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Karak S, Koner K, Karmakar A, Mohata S, Nishiyama Y, Duong NT, Thomas N, Ajithkumar TG, Hossain MS, Bandyopadhyay S, Kundu S, Banerjee R. Morphology Tuning via Linker Modulation: Metal-Free Covalent Organic Nanostructures with Exceptional Chemical Stability for Electrocatalytic Water Splitting. Adv Mater 2024; 36:e2209919. [PMID: 36635878 DOI: 10.1002/adma.202209919] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/26/2022] [Indexed: 06/17/2023]
Abstract
The development of synthetic routes for the formation of robust porous organic polymers (POPs) with well-defined nanoscale morphology is fundamentally significant for their practical applications. The thermodynamic characteristics that arise from reversible covalent bonding impart intrinsic chemical instability in the polymers, thereby impeding their overall potential. Herein, a unique strategy is reported to overcome the stability issue by designing robust imidazole-linked POPs via tandem reversible/irreversible bond formation. Incorporating inherent rigidity into the secondary building units leads to robust microporous polymeric nanostructures with hollow-spherical morphologies. An in-depth analysis by extensive solid-state NMR (1D and 2D) study on 1H, 13C, and 14N nuclei elucidates the bonding and reveals the high purity of the newly designed imidazole-based POPs. The nitrogen-rich polymeric nanostructures are further used as metal-free electrocatalysts for water splitting. In particular, the rigid POPs show excellent catalytic activity toward the oxygen evolution reaction (OER) with long-term durability. Among them, the most efficient OER electrocatalyst (TAT-TFBE) requires 314 mV of overpotential to drive 10 mA cm-2 current density, demonstrating its superiority over state-of-the-art catalysts (RuO2 and IrO2).
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Affiliation(s)
- Shayan Karak
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
| | - Kalipada Koner
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
| | - Arun Karmakar
- Academy of Scientific and Innovative Research, Ghaziabad, 201002, India
- Electrochemical Process Engineering (EPE) Division, CSIR-Central Electrochemical Research Institute (CECRI), Karaikudi, Tamil Nadu, 630003, India
| | - Shibani Mohata
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa, 230-0045, Japan
- JEOL Ltd., Musashino, Akishima, Tokyo, 196-8558, Japan
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa, 230-0045, Japan
- JEOL Ltd., Musashino, Akishima, Tokyo, 196-8558, Japan
| | - Neethu Thomas
- Central NMR Facility and Physical/Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. HomiBhabha Road, Pune, 411008, India
| | | | - Munshi Sahid Hossain
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
| | - Subhajit Bandyopadhyay
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
| | - Subrata Kundu
- Academy of Scientific and Innovative Research, Ghaziabad, 201002, India
- Electrochemical Process Engineering (EPE) Division, CSIR-Central Electrochemical Research Institute (CECRI), Karaikudi, Tamil Nadu, 630003, India
| | - Rahul Banerjee
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata, 741246, India
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Duong NT, Viel S, Ziarelli F, Thureau P, Mollica G. A facile approach for estimating radio-frequency field strength of low-receptivity nuclei. J Magn Reson 2024; 358:107614. [PMID: 38141495 DOI: 10.1016/j.jmr.2023.107614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/03/2023] [Accepted: 12/15/2023] [Indexed: 12/25/2023]
Abstract
Radio-frequency (RF) field calibration is essential in NMR spectroscopy. A common practice is to collect a nutation curve by varying the pulse length in a direct single-pulse excitation experiment or in a cross-polarization magic-angle spinning with a flip-back pulse experiment. From the null points on this curve, one can calculate the RF field strength. Nevertheless, the practical implementation is not always straightforward or can even be unrealizable, especially for low-receptivity nuclei owing to their associated low sensitivity. Several researchers used an approach that involves utilizing other nuclei with more sensitivity but nearly identical Larmor frequencies to that of the nucleus of interest. However, such an approach has not been a common practice so far. In this work, we have systematically revisited this approach using 3.2 mm rotors on different sets of nuclei covering a Larmor frequency range up to 80 MHz. The effect of solid- and solution-states on RF field strength measurements has been investigated. The detection of each set of nuclei is then carried out with a resonant circuit in the NMR probe consisting of identical coils and capacitors. Our methodology is illustrated by recording 135/137Ba NMR spectra of BaTiO3 without prior 135/137Ba RF field calibration.
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Affiliation(s)
| | - Stéphane Viel
- Aix Marseille Univ, CNRS, ICR, Marseille, France; Institut Universitaire de France, Paris, France
| | - Fabio Ziarelli
- Aix Marseille Univ, CNRS, Centrale Méditerranée, FSCM, Marseille, France
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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. J Magn Reson 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Koner K, Das S, Mohata S, Duong NT, Nishiyama Y, Kandambeth S, Karak S, Reddy CM, Banerjee R. Viscoelastic Covalent Organic Nanotube Fabric via Macroscopic Entanglement. J Am Chem Soc 2022; 144:16052-16059. [PMID: 35998367 DOI: 10.1021/jacs.2c06133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Covalent organic nanotubes (CONTs) are one-dimensional porous frameworks constructed from organic building blocks via dynamic covalent chemistry. CONTs are synthesized as insoluble powder that restricts their potential applications. The judicious selection of 2,2'-bipyridine-5,5'-dicarbaldehyde and tetraaminotriptycene as building blocks for TAT-BPy CONTs has led to constructing flexible yet robust and self-standing fabric up to 3 μm thickness. The TAT-BPy CONTs and TAT-BPy CONT fabric have been characterized by solid-state one-dimensional (1D) 13C CP-MAS, two-dimensional (2D) 13C-1H correlation NMR, 2D 1H-1H DQ-SQ NMR, and 2D 14N-1H correlation NMR spectroscopy. The mechanism of fabric formation has been established by using high-resolution transmission electron microscopy and scanning electron microscopy techniques. The as-synthesized viscoelastic TAT-BPy CONT fabric exhibits high mechanical strength with a reduced modulus (Er) of 8 (±3) GPa and hardness (H) of 0.6 (±0.3) GPa. Interestingly, the viscoelastic fabric shows time-dependent elastic depth recovery up to 50-70%.
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Affiliation(s)
- Kalipada Koner
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India.,Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India
| | - Susobhan Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India
| | - Shibani Mohata
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India.,Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan.,JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan
| | - Sharath Kandambeth
- Physical/Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
| | - Suvendu Karak
- Physical/Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
| | - C Malla Reddy
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India.,Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India
| | - Rahul Banerjee
- Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India.,Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Mohanpur, Kolkata 741246, India
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Duong NT, Nishiyama Y. Detection of remote proton-nitrogen correlations by 1H-detected 14N overtone solid-state NMR at fast MAS. Phys Chem Chem Phys 2022; 24:10717-10726. [PMID: 35315474 DOI: 10.1039/d2cp00155a] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Detecting proton and nitrogen correlations in solid-state nuclear magnetic resonance (NMR) is important for the structural determination of biological and chemical systems. Recent advances in proton detection-based approaches under fast magic-angle spinning have facilitated the detection of 1H-14N correlations by solid-state NMR. However, observing remote 1H-14N correlations by these approaches is still a challenge, especially for 14N sites having large quadrupolar couplings. To address this issue, we introduce the 1H-14N overtone continuous wave rotational-echo saturation-pulse double-resonance (1H-14N OT CW-RESPDOR) sequence. Unlike regular 2D correlation experiments where the indirect dimension is recorded in the time domain, the 1H-14N OT CW-RESPDOR experiment is directly observed in the frequency domain. A set of 1H-14N OT CW-RESPDOR filtered 1H spectra is recorded at varying 14N OT frequencies. Thanks to the selective nature of the 14N OT pulse, the filtered 1H spectra appear only if the 14N OT frequency hits the positions of the 14N OT central band or one of the spinning sidebands. This set of filtered 1H spectra represents a 2D 1H-14N OT correlation map. We have also investigated the optimizable parameters for CW-RESPDOR and figured out that these parameters are not strictly needed for our working magnetic field of 14.1 T. Hence, the experiment is easy to set up and requires almost no optimization. We have demonstrated the experimental feasibility of 1H-14N OT CW-RESPDOR on monoclinic L-histidine and L-alanyl L-alanine. The remote 1H-14N correlations have been efficiently detected, no matter how large the 14N quadrupolar interaction is, and agree with the crystal structures. In addition, based on the remote 1H-14N correlations from the non-protonated 14N site of L-histidine, we can unambiguously distinguish the orthorhombic and monoclinic forms.
