar Nuclei in Two-Dimensional Homonuclear Correlation NMR Experiments Applied to Inorganic Network Structures. Molecules 2020; 25:molecules25020337. [PMID: 31947638 PMCID: PMC7024165 DOI: 10.3390/molecules25020337] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 11/17/2022] Open
Abstract
We demonstrate that supercycles of previously introduced two-fold symmetry dipolar recoupling schemes may be utilized successfully in homonuclear correlation nuclear magnetic resonance (NMR) spectroscopy for probing proximities among half-integer spin quadrupolar nuclei in network materials undergoing magic-angle-spinning (MAS). These (SR221)M, (SR241)M, and (SR281)M recoupling sequences with M=3 and M=4 offer comparably efficient magnetization transfers in single-quantum–single-quantum (1Q–1Q) correlation NMR experiments under moderately fast MAS conditions, as demonstrated at 14.1 T and 24 kHz MAS in the contexts of 11B NMR on a Na2O–CaO–B2O3–SiO2 glass and 27Al NMR on the open framework aluminophosphate AlPO-CJ19 [(NH4)2Al4(PO4)4HPO4·H2O]. Numerically simulated magnetization transfers in spin–3/2 pairs revealed a progressively enhanced tolerance to resonance offsets and rf-amplitude errors of the recoupling pulses along the series (SR221)M< (SR241)M< (SR281)M for increasing differences in chemical shifts between the two nuclei. Nonetheless, for scenarios of a relatively minor chemical-shift dispersions (≲3 kHz), the (SR221)M supercycles perform best both experimentally and in simulations.
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Affiliation(s)
- Yang Yu
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden;
| | - Philipp Keil
- Institute for Physical Chemistry, Westfälische Wilhelms-Universität Münster, DE-48 149 Münster, Germany; (P.K.); (M.R.H.)
| | - Michael Ryan Hansen
- Institute for Physical Chemistry, Westfälische Wilhelms-Universität Münster, DE-48 149 Münster, Germany; (P.K.); (M.R.H.)
| | - Mattias Edén
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden;
- Correspondence:
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4
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Perras FA, Bryce DL. Measuring dipolar and J coupling between quadrupolar nuclei using double-rotation NMR. J Chem Phys 2013; 138:174202. [DOI: 10.1063/1.4802192] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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5
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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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6
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Wang Q, Hu B, Lafon O, Trébosc J, Deng F, Amoureux JP. Double-quantum homonuclear NMR correlation spectroscopy of quadrupolar nuclei subjected to magic-angle spinning and high magnetic field. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 200:251-260. [PMID: 19646906 DOI: 10.1016/j.jmr.2009.07.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 07/06/2009] [Accepted: 07/08/2009] [Indexed: 05/28/2023]
Abstract
We present a new application of the R2(2)(1) symmetry-based dipolar recoupling scheme, for exciting directly double-quantum (2Q) coherences between the central transition of homonuclear half-integer quadrupolar nuclei. With respect to previously published 2Q-recoupling methods (M. Eden, D. Zhou, J. Yu, Chem. Phys. Lett. 431 (2006) 397), the R2(2)(1) sequence is used without pi/2 bracketing pulses and with an original super-cycling. This leads to an improved efficiency (a factor of two for spin-5/2) and to a much higher robustness to radio-frequency field inhomogeneity and resonance offset. The 2Q-coherence excitation performances are demonstrated experimentally by (27)Al NMR experiments on the aluminophosphates berlinite, VPI5, AlPO(4)-14, and AlPO(4)-CJ3. The two-dimensional 2Q-1Q correlation experiments incorporating these recoupling sequences allow the observation of 2Q cross-peaks between central transitions, even at high magnetic field where the difference in offset between octahedral and tetrahedral (27)Al sites exceeds 10 kHz.
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Affiliation(s)
- Q Wang
- UCCS, CNRS-8181, Lille University, Fr-59652, Villeneuve d'Ascq, France
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7
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Edén M. Homonuclear dipolar recoupling of half-integer spin quadrupolar nuclei: techniques and applications. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2009; 36:1-10. [PMID: 19595580 DOI: 10.1016/j.ssnmr.2009.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 06/16/2009] [Indexed: 05/28/2023]
Abstract
We review recent advances in solid state NMR methodology for recovering homonuclear dipolar interactions among half-integer quadrupolar spins undergoing sample rotation. Existing dipolar recoupling techniques are contrasted, based on (i) the form of their associated dipolar Hamiltonian, (ii) the different experimental conditions necessitating their realization and (iii) their roles as components in multi-dimensional NMR correlation spectroscopy. Various types of structural information accessible from such solid state NMR experimentation is reviewed. Promises and limitations of methodologies targeting homonuclear dipolar couplings between half-integer spins under high-resolution conditions are discussed, with particular focus on the demands set for structural investigations of crystalline as well as structurally disordered (amorphous) inorganic network materials.