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Affiliation(s)
- Nghia Tuan Duong
- Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan.
| | - Yusuke Nishiyama
- Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan. .,JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan
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Duong NT, Agarwal V, Nishiyama Y. Separating an overlapped 1H peak and identifying its 1H- 1H correlations with the use of single-channel 1H solid-state NMR at fast MAS. Solid State Nucl Magn Reson 2022; 117:101774. [PMID: 35051807 DOI: 10.1016/j.ssnmr.2022.101774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Fast magic-angle spinning (≥60 kHz) technique has enabled the acquisition of high-resolution 1H NMR spectra of solid materials. However, the spectral interpretation is still difficult because the 1H peaks are overlapped due to the narrow chemical shift range and broad linewidths. An additional 13C or 14N or 1H dimension possibly addresses the issues of overlapped proton resonances, but it leads to the elongated experimental time. Herein, we introduce a single-channel 1H experiment to separate the overlapped 1H peak and identify its spatially proximal 1H-1H correlations. This sequence combines selective excitation, selective 1H-1H polarization transfer by selective recoupling of protons (SERP), and broadband 1H recoupling by back-to-back (BABA) recoupling sequences. The concept for 1H separation is based on (i) the selective excitation of a well-resolved 1H peak and (ii) the selective dipolar polarization transfer from this isolated 1H peak to one of the 1H peaks in the overlapped/poor resolution region by SERP and (iii) the detection of 1H-1H correlations from these two 1H peaks to other neighboring 1Hs by BABA. We demonstrated the applicability of this approach to identify overlapped peaks on two molecules, β-L-aspartyl-l-alanine and Pioglitazone.HCl. The sequence allows the clear observation of 1H-1H correlations from an overlapped 1H peak without an additional heteronuclear dimension and ensures efficient polarization transfers that leads to twelve fold reduction in experimental time compared to 14N edited experiments. The limitation and the conditions of applicability for this approach are discussed in detail.
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Affiliation(s)
- Nghia Tuan Duong
- Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa, 230-0045, Japan
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad, Sy. No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad, 500 107, India
| | - Yusuke Nishiyama
- Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa, 230-0045, Japan; JEOL RESONANCE Inc., Akishima, Tokyo, 196-8558, Japan.
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Duong NT, Lee D, Mentink-Vigier F, Lafon O, De Paëpe G. On the use of radio-frequency offsets for improving double-quantum homonuclear dipolar recoupling of half-integer-spin quadrupolar nuclei. Magn Reson Chem 2021; 59:991-1008. [PMID: 33624858 DOI: 10.1002/mrc.5142] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Detecting proximities between nuclei is crucial for atomic-scale structure determination with nuclear magnetic resonance (NMR) spectroscopy. Different from spin-1/2 nuclei, the methodology for quadrupolar nuclei is limited for solids due to the complex spin dynamics under simultaneous magic-angle spinning (MAS) and radio-frequency irradiation. Herein, the performances of several homonuclear rotary recoupling (HORROR)-based homonuclear dipolar recoupling sequences are evaluated for 27 Al (spin-5/2). It is shown numerically and experimentally on mesoporous alumina that BR 2 2 1 outperforms the supercycled S3 sequence and its pure double-quantum (DQ) (bracketed) version, [S3 ], both in terms of DQ transfer efficiency and bandwidth. This result is surprising since the S3 sequence is among the best low-power recoupling schemes for spin-1/2. The superiority of BR 2 2 1 is thoroughly explained, and the crucial role of radio-frequency offsets during its spin dynamics is highlighted. The analytical approximation of BR 2 2 1 , derived in an offset-toggling frame, clarifies the interplay between offset and DQ efficiency, namely, the benefits of off-resonance irradiation and the trough in DQ efficiency for BR 2 2 1 when the irradiation is central between two resonances, both for spin-1/2 and half-integer-spin quadrupolar nuclei. Additionally, density matrix propagations show that the BR 2 2 1 sequence, applied to quadrupolar nuclei subject to quadrupolar interaction much larger than radio-frequency frequency field, can create single- and multiple-quantum coherences for near on-resonance irradiation. This significantly perturbs the creation of DQ coherences between central transitions of neighboring quadrupolar nuclei. This effect explains the DQ efficiency trough for near on-resonance irradiation, in the case of both cross-correlation and autocorrelation peaks. Overall, this work aids experimental acquisition of homonuclear dipolar correlation spectra of half-integer-spin quadrupolar nuclei and provides theoretical insights towards improving recoupling schemes at high magnetic field and fast MAS.
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Affiliation(s)
- Nghia Tuan Duong
- Univ. Grenoble Alpes, CEA, IRIG-MEM, Grenoble, 38000, France
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, Lille, F-59000, France
| | - Daniel Lee
- Univ. Grenoble Alpes, CEA, IRIG-MEM, Grenoble, 38000, France
| | | | - Olivier Lafon
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, Lille, F-59000, France
- Institut Universitaire de France, Paris, 75231, France
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, CEA, IRIG-MEM, Grenoble, 38000, France
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Duong NT, Aoyama Y, Kawamoto K, Yamazaki T, Nishiyama Y. Structure Solution of Nano-Crystalline Small Molecules Using MicroED and Solid-State NMR Dipolar-Based Experiments. Molecules 2021; 26:molecules26154652. [PMID: 34361806 PMCID: PMC8347922 DOI: 10.3390/molecules26154652] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/24/2021] [Accepted: 07/27/2021] [Indexed: 11/16/2022] Open
Abstract
Three-dimensional electron diffraction crystallography (microED) can solve structures of sub-micrometer crystals, which are too small for single crystal X-ray crystallography. However, R factors for the microED-based structures are generally high because of dynamic scattering. That means R factor may not be reliable provided that kinetic analysis is used. Consequently, there remains ambiguity to locate hydrogens and to assign nuclei with close atomic numbers, like carbon, nitrogen, and oxygen. Herein, we employed microED and ssNMR dipolar-based experiments together with spin dynamics numerical simulations. The NMR dipolar-based experiments were 1H-14N phase-modulated rotational-echo saturation-pulse double-resonance (PM-S-RESPDOR) and 1H-1H selective recoupling of proton (SERP) experiments. The former examined the dephasing effect of a specific 1H resonance under multiple 1H-14N dipolar couplings. The latter examined the selective polarization transfer between a 1H-1H pair. The structure was solved by microED and then validated by evaluating the agreement between experimental and calculated dipolar-based NMR results. As the measurements were performed on 1H and 14N, the method can be employed for natural abundance samples. Furthermore, the whole validation procedure was conducted at 293 K unlike widely used chemical shift calculation at 0 K using the GIPAW method. This combined method was demonstrated on monoclinic l-histidine.
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Affiliation(s)
- Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan;
| | | | | | - Toshio Yamazaki
- RIKEN Center for Biosystems Dynamics Research, RIKEN, Yokohama, Kanagawa 230-0045, Japan;
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan;
- JEOL RESONANCE Inc., Akishima, Tokyo 196-8558, Japan
- Correspondence:
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Potnuru LR, Duong NT, Sasank B, Raran-Kurussi S, Nishiyama Y, Agarwal V. Selective 1H- 1H recoupling via symmetry sequences in fully protonated samples at fast magic angle spinning. J Magn Reson 2021; 328:107004. [PMID: 34049237 DOI: 10.1016/j.jmr.2021.107004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/09/2021] [Accepted: 05/10/2021] [Indexed: 05/08/2023]
Abstract
Proton-detected solid-state NMR at fast Magic Angle Spinning (MAS) is becoming the norm to characterize molecules. Routinely 1H-1H and 1H-X dipolar couplings are used to characterize the structure and dynamics of molecules. Selective proton recoupling techniques are emerging as a method for structural characterization via estimation of qualitative and quantitative distances. In the present study, we demonstrate through numerical simulations and experiments that the well-characterized CNvn sequences can also be tailored for selective recoupling of proton spins by employing C elements of the type (β)Φ(4β)Φ+π(3β)Φ. Herein, several CNvn sequences were examined through numerical simulations and experiments. C614 recoupling sequence with a modified POST-element ((β)Φ(4β)Φ+π(3β)Φ) shows selective polarization transfer efficiencies on the order of 40-50% between various proton spin pairs in fully protonated samples at rf amplitudes ranging from 0.3 to 0.8 times the MAS frequency. These selective recoupling sequences have been labeled as frequency-selective-CNvn sequences. The extent of selectivity, polarization transfer efficiency and the feasibility of experimentally measuring proton-proton distances in fully protonated samples are explored here. The development of efficient and robust selective 1H-1H recoupling experiments is required to structurally characterize molecules without artificial isotope enrichment or the need for diffracting crystals.
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Affiliation(s)
- Lokeswara Rao Potnuru
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad, Sy. No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India
| | - Nghia Tuan Duong
- Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Budaraju Sasank
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad, Sy. No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India; Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Mohali 140306, India
| | - Sreejith Raran-Kurussi
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad, Sy. No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India
| | - Yusuke Nishiyama
- Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad, Sy. No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India.
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Duong NT, Gan Z, Nishiyama Y. Selective 1H- 14N Distance Measurements by 14N Overtone Solid-State NMR Spectroscopy at Fast MAS. Front Mol Biosci 2021; 8:645347. [PMID: 33898521 PMCID: PMC8061749 DOI: 10.3389/fmolb.2021.645347] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 01/28/2021] [Indexed: 01/25/2023] Open
Abstract
Accurate distance measurements between proton and nitrogen can provide detailed information on the structures and dynamics of various molecules. The combination of broadband phase-modulated (PM) pulse and rotational-echo saturation-pulse double-resonance (RESPDOR) sequence at fast magic-angle spinning (MAS) has enabled the measurement of multiple 1H-14N distances with high accuracy. However, complications may arise when applying this sequence to systems with multiple inequivalent 14N nuclei, especially a single 1H sitting close to multiple 14N atoms. Due to its broadband characteristics, the PM pulse saturates all 14N atoms; hence, the single 1H simultaneously experiences the RESPDOR effect from multiple 1H-14N couplings. Consequently, no reliable H-N distances are obtained. To overcome the problem, selective 14N saturation is desired, but it is difficult because 14N is an integer quadrupolar nucleus. Alternatively, 14N overtone (OT) NMR spectroscopy can be employed owing to its narrow bandwidth for selectivity. Moreover, owing to the sole presence of two energy levels (m = ± 1), the 14N OT spin dynamics behaves similarly to that of spin-1/2. This allows the interchangeability between RESPDOR and rotational-echo double-resonance (REDOR) since their principles are the same except the degree of 14N OT population transfer; saturation for the former whereas inversion for the latter. As the ideal saturation/inversion is impractical due to the slow and orientation-dependent effective nutation of 14N OT, the working condition is usually an intermediate between REDOR and RESPDOR. The degree of 14N OT population transfer can be determined from the results of protons with short distances to 14N and then can be used to obtain long-distance determination of other protons to the same 14N site. Herein, we combine the 14N OT and REDOR/RESPDOR to explore the feasibility of selective 1H-14N distance measurements. Experimental demonstrations on simple biological compounds of L-tyrosine.HCl, N-acetyl-L-alanine, and L-alanyl-L-alanine were performed at 14.1 T and MAS frequency of 62.5 kHz. The former two consist of a single 14N site, whereas the latter consists of two 14N sites. The experimental optimizations and reliable fittings by the universal curves are described. The extracted 1H-14N distances by OT-REDOR are in good agreement with those determined by PM-RESPDOR and diffraction techniques.
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Affiliation(s)
- Nghia Tuan Duong
- NMR Science and Development Division, RIKEN SPring-8 Center, Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Japan
| | - Zhehong Gan
- Centre of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Tallahassee, FL, United States
| | - Yusuke Nishiyama
- NMR Science and Development Division, RIKEN SPring-8 Center, Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Japan
- JEOL RESONANCE Inc., Tokyo, Japan
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Matsunaga T, Kanazawa J, Ichikawa T, Harada M, Nishiyama Y, Duong NT, Matsumoto T, Miyamoto K, Uchiyama M. α‐Cyclodextrin Encapsulation of Bicyclo[1.1.1]pentane Derivatives: A Storable Feedstock for Preparation of [1.1.1]Propellane. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tadafumi Matsunaga
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Junichiro Kanazawa
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Tomohiro Ichikawa
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Mei Harada
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center and SPring-8 Center RIKEN, Tsurumi Yokohama Kanagawa 230-0045 Japan
- JEOL RESONANCE Inc. 3-1-2 Musashino, Akishima Tokyo 196-8558 Japan
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center and SPring-8 Center RIKEN, Tsurumi Yokohama Kanagawa 230-0045 Japan
| | - Takashi Matsumoto
- Rigaku Corporation 3-9-12 Matsubara-cho, Akishima Tokyo 196-8666 Japan
| | - Kazunori Miyamoto
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
- Cluster for Pioneering Research (CPR) RIKEN 2-1 Hirosawa, Wako-shi Saitama 351-0198 Japan
- Research Initiative for Supra-Materials (RISM) Shinshu University 3-15-1 Tokida, Ueda Nagano 386-8567 Japan
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Matsunaga T, Kanazawa J, Ichikawa T, Harada M, Nishiyama Y, Duong NT, Matsumoto T, Miyamoto K, Uchiyama M. α-Cyclodextrin Encapsulation of Bicyclo[1.1.1]pentane Derivatives: A Storable Feedstock for Preparation of [1.1.1]Propellane. Angew Chem Int Ed Engl 2021; 60:2578-2582. [PMID: 33205884 DOI: 10.1002/anie.202014997] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Indexed: 12/15/2022]
Abstract
The bicyclo[1.1.1]pentane (BCP) scaffold is useful in medicinal chemistry, and many protocols are available for synthesizing BCP derivatives from [1.1.1]propellane. Here, we report (1) the α-cyclodextrin (α-CD) encapsulation of BCP derivatives, affording a stable, readily storable material from which BCPs can be easily and quantitatively recovered and (2) new and simple protocols for deiodination reaction of 1,3-diiodo BCP to afford [1.1.1]propellane in protic/aprotic/polar/non-polar solvents. The combination of these methodologies enables simple, on-demand preparation of [1.1.1]propellane in various solvents under mild conditions from α-CD capsules containing 1,3-diiodo BCP.