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Affiliation(s)
- Mattias Edén
- Physical Chemistry Division, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
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8
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Edén M. Determination of absolute quadrupolar tensor orientations by double-quantum NMR on powders. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.01.061] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Brinkmann A, Kentgens APM, Anupõld T, Samoson A. Symmetry-based recoupling in double-rotation NMR spectroscopy. J Chem Phys 2009; 129:174507. [PMID: 19045358 DOI: 10.1063/1.3005395] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this contribution, we extend the theory of symmetry-based pulse sequences of types CN(n) (nu) and RN(n) (nu) in magic-angle-spinning nuclear resonance spectroscopy [M. H. Levitt, in Encyclopedia of Nuclear Magnetic Resonance, edited by D. M. Grant and R. K. Harris (Wiley, Chichester, 2002), Vol. 9]. to the case of rotating the sample simultaneously around two different angles with respect to the external magnetic field (double-rotation). We consider the case of spin-1/2 nuclei in general and the case of half-integer quadrupolar nuclei that are subjected to weak radio frequency pulses operating selectively on the central-transition polarizations. The transformation properties of the homonuclear dipolar interactions and J-couplings under central-transition-selective spin rotations are presented. We show that the pulse sequence R2(2) (1)R2(2) (-1) originally developed for homonuclear dipolar recoupling of half-integer quadrupolar nuclei under magic-angle-spinning conditions [M. Eden, D. Zhou, and J. Yu, Chem. Phys. Lett. 431, 397 (2006)] may be used for the same purpose in the case of double rotation, if the radio frequency pulses are synchronized with the outer rotation of the sample. We apply this sequence, sandwiched by central-transition selective 90 degrees pulses, to excite double-quantum coherences in homonuclear spin systems consisting of (23)Na and (27)Al nuclei.
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Affiliation(s)
- Andreas Brinkmann
- Physical Chemistry/Solid State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands.
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Mali G, Kaučič V, Taulelle F. Measuring distances between half-integer quadrupolar nuclei and detecting relative orientations of quadrupolar and dipolar tensors by double-quantum homonuclear dipolar recoupling nuclear magnetic resonance experiments. J Chem Phys 2008; 128:204503. [DOI: 10.1063/1.2928809] [Citation(s) in RCA: 28] [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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11
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Lo AYH, Edén M. Efficient symmetry-based homonuclear dipolar recoupling of quadrupolar spins: double-quantum NMR correlations in amorphous solids. Phys Chem Chem Phys 2008; 10:6635-44. [DOI: 10.1039/b808295b] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Murakami M, Shimizu T, Tansho M, Vinu A, Ariga K, Mori T, Takegoshi K. Two-dimensional (11)B- (11)B exchange NMR study in mesoporous boron carbon nitride at 21.8T. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2007; 31:193-6. [PMID: 17561382 DOI: 10.1016/j.ssnmr.2007.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 03/21/2007] [Accepted: 04/24/2007] [Indexed: 05/15/2023]
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13
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Ashbrook SE, Le Pollès L, Pickard CJ, Berry AJ, Wimperis S, Farnan I. First-principles calculations of solid-state17O and29Si NMR spectra of Mg2SiO4polymorphs. Phys Chem Chem Phys 2007; 9:1587-98. [PMID: 17429552 DOI: 10.1039/b618211a] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nuclear magnetic resonance (NMR) shielding and electric field gradient (EFG) tensors of three polymorphs of Mg(2)SiO(4), forsterite (alpha-Mg(2)SiO(4)), wadsleyite (beta-Mg(2)SiO(4)) and ringwoodite (gamma-Mg(2)SiO(4)), have been calculated using a density functional theory (DFT) approach with a planewave basis set and pseudopotential approximation. These Mg(2)SiO(4) polymorphs are the principal components of the Earth down to depths of 660 km and have been proposed as the hosts of water in the Earth's upper mantle and transition zone. A comparison of our calculations with single-crystal spectroscopic data in the literature for the alpha-polymorph, forsterite, shows that both the magnitude and orientation of the shielding and EFG tensors for O and Si can be obtained with sufficient accuracy to distinguish subtle differences in atomic positions between published structures. We compare calculated (17)O MAS NMR quadrupolar powder lineshapes directly with experimental lineshapes and show that we are able to reproduce them within the precision with which the NMR parameters may be determined from multi-parameter fitting. The relatively small amounts of sample available for the beta- and gamma-polymorphs, arising from the high pressures required for synthesis, has hindered the extraction of NMR parameters in previous work. The application of DFT calculations to these high-pressure polymorphs confirms previous spectral assignments, and provides deeper insight into the empirical correlations and observations reported in the literature. These first-principles methods are highly promising for the determination of local bonding in more complex materials, such as the hydrated forms of Mg(2)SiO(4), by aiding analysis of their multinuclear NMR spectra.