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Affiliation(s)
- Tadafumi Matsunaga
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Junichiro Kanazawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Tomohiro Ichikawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Mei Harada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center and SPring-8 Center, RIKEN, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan.,JEOL RESONANCE Inc., 3-1-2 Musashino, Akishima, Tokyo, 196-8558, Japan
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center and SPring-8 Center, RIKEN, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Takashi Matsumoto
- Rigaku Corporation, 3-9-12 Matsubara-cho, Akishima, Tokyo, 196-8666, Japan
| | - Kazunori Miyamoto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Cluster for Pioneering Research (CPR), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan.,Research Initiative for Supra-Materials (RISM), Shinshu University, 3-15-1 Tokida, Ueda, Nagano, 386-8567, Japan
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Matsunaga T, Kanazawa J, Ichikawa T, Harada M, Nishiyama Y, Duong NT, Matsumoto T, Miyamoto K, Uchiyama M. Cover Picture: α‐Cyclodextrin Encapsulation of Bicyclo[1.1.1]pentane Derivatives: A Storable Feedstock for Preparation of [1.1.1]Propellane (Angew. Chem. Int. Ed. 5/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/anie.202016348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Tadafumi Matsunaga
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Junichiro Kanazawa
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Tomohiro Ichikawa
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Mei Harada
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center and SPring-8 Center RIKEN, Tsurumi Yokohama Kanagawa 230-0045 Japan
- JEOL RESONANCE Inc. 3-1-2 Musashino, Akishima Tokyo 196-8558 Japan
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center and SPring-8 Center RIKEN, Tsurumi Yokohama Kanagawa 230-0045 Japan
| | - Takashi Matsumoto
- Rigaku Corporation 3-9-12 Matsubara-cho, Akishima Tokyo 196-8666 Japan
| | - Kazunori Miyamoto
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
- Cluster for Pioneering Research (CPR) RIKEN 2-1 Hirosawa, Wako-shi Saitama 351-0198 Japan
- Research Initiative for Supra-Materials (RISM) Shinshu University 3-15-1 Tokida, Ueda Nagano 386-8567 Japan
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Matsunaga T, Kanazawa J, Ichikawa T, Harada M, Nishiyama Y, Duong NT, Matsumoto T, Miyamoto K, Uchiyama M. Titelbild: α‐Cyclodextrin Encapsulation of Bicyclo[1.1.1]pentane Derivatives: A Storable Feedstock for Preparation of [1.1.1]Propellane (Angew. Chem. 5/2021). Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202016348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Tadafumi Matsunaga
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Junichiro Kanazawa
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Tomohiro Ichikawa
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Mei Harada
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center and SPring-8 Center RIKEN, Tsurumi Yokohama Kanagawa 230-0045 Japan
- JEOL RESONANCE Inc. 3-1-2 Musashino, Akishima Tokyo 196-8558 Japan
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center and SPring-8 Center RIKEN, Tsurumi Yokohama Kanagawa 230-0045 Japan
| | - Takashi Matsumoto
- Rigaku Corporation 3-9-12 Matsubara-cho, Akishima Tokyo 196-8666 Japan
| | - Kazunori Miyamoto
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
- Cluster for Pioneering Research (CPR) RIKEN 2-1 Hirosawa, Wako-shi Saitama 351-0198 Japan
- Research Initiative for Supra-Materials (RISM) Shinshu University 3-15-1 Tokida, Ueda Nagano 386-8567 Japan
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Potnuru LR, Duong NT, Ahlawat S, Raran-Kurussi S, Ernst M, Nishiyama Y, Agarwal V. Accuracy of 1H- 1H distances measured using frequency selective recoupling and fast magic-angle spinning. J Chem Phys 2020; 153:084202. [PMID: 32872876 DOI: 10.1063/5.0019717] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Selective recoupling of protons (SERP) is a method to selectively and quantitatively measure magnetic dipole-dipole interaction between protons and, in turn, the proton-proton distance in solid-state samples at fast magic-angle spinning. We present a bimodal operator-based Floquet approach to describe the numerically optimized SERP recoupling sequence. The description calculates the allowed terms in the first-order effective Hamiltonian, explains the origin of selectivity during recoupling, and shows how different terms are modulated as a function of the radio frequency amplitude and the phase of the sequence. Analytical and numerical simulations have been used to evaluate the effect of higher-order terms and offsets on the polarization transfer efficiency and quantitative distance measurement. The experimentally measured 1H-1H distances on a fully protonated thymol sample are ∼10%-15% shorter than those reported from diffraction studies. A semi-quantitative model combined with extensive numerical simulations is used to rationalize the effect of the third-spin and the role of different parameters in the experimentally observed shorter distances. Measurements at high magnetic fields improve the match between experimental and diffraction distances. The measurement of 1H-1H couplings at offsets different from the SERP-offset has also been explored. Experiments were also performed on a perdeuterated ubiquitin sample to demonstrate the feasibility of simultaneously measuring multiple quantitative distances and to evaluate the accuracy of the measured distance in the absence of multispin effects. The estimation of proton-proton distances provides a boost to structural characterization of small pharmaceuticals and biomolecules, given that the positions of protons are generally not well defined in x-ray structures.
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Affiliation(s)
- Lokeswara Rao Potnuru
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India
| | - Nghia Tuan Duong
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Sahil Ahlawat
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India
| | - Sreejith Raran-Kurussi
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India
| | - Matthias Ernst
- Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Yusuke Nishiyama
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India
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Duong NT, Raran-Kurussi S, Nishiyama Y, Agarwal V. Can proton-proton recoupling in fully protonated solids provide quantitative, selective and efficient polarization transfer? J Magn Reson 2020; 317:106777. [PMID: 32619889 DOI: 10.1016/j.jmr.2020.106777] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/19/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Dipolar recoupling sequences have been used to probe spatial proximity of nuclear spins and were traditionally designed to probe rare spins such as 13C and/or 15N nuclei. The multi-spin dipolar-coupling network of the rare spins is weak due to smaller couplings and large chemical shift dispersion. Therefore, the recoupling approaches were tailored to design offset compensated or broadband sequences. In contrast, protons have a substantially stronger dipolar-coupling network and much narrower chemical shift range. Broadband recoupling sequences such as radio-frequency driven recoupling (RFDR), back-to-back (BABA), and lab frame proton-proton spin diffusion have been routinely used to characterize the structures of protein/macromolecules and small molecules. Recently selective 1H-1H recoupling sequences have been proposed that combine chemical shift offset of the resolved proton spectrum (at fast MAS) with first- and second-order dipolar recoupling Hamiltonians to obtain quantitative and qualitative proton distances, respectively. Herein, we evaluate the performances of broadband and selective proton recoupling sequences such as finite pulse RFDR (fp-RFDR), band-selective spectral spin diffusion (BASS-SD), second-order cross-polarization (SOCP), and selective recoupling of proton (SERP) in terms of the selectivity and efficiency of 1H-1H polarization transfers in a dense network of proton spins and explore the possibility of measuring 1H-1H distances. We use theoretical considerations, numerical simulations, and experiments to support the distinct advantages and disadvantages of each recoupling sequence. Experiments were performed on L-histidine.HCl.H2O at a MAS frequency of 71.43 kHz. This study rationalizes the proper selection of 1H-1H recoupling sequences when working with fully protonated solids.
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Affiliation(s)
- Nghia Tuan Duong
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Sreejith Raran-Kurussi
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Sy. No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India
| | - Yusuke Nishiyama
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, Sy. No. 36/P, Gopanpally, Ranga Reddy District, Hyderabad 500 107, India.
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Duong NT, Rossi F, Makrinich M, Goldbourt A, Chierotti MR, Gobetto R, Nishiyama Y. Accurate 1H- 14N distance measurements by phase-modulated RESPDOR at ultra-fast MAS. J Magn Reson 2019; 308:106559. [PMID: 31345769 DOI: 10.1016/j.jmr.2019.07.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
The combination of a phase-modulated (PM) saturation pulse and symmetry-based dipolar recoupling into a rotational-echo saturation-pulse double-resonance (RESPDOR) sequence has been employed to measure 1H-14N distances. Such a measurement is challenging owing to the quadrupolar interaction of 14N nucleus and the intense 1H-1H homonuclear dipolar interactions. Thanks to the recent advances in probe technology, the homonuclear dipolar interaction can be sufficiently suppressed at a fast MAS frequency (νR ≥ 60 kHz). PM pulse is robust to large variations of parameters on quadrupolar spins, but it has not been demonstrated under very fast MAS conditions. On the other hand, the RESPDOR sequence is applicable to such condition when it employs symmetry-based pulses during the recoupling period, but a prior knowledge on the system is required. In this article, we demonstrated the PM-RESPDOR combination for providing accurate 1H-14N distances at a very fast MAS frequency of 70 kHz on two samples, namely L-tyrosine⋅HCl and N-acetyl-L-alanine. This sequence, supported by simulations and experiments, has shown its feasibility at νR = 70 kHz as well as the robustness to the 14N quadrupolar interaction. It is applicable to a wide range of 1H-14N dipolar coupling constants when a radio frequency field on the 14N channel is approximately 80 kHz or more, while the PM pulse length lasts 10 rotor periods. For the first time, multiple 1H-14N heteronuclear dipolar couplings, thus multiple quantitative distances, are simultaneously and reliably extracted by fitting the experimental fraction curves with the analytical expression. The size of the 1H-14N dipolar interaction is solely used as a fitting parameter. These determined distances are in excellent agreement with those derived from diffraction techniques.
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Affiliation(s)
- Nghia Tuan Duong
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Federica Rossi
- Department of Chemistry and NIS Centre, University of Torino, V.P. Giuria 7, 10125, Italy
| | - Maria Makrinich
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Amir Goldbourt
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Michele R Chierotti
- Department of Chemistry and NIS Centre, University of Torino, V.P. Giuria 7, 10125, Italy
| | - Roberto Gobetto
- Department of Chemistry and NIS Centre, University of Torino, V.P. Giuria 7, 10125, Italy
| | - Yusuke Nishiyama
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
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Kadota K, Duong NT, Nishiyama Y, Sivaniah E, Horike S. Synthesis of porous coordination polymers using carbon dioxide as a direct source. Chem Commun (Camb) 2019; 55:9283-9286. [PMID: 31312827 DOI: 10.1039/c9cc04771a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Porous coordination polymers (PCPs) were synthesized by using CO2 and metal borohydrides as precursors. Borohydrides converted CO2 into bridging ligands such as formate (HCO2-) or formylhydroborate ([BH(OCHO)3]-) which are available to construct porous architectures; one of them shows 380 m2 g-1 surface area.
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Affiliation(s)
- Kentaro Kadota
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Nghia Tuan Duong
- NMR Science and Development Division, RIKEN SPring-8 Center and RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Nishiyama
- NMR Science and Development Division, RIKEN SPring-8 Center and RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan and JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan
| | - Easan Sivaniah
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan and Institute for Integrated Cell-Material Sciences, Institute for Advanced Study, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Satoshi Horike
- Institute for Integrated Cell-Material Sciences, Institute for Advanced Study, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan. and AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory (ChEM-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan and Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan and Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand
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Duong NT, Trébosc J, Lafon O, Amoureux JP. Improved sensitivity and quantification for 29Si NMR experiments on solids using UDEFT (Uniform Driven Equilibrium Fourier Transform). Solid State Nucl Magn Reson 2019; 100:52-62. [PMID: 30959243 DOI: 10.1016/j.ssnmr.2019.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/21/2019] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
We demonstrate the possibility to use UDEFT (Uniform Driven Equilibrium Fourier Transform) technique in order to improve the sensitivity and the quantification of one-dimensional 29Si NMR experiments under magic-angle spinning (MAS). We derive an analytical expression of the signal-to-noise ratios of UDEFT and single-pulse (SP) experiments subsuming the contributions of transient and steady-state regimes. Using numerical spin dynamics simulations and experiments on 29Si-enriched amorphous silica and borosilicate glass, we show that 59180298059180 refocusing composite π-pulse and the adiabatic inversion using tanh/tan modulation improve the robustness of UDEFT technique to rf-inhomogeneity, offset, and chemical shift anisotropy. These pulses combined with a two-step phase cycle limit the pulse imperfections and the artifacts produced by stimulated echoes. The sensitivity of SP, UDEFT and CPMG (Carr-Purcell-Meiboom-Gill) techniques are experimentally compared on functionalized and non-functionalized mesoporous silica. Furthermore, experiments on a flame retardant material prove that UDEFT technique provides a better quantification of 29Si sites with higher sensitivity than SP method.
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Affiliation(s)
- Nghia Tuan Duong
- Univ. Lille, Centrale Lille, ENSCL, Univ. Artois, CNRS-8181, UCCS - Unit of Catalysis and Chemistry of Solids, F-59000 Lille, France
| | - Julien Trébosc
- Univ. Lille, Centrale Lille, ENSCL, Univ. Artois, CNRS-8181, UCCS - Unit of Catalysis and Chemistry of Solids, F-59000 Lille, France; Univ. Lille, CNRS-FR2638, Fédération Chevreul, F-59000 Lille, France.
| | - Olivier Lafon
- Univ. Lille, Centrale Lille, ENSCL, Univ. Artois, CNRS-8181, UCCS - Unit of Catalysis and Chemistry of Solids, F-59000 Lille, France; Institut Universitaire de France, 1 rue Descartes, F-75231 Paris, France
| | - Jean-Paul Amoureux
- Univ. Lille, Centrale Lille, ENSCL, Univ. Artois, CNRS-8181, UCCS - Unit of Catalysis and Chemistry of Solids, F-59000 Lille, France; Bruker Biospin, 34 rue de l'industrie, F-67166 Wissembourg, France.
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Zhang R, Duong NT, Nishiyama Y. Resolution enhancement and proton proximity probed by 3D TQ/DQ/SQ proton NMR spectroscopy under ultrafast magic-angle-spinning beyond 70 kHz. J Magn Reson 2019; 304:78-86. [PMID: 31146121 DOI: 10.1016/j.jmr.2019.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/15/2019] [Accepted: 05/18/2019] [Indexed: 06/09/2023]
Abstract
Proton nuclear magnetic resonance (NMR) in solid state has gained significant attention in recent years due to the remarkable resolution and sensitivity enhancement afforded by ultrafast magic-angle-spinning (MAS). In spite of the substantial suppression of 1H-1H dipolar couplings, the proton spectral resolution is still poor compared to that of 13C or 15N NMR, rendering it challenging for the structural and conformational analysis of complex chemicals or biological solids. Herein, by utilizing the benefits of double-quantum (DQ) and triple-quantum (TQ) coherences, we propose a 3D single-channel pulse sequence that correlates proton triple-quantum/double-quantum/single-quantum (TQ/DQ/SQ) chemical shifts. In addition to the two-spin proximity information, this 3D TQ/DQ/SQ pulse sequence enables more reliable extraction of three-spin proximity information compared to the regular 2D TQ/SQ correlation experiment, which could aid in revealing the proton network in solids. Furthermore, the TQ/DQ slice taken at a specific SQ chemical shift only reveals the local correlations to the corresponding SQ chemical shift, and thus it enables accurate assignments of the proton peaks along the TQ and DQ dimensions and simplifies the interpretation of proton spectra especially for dense proton networks. The high performance of this 3D pulse sequence is well demonstrated on small compounds, L-alanine and a tripeptide, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (MLF). We expect that this new methodology can inspire the development of multidimensional solid-state NMR pulse sequences using the merits of TQ and DQ coherences and enable high-throughput investigations of complex solids using abundant protons.
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Affiliation(s)
- Rongchun Zhang
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Molecular Science and Engineering, South China University of Technology, Guangzhou 510640, PR China.
| | - Nghia Tuan Duong
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Nishiyama
- NMR Science and Development Division, RIKEN SPring-8 Center, and Nano-Crystallography Unit, RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
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21
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Kadota K, Duong NT, Nishiyama Y, Sivaniah E, Kitagawa S, Horike S. Borohydride-containing coordination polymers: synthesis, air stability and dehydrogenation. Chem Sci 2019; 10:6193-6198. [PMID: 31360426 PMCID: PMC6585883 DOI: 10.1039/c9sc00731h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/11/2019] [Indexed: 11/24/2022] Open
Abstract
Control of the reactivity of hydride (H-) in crystal structures has been a challenge because of its strong electron-donating ability and reactivity with protic species. For metal borohydrides, the dehydrogenation activity and air stability are in a trade-off, and control of the reactivity of BH4 - has been demanded. For this purpose, we synthesize a series of BH4 --based coordination polymers/metal-organic frameworks. The reactivity of BH4 - in the structures is regulated by coordination geometry and neighboring ligands, and one of the compounds [Zn(BH4)2(dipyridylpropane)] exhibits both high dehydrogenation reactivity (1.4 wt% at 179 °C) and high air stability (50 RH% at 25 °C, 7 days). Single crystal X-ray diffraction analysis reveals that H δ+···H δ- dihydrogen interactions and close packing of hydrophobic ligands are the key for the reactivity and stability. The dehydrogenation mechanism is investigated by temperature-programmed desorption, in situ synchrotron PXRD and solid-state NMR.
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Affiliation(s)
- Kentaro Kadota
- Department of Molecular Engineering , Graduate School of Engineering , Kyoto University , Katsura, Nishikyo-ku , Kyoto 615-8510 , Japan
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center , Tsurumi , Yokohama , Kanagawa 230-0045 , Japan
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center , Tsurumi , Yokohama , Kanagawa 230-0045 , Japan
- JEOL RESONANCE Inc. , Musashino , Akishima , Tokyo 196-8558 , Japan
| | - Easan Sivaniah
- Department of Molecular Engineering , Graduate School of Engineering , Kyoto University , Katsura, Nishikyo-ku , Kyoto 615-8510 , Japan
- Institute for Integrated Cell-Material Sciences , Institute for Advanced Study , Kyoto University , Yoshida, Sakyo-ku , Kyoto 606-8501 , Japan .
| | - Susumu Kitagawa
- Institute for Integrated Cell-Material Sciences , Institute for Advanced Study , Kyoto University , Yoshida, Sakyo-ku , Kyoto 606-8501 , Japan .
| | - Satoshi Horike
- Institute for Integrated Cell-Material Sciences , Institute for Advanced Study , Kyoto University , Yoshida, Sakyo-ku , Kyoto 606-8501 , Japan .
- AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory (ChEM-OIL) , National Institute of Advanced Industrial Science and Technology (AIST) , Yoshida-Honmachi, Sakyo-ku , Kyoto 606-8501 , Japan
- Department of Synthetic Chemistry and Biological Chemistry , Graduate School of Engineering , Kyoto University , Katsura, Nishikyo-ku , Kyoto 615-8510 , Japan
- Department of Materials Science and Engineering , School of Molecular Science and Engineering , Vidyasirimedhi Institute of Science and Technology , Rayong 21210 , Thailand
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22
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Zhang C, Yang Z, Duong NT, Li X, Nishiyama Y, Wu Q, Zhang R, Sun P. Using Dynamic Bonds to Enhance the Mechanical Performance: From Microscopic Molecular Interactions to Macroscopic Properties. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00503] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Chi Zhang
- Key Laboratory of Functional Polymer Materials of the Ministry of Education and College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Zhijun Yang
- Key Laboratory of Functional Polymer Materials of the Ministry of Education and College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Xiaohui Li
- School of Materials Science and Engineering, and Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin 300072, P. R. China
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
- JEOL Resonance Inc., Musashino, Akishima, Tokyo 196-8558, Japan
- NMR Science and Development Division, RIKEN SPring-8 Center, Yokohama, Kanagawa 230-0045, Japan
| | - Qiang Wu
- Key Laboratory of Functional Polymer Materials of the Ministry of Education and College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Rongchun Zhang
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Molecular Science and Engineering, South China University of Technology, Guangzhou 510640, P. R. China
| | - Pingchuan Sun
- Key Laboratory of Functional Polymer Materials of the Ministry of Education and College of Chemistry, Nankai University, Tianjin 300071, P. R. China
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, P. R. China
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23
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Rossi F, Duong NT, Pandey MK, Chierotti MR, Gobetto R, Nishiyama Y. Determination of the 15 N chemical shift anisotropy in natural abundance samples by proton-detected 3D solid-state NMR under ultrafast MAS of 70 kHz. Magn Reson Chem 2019; 57:294-303. [PMID: 30684385 DOI: 10.1002/mrc.4841] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/17/2019] [Accepted: 01/19/2019] [Indexed: 06/09/2023]
Abstract
Chemical shift anisotropy (CSA) is a sensitive probe of electronic environment at a nucleus, and thus, it offers deeper insights into detailed structural and dynamic properties of different systems, for example, chemical, biological, and materials. Over the years, massive efforts have been made to develop recoupling methods that reintroduce CSA interaction under magic angle spinning (MAS) conditions. Most of them require slow or moderate MAS (≤20 kHz) and isotopically enriched samples. On the other hand, to the best of the authors' knowledge, no 13 C or 15 N CSA recoupling schemes at ultrafast MAS (≥60 kHz) suitable for cost-effective natural abundant samples have been developed. We present here a proton-detected 3D 15 N CS/15 N CSA/1 H CS correlation experiment which employs 1 H indirect detection for sensitivity enhancement and a γ-encoded RNnν -symmetry-based CSA recoupling scheme. In particular, two different symmetries, that is, R837 and R1049 , are first tested, in a 2D 15 N CSA/1 H CS version, on [U-15 N]-L-histidine·HCl·H2 O as a model sample under 70 kHz MAS. Then the 3D experiment is applied on glycyl-L-alanine at natural abundance, resulting in site-resolved 15 N CSA lineshapes from which CSA parameters are retrieved by SIMPSON numerical fittings. We demonstrate that this 3D R-symmetry-based pulse sequence is highly robust with respect to wide-range offset mismatches and weakly dependent to rf inhomogeneity within mis-sets of ±10% from the theoretical value.
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Affiliation(s)
- Federica Rossi
- Department of Chemistry and NIS Centre, University of Torino, V. P. Giuria 7, Torino, Italy
| | | | - Manoj Kumar Pandey
- Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab, India
| | - Michele R Chierotti
- Department of Chemistry and NIS Centre, University of Torino, V. P. Giuria 7, Torino, Italy
| | - Roberto Gobetto
- Department of Chemistry and NIS Centre, University of Torino, V. P. Giuria 7, Torino, Italy
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa, Japan
- NMR Science and Development Division, RIKEN SPring-8 Center, Yokohama, Kanagawa, Japan
- JEOL RESONANCE Inc., Musashino, Akishima, Tokyo, Japan
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24
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Jensen ND, Duong NT, Bolanz R, Nishiyama Y, Rasmussen CA, Gottlicher J, Steininger R, Prevot V, Nielsen UG. Synthesis and Structural Characterization of a Pure ZnAl 4(OH) 12(SO 4)·2.6H 2O Layered Double Hydroxide. Inorg Chem 2019; 58:6114-6122. [PMID: 30986049 DOI: 10.1021/acs.inorgchem.9b00390] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The phase purity of a series of ZnAl4(OH)12SO4· nH2O layered double hydroxides (ZnAl4-LDH) obtained from a reaction of bayerite (Al(OH)3) with an excess of zinc(II) sulfate under hydrothermal conditions was investigated as a function of the reaction temperature, the duration of the hydrothermal treatment, and the zinc(II) concentration. The product quality, i.e., crystalline impurities, Al impurities, and bulk Zn:Al ratio, were assessed by powder X-ray diffraction (PXRD), 27Al MAS NMR, and elemental analysis. Structural characterization of a stoichiometric ZnAl4-LDH (120 °C, 9 days, and 2.8 M Zn(II)) showed a well-defined structure of the metal ion layer as evidenced by a single, well-defined Zn environment: i.e., no Zn substitution on the Al sites according to Zn k-edge EXAFS and PXRD. Furthermore, nearly all of the 12 different 1H atoms in the -OH groups and 4 27Al resonances could be assigned using 1H,27Al NMR correlation experiments recorded with ultrafast MAS. The interlayer water content is variable on the basis of thermogravimetric analysis and changes in the 1H MAS NMR spectra with temperature. A composition of ZnAl4(OH)12(SO4)·2.6H2O was obtained from a combination of these techniques and confirmed that ZnAl4-LDH is isostructural with the mineral nickelalumite (NiAl4(OH)12SO4·3H2O).
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Affiliation(s)
- Nicholai Daugaard Jensen
- Department of Physics, Chemistry, and Pharmacy , University of Southern Denmark , Campusvej 55 , 5230 Odense M , Denmark
| | - Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center , RIKEN , Yokohama , Kanagawa 230-0045 , Japan
| | - Ralph Bolanz
- Friedrich-Schiller-University , Institute of Geosciences , Carl-Zeiss-Promenade 10 , 07745 Jena , Germany
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center , RIKEN , Yokohama , Kanagawa 230-0045 , Japan.,NMR Science and Development Division , RIKEN SPring-8 Center , Tsurumi, Yokohama , Kanagawa 230-0045 , Japan.,JEOL RESONANCE Inc. , Musashino , Akisma, Tokyo 186-8558 , Japan
| | - Camilla Aistrup Rasmussen
- Department of Physics, Chemistry, and Pharmacy , University of Southern Denmark , Campusvej 55 , 5230 Odense M , Denmark
| | - Jorg Gottlicher
- Karlsruhe Institute of Technology , Institute for Photon Science and Synchrotron Radiation (IPS) , Hermann-von-Helmholtz Platz 1 , D-79344 Eggenstein-Leopoldshafen , Germany
| | - Ralph Steininger
- Karlsruhe Institute of Technology , Institute for Photon Science and Synchrotron Radiation (IPS) , Hermann-von-Helmholtz Platz 1 , D-79344 Eggenstein-Leopoldshafen , Germany
| | - Vanessa Prevot
- Université Clermont Auvergne , CNRS, SIGMA Clermont, ICCF , F-63000 Clermont-Ferrand , France
| | - Ulla Gro Nielsen
- Department of Physics, Chemistry, and Pharmacy , University of Southern Denmark , Campusvej 55 , 5230 Odense M , Denmark
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25
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Nagarkar SS, Kurasho H, Duong NT, Nishiyama Y, Kitagawa S, Horike S. Crystal melting and glass formation in copper thiocyanate based coordination polymers. Chem Commun (Camb) 2019; 55:5455-5458. [DOI: 10.1039/c9cc02172h] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The melting point of Cu+ coordination polymer crystals is controlled by ligands, and the reversible crystal-to-glass state is observed.
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Affiliation(s)
- Sanjog S. Nagarkar
- AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory (ChEM-OIL)
- National Institute of Advanced Industrial Science and Technology (AIST)
- Kyoto 606-8501
- Japan
| | - Haruna Kurasho
- Department of Synthetic Chemistry and Biological Chemistry
- Graduate School of Engineering
- Kyoto University
- Kyoto 615-8510
- Japan
| | - Nghia Tuan Duong
- NMR Science and Development Division
- RIKEN SPring-8 Center and Nano-Crystallography Unit
- RIKEN-JEOL Collaboration Center
- Yokohama
- Japan
| | - Yusuke Nishiyama
- NMR Science and Development Division
- RIKEN SPring-8 Center and Nano-Crystallography Unit
- RIKEN-JEOL Collaboration Center
- Yokohama
- Japan
| | - Susumu Kitagawa
- Institute for Integrated Cell-Material Sciences
- Institute for Advanced Study, Kyoto University
- Kyoto 606-8501
- Japan
| | - Satoshi Horike
- AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory (ChEM-OIL)
- National Institute of Advanced Industrial Science and Technology (AIST)
- Kyoto 606-8501
- Japan
- Department of Synthetic Chemistry and Biological Chemistry
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26
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Duong NT, Raran-Kurussi S, Nishiyama Y, Agarwal V. Quantitative 1H- 1H Distances in Protonated Solids by Frequency-Selective Recoupling at Fast Magic Angle Spinning NMR. J Phys Chem Lett 2018; 9:5948-5954. [PMID: 30247041 DOI: 10.1021/acs.jpclett.8b02189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy of protons in protonated solids is challenging. Fast magic angle spinning (MAS) and homonuclear decoupling schemes, in conjunction, with high magnetic fields have improved the proton resolution. However, experiments to quantitatively measure 1H-1H distances still remain elusive due to the dense proton-proton dipolar coupling network. A novel MAS solid-state NMR pulse sequence is proposed to selectively recouple and measure interproton distances in protonated samples. The phase-modulated sequence combined with a judicious choice of transmitter frequency is used to measure quantitative 1H-1H distances on the order of 3 Å in l-histidine·HCl·H2O, despite the presence of other strongly coupled protons. This method provides a major boost to NMR crystallography approaches for structural determination of pharmaceutical molecules by directly measuring 1H-1H distances. The band-selective nature of the sequence also enables observation of selective 1H-1H correlations (e.g., HN-HN/HN-Hα/ΗΝ-ΗMethyl) in peptides and proteins, which should serve as useful restraints in structure determination.
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Affiliation(s)
- Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center , RIKEN , Yokohama , Kanagawa 230-0045 , Japan
| | - Sreejith Raran-Kurussi
- TIFR Centre for Interdisciplinary Sciences , Tata Institute of Fundamental Research Hyderabad , Sy. No. 36/P , Gopanpally, Ranga Reddy District, Hyderabad 500 107 , India
| | - Yusuke Nishiyama
- RIKEN-JEOL Collaboration Center , RIKEN , Yokohama , Kanagawa 230-0045 , Japan
- JEOL RESONANCE Inc. , Musashino, Akishima , Tokyo 196-8558 , Japan
| | - Vipin Agarwal
- TIFR Centre for Interdisciplinary Sciences , Tata Institute of Fundamental Research Hyderabad , Sy. No. 36/P , Gopanpally, Ranga Reddy District, Hyderabad 500 107 , India
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27
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Abstract
The combination of cross-polarization (CP) with flip-back (FB) pulse has enabled in NMR the enhancement of 13C sensitivity and the decrease of the recycling delay at both moderate and fast magic-angle spinning (MAS) frequencies. However, only continuous-wave (CW) decoupling is presently compatible with FB-pulse (FB-CW), and depending on the CW radio-frequency (rf) field, either an insignificant sensitivity gain or an acquisition time-dependent gain and a low 13C resolution are obtained. In this study, we propose a new FB-pulse method in which radio frequency-driven recoupling (RFDR) is used as the 1H-13C decoupling scheme to overcome these drawbacks. The performances of FB-RFDR in terms of decoupling efficiency and sensitivity gain are tested on both natural abundance (NA) and uniformly 13C-15N labeled l-histidine·HCl·H2O (Hist) samples at a MAS frequency of νR = 70 kHz. The results show the superiority of RFDR over the CW decoupling with respect to these criteria. Importantly, they reveal that the sensitivity gain offered by FB-RFDR is nearly independent of the decoupling/acquisition duration. The application of FB-RFDR on NA-Hist and sucrose yields a sensitivity gain between 60 and 100% compared to conventional FB-CW and CPMAS-SPINAL experiments. Moreover, we compare the 13C sensitivities of NA-Hist obtained by our 1D FB-RFDR method and 2D 1H-{13C} double-CP acquisition. Both methods provide similar 13C sensitivity and are complementary. Indeed, the 2D method has the advantage of also providing the 1H-13C spatial proximities, but its sensitivity for quaternary carbons is limited; whereas our 1D FB-RFDR method is more independent of the type of carbon, and can provide a 13C 1D spectrum in a shorter experimental time. We also test the feasibility of FB-RFDR at a moderate frequency of νR = 20 kHz, but the experimental results demonstrate a poor resolution as well as a negligible sensitivity gain.
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Affiliation(s)
- Nghia Tuan Duong
- RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
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28
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Duong NT, Kuprov I, Nishiyama Y. Indirect detection of 10B (I = 3) overtone NMR at very fast magic angle spinning. J Magn Reson 2018; 291:27-31. [PMID: 29677601 DOI: 10.1016/j.jmr.2018.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/05/2018] [Accepted: 04/09/2018] [Indexed: 06/08/2023]
Abstract
The application of overtone nuclear magnetic resonance (OT NMR) to symmetric spin transitions of integer quadrupolar nuclei is of considerable interest since this transition is immune to the first-order quadrupolar interaction, thus resulting in narrow NMR lines. Owing to its roles in nature and its high natural abundance, 14N (I = 1) OT NMR has been explored, in which the indirect and/or direct acquisitions of 14N OT were experimentally demonstrated. However, other than 14N nucleus, no OT NMR observation of other integer quadrupolar nuclei has been reported in the literature. In this work, we extend the application of OT NMR to another integer quadrupolar nucleus, namely 10B (I = 3). However, this is not straightforward owing to the unfavorable characteristics of 10B isotope. Here, for the first time, we present the selective acquisition of 10B central (-1 ↔ +1) OT NMR via detection of 1H nuclei on perborate monohydrate sample. Numerical calculations are in a good agreement with the experimental results. Both show that the optimal sensitivity is achieved when the carrier frequency is applied at the second OT spinning sideband, i.e. an offset of twice of the spinning frequency from the center band.
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Affiliation(s)
- Nghia Tuan Duong
- RIKEN CLST-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Ilya Kuprov
- School of Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Yusuke Nishiyama
- RIKEN CLST-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
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Zhang G, Tsujimoto M, Packwood D, Duong NT, Nishiyama Y, Kadota K, Kitagawa S, Horike S. Construction of a Hierarchical Architecture of Covalent Organic Frameworks via a Postsynthetic Approach. J Am Chem Soc 2018; 140:2602-2609. [DOI: 10.1021/jacs.7b12350] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Nghia Tuan Duong
- RIKEN CLST-JEOL Collaboration Center, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Nishiyama
- RIKEN CLST-JEOL Collaboration Center, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
- JEOL RESONANCE Inc., 3-1-2
Musashino, Akishima, Tokyo 196-8558, Japan
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30
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Duong NT, Yamato M, Nakano M, Kume S, Tamura Y, Kataoka Y, Wong A, Nishiyama Y. Capillary-Inserted Rotor Design for HRµMASNMR-Based Metabolomics on Mass-Limited Neurospheres. Molecules 2017; 22:E1289. [PMID: 28771206 PMCID: PMC6152061 DOI: 10.3390/molecules22081289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 07/30/2017] [Indexed: 11/17/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique and has been widely used in metabolomics. However, the intrinsic low sensitivity of NMR prevents its applications to systems with limited sample availabilities. In this study, a new experimental approach is presented to analyze mass-scarce samples in limited volumes of less than 300 nL with simple handling. The sample is loaded into the glass capillary, and this capillary is then inserted into a Kel-F rotor. The experimental performance of the capillary-inserted rotor (capillary-insert) is investigated on an isotropic solution of sucrose by the use of a high-resolution micro-sized magic angle spinning (HRµMAS) probe. The acquired NMR signal's sensitivity to a given sample amount is comparable or even higher in comparison to that recorded by the standard solution NMR probe. More importantly, this capillary-insert coupled with the HRµMAS probe allows in-depth studies of heterogeneous samples as the MAS removes the line broadening caused by the heterogeneity. The NMR analyses of mass-limited cultured neurospheres have been demonstrated, resulting in high quality spectra where numerous metabolites are unambiguously identified.
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Affiliation(s)
- Nghia Tuan Duong
- Advanced Solid-State NMR Unit, RIKEN CLST-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan.
| | - Masanori Yamato
- Multi-Modal Microstructure Analysis Unit, RIKEN CLST-JEOL Collaboration Center, RIKEN, Kobe, Hyogo 650-0047, Japan.
- Cellular Function Imaging Team, RIKEN Center for Life Science Technologies, Kobe, Hyogo 650-0047, Japan.
| | - Masayuki Nakano
- Cellular Function Imaging Team, RIKEN Center for Life Science Technologies, Kobe, Hyogo 650-0047, Japan.
- Department of Physiology, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka 545-8585, Japan.
| | - Satoshi Kume
- Multi-Modal Microstructure Analysis Unit, RIKEN CLST-JEOL Collaboration Center, RIKEN, Kobe, Hyogo 650-0047, Japan.
- Cellular Function Imaging Team, RIKEN Center for Life Science Technologies, Kobe, Hyogo 650-0047, Japan.
| | - Yasuhisa Tamura
- Multi-Modal Microstructure Analysis Unit, RIKEN CLST-JEOL Collaboration Center, RIKEN, Kobe, Hyogo 650-0047, Japan.
- Cellular Function Imaging Team, RIKEN Center for Life Science Technologies, Kobe, Hyogo 650-0047, Japan.
| | - Yosky Kataoka
- Multi-Modal Microstructure Analysis Unit, RIKEN CLST-JEOL Collaboration Center, RIKEN, Kobe, Hyogo 650-0047, Japan.
- Cellular Function Imaging Team, RIKEN Center for Life Science Technologies, Kobe, Hyogo 650-0047, Japan.
- Department of Physiology, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka 545-8585, Japan.
| | - Alan Wong
- NIMBE, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | - Yusuke Nishiyama
- Advanced Solid-State NMR Unit, RIKEN CLST-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan.
- Engineering Division, JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
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31
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Duong NT, Nishiyama Y. Satellite and central transitions selective 1H/{ 27Al} D-HMQC experiments at very fast MAS for quadrupolar couplings determination. Solid State Nucl Magn Reson 2017; 84:83-88. [PMID: 28089491 DOI: 10.1016/j.ssnmr.2016.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/20/2016] [Accepted: 12/29/2016] [Indexed: 06/06/2023]
Abstract
Recent study has demonstrated the application of the proton-detected heteronuclear multi-quantum coherence (HMQC) at ultrafast Magic Angle Spinning (MAS) to probe quadrupolar nuclei including 14N and 35Cl. In addition, for half-integer quadrupolar nucleus like 35Cl, the quadrupolar product can be calculated based on the shift difference between the center band of satellite transition (ST) and the central transition (CT) peaks. The applicability of this technique is further investigated on spin I=5/2, namely 27Al nucleus, and kaolin is chosen as the testing sample. However this study is not straightforward owing to a spin quantum number I=5/2 of 27Al nucleus and a small quadrupolar coupling of kaolin. Furthermore, very fast MAS, which is mandatory for proton-detected experiment to suppress 1H-1H homonuclear dipolar interactions, introduces additional complexities. It induces the partial overlap of CT and the center band of inner ST (ST1) resonance in addition to the insufficiency of CT-selective excitation by soft-pulse irradiation. In the current work, we employ the constant-time D-HMQC experiment, in which the duration between two recoupling blocks is fixed to a constant value and the arbitrary t1 increment can be used within this duration. This constant-time D-HMQC enables the precise determination of CT and ST resonance shifts through CT- and ST-selective observations by the indirect spectral width (i) with asynchronized sampling to the top of rotational-echoes for STs and (ii) three times larger than the spinning frequency, respectively. We also numerically and experimentally develop a satellite-selective excitation technique, in which the radio frequency field is applied to the first spinning sideband of ST1 resonance. The satellite-selective 1D single pulse and 2D conventional D-HMQC experiments are demonstrated. The quadrupolar product of 27Al nucleus extracted from the resulting spectra is in good agreement with the literature.
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Affiliation(s)
- Nghia Tuan Duong
- RIKEN CLST-JEOL collaboration center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Nishiyama
- RIKEN CLST-JEOL collaboration center, RIKEN, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
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Zhang R, Duong NT, Nishiyama Y, Ramamoorthy A. 3D Double-Quantum/Double-Quantum Exchange Spectroscopy of Protons under 100 kHz Magic Angle Spinning. J Phys Chem B 2017; 121:5944-5952. [DOI: 10.1021/acs.jpcb.7b03480] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Rongchun Zhang
- Biophysics
and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Nghia Tuan Duong
- RIKEN
CLST-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Nishiyama
- RIKEN