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Affiliation(s)
- Sharon E Ashbrook
- School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews, UK KY16 9ST.
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14
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Hung I, Howes A, Anupõld T, Samoson A, Massiot D, Smith M, Brown S, Dupree R. 27Al double rotation two-dimensional spin diffusion NMR: Complete unambiguous assignment of aluminium sites in 9Al2O3·2B2O3. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.10.085] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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16
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Genson KL, Holzmueller J, Jiang C, Xu J, Gibson JD, Zubarev ER, Tsukruk VV. Langmuir-Blodgett monolayers of gold nanoparticles with amphiphilic shells from V-shaped binary polymer arms. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:7011-5. [PMID: 16863253 DOI: 10.1021/la061163p] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Gold nanoparticles functionalized with amphiphilic polybutadiene-poly(ethylene glycol) (PB-PEG) V-shaped arms formed stable Langmuir monolayers at the air-water and the air-solid interfaces. At these interfaces, the binary arms vertically segregated into a dense polymer corona, which surrounded the gold nanoparticles, preventing their large-scale agglomeration and keeping individual nanoparticles well-separated from each other and forming flattened, pancake nanostructures. The presence of both PEG and PB chains in the close proximity to the gold core was confirmed by surface enhanced Raman spectroscopy, whereas the AFM phase contrast images revealed the presence of 2 nm gold cores surrounded by the polymer shell with the diameter of 11 nm. We suggest that the amphiphilic shell drives their spontaneous organization into discrete 2D pancake-like hybrid structures that measured up to 10 microm in diameter and had a high packing density of gold clusters.
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Affiliation(s)
- Kirsten L Genson
- Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA
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17
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Kentgens APM, van Eck ERH, Ajithkumar TG, Anupõld T, Past J, Reinhold A, Samoson A. New opportunities for double rotation NMR of half-integer quadrupolar nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 178:212-9. [PMID: 16249109 DOI: 10.1016/j.jmr.2005.09.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2005] [Revised: 09/30/2005] [Accepted: 09/30/2005] [Indexed: 05/05/2023]
Abstract
A combined approach is presented which expands the applicability of double rotation (DOR) by overcoming its most prominent disadvantages: spinning stability and sensitivity. A new design using air-bearings for the inner rotor and a computer-assisted start-up procedure allows DOR operation over in principle unlimited time at outer rotor speeds of up to 2000Hz. Sensitivity enhancement of the DOR experiment is achieved by applying amplitude-modulated adiabatic pulses such as the double frequency sweep (DFS) before pulse excitation. Repeating the DFS enhancement and signal readout several times without allowing for spin-lattice relaxation leads to sensitivity enhancements of a factor 3 for (27)Al in various minerals. As a result, it becomes possible to study low sensitivity quadrupolar nuclei and various long duration 2D measurements can be performed routinely. Spinning is adequate to suppress residual homonuclear dipolar couplings in the spectral dimension of typical quadrupolar spin systems. In 2D-exchange spectroscopy, however, homonuclear correlation can still be established through dipolar-quadrupolar cross-terms.
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Affiliation(s)
- Arno P M Kentgens
- Department of Physical Chemistry/Solid-State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, The Netherlands.
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18
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Edén M. Quadrupolar coupling selective cross-polarization in solid state NMR. Phys Chem Chem Phys 2006; 8:1994-9. [PMID: 16633686 DOI: 10.1039/b600757k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new strategy is presented for achieving selective heteronuclear polarization transfers from half-integer quadrupolar spins in magic-angle spinning (MAS) NMR. By combining cross-polarization with a recently introduced RAPT pulse sequence that selectively excites the signal of a half-integer quadrupolar nucleus based on its quadrupolar coupling constant magnitude, we demonstrate that hetero-nuclei in its close proximity may be selectively excited. Selective 23Na --> 1H polarization transfers are demonstrated in Na2MoO4 x 2 H2O, Na2HPO4 x 2 H2O and a mixture of NaHCO3 and Na2HPO4 x 2 H2O.
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Affiliation(s)
- Mattias Edén
- Physical Chemistry Division, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden.
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19
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Jiang C, Lio WY, Tsukruk VV. Surface enhanced Raman scattering monitoring of chain alignment in freely suspended nanomembranes. PHYSICAL REVIEW LETTERS 2005; 95:115503. [PMID: 16197016 DOI: 10.1103/physrevlett.95.115503] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Indexed: 05/04/2023]
Abstract
The molecular chain reorganization in freely standing membranes with encapsulated gold nanoparticles was studied with surface enhanced Raman scattering (SERS) in the course of their elastic deformations. The efficient SERS was enabled by optimizing the design of gold nanoparticle forming chainlike aggregates, thus creating an exceptional ability to conduct in situ monitoring. Small deformations resulted in the radial orientation of side phenyl rings of polymer backbones while larger deflections led to the polymer chains bridging adjacent nanoparticles within one-dimensional aggregates.
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Affiliation(s)
- Chaoyang Jiang
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, USA
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20
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Edén M, Annersten H, Zazzi Å. Pulse-assisted homonuclear dipolar recoupling of half-integer quadrupolar spins in magic-angle spinning NMR. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.04.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Ajithkumar TG, van Eck ERH, Kentgens APM. Homonuclear correlation experiments for quadrupolar nuclei, spinning away from the magic angle. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2004; 26:180-186. [PMID: 15388182 DOI: 10.1016/j.ssnmr.2004.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Revised: 03/25/2004] [Indexed: 05/24/2023]
Abstract
We present a set of homonuclear correlation experiments for half-integer quadrupolar spins in solids. In all these exchange-type experiments, the dipolar interaction is retained during the mixing time by spinning the sample at angles other than the "regular magic angle" (54.7 degrees celsius). The second-order quadrupolar interaction is averaged by different strategies for the different experiments. The multiple-quantum off magic angle spinning (MQOMAS) exchange experiment is essentially a regular MQMAS experiment where the quadrupolar interaction is averaged by combining magic angle spinning with a multiple- to single-quantum correlation scheme. The sample is spun at the magic angle at all times except during the mixing time which is added to establish homonuclear correlation. In the multiple-quantum P4 magic angle spinning (MQP4MAS) exchange experiment, the sample is spun at one of the angles at which the fourth-order Legendre polynomial vanishes (P4 magic angle), the remaining second-order quadrupolar interaction now governed by a second-rank tensor is refocussed by the multiple to single-quantum correlation scheme. In the dynamic angle spinning (DAS) exchange experiment, the second-order quadrupolar interaction is averaged by correlating the evolution from two complementary angles. These experiments are demonstrated and compared, in view of their specific advantages and disadvantages, for 23Na in the model compound Na2SO3.
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Affiliation(s)
- T G Ajithkumar
- Department of Physical Chemistry/Solid-State NMR, NSRIM Center, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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Khasawneh M, Hartman JS, Bain * AD. Direct detection of chlorine-35 multiple-quantum NMR transitions in a single crystal of sodium chlorate. Mol Phys 2004. [DOI: 10.1080/00268970410001717304] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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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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Bain AD, Khasawneh M. From NQR to NMR: The complete range of quadrupole interactions. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/cmr.a.20013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Edén M, Frydman L. Homonuclear NMR Correlations between Half-Integer Quadrupolar Nuclei Undergoing Magic-Angle Spinning. J Phys Chem B 2003. [DOI: 10.1021/jp035794t] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mattias Edén
- Chemical Physics Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Lucio Frydman
- Chemical Physics Department, Weizmann Institute of Science, Rehovot 76100, Israel
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Ajithkumar TG, Kentgens APM. Homonuclear correlation experiments of half-integer quadrupolar nuclei using multiple-quantum techniques spinning at a P(4) magic angle. J Am Chem Soc 2003; 125:2398-9. [PMID: 12603120 DOI: 10.1021/ja0292647] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new approach for obtaining structural information in half-integer quadrupolar nuclei is proposed and demonstrated. In this method, the two-dimensional multiple-quantum experiment is performed, spinning at one of the angles at which the fourth order Legendre polynomial vanishes (P4 magic angle). In such an experiment, the dipolar interaction is retained, whereas the second-order quadrupolar broadening is refocused by the MQ-1Q correlation scheme. By adding an exchange period to this pulse scheme, we performed efficient homonuclear correlation experiments in a regular magic angle spinning probe with minor modifications. The experiment is demonstrated on a model compound, and the results are briefly discussed.
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Affiliation(s)
- T G Ajithkumar
- Department of Physical Chemistry, NSRIM Center, University of Nijmegen, Toernooiveld 1, The Netherlands
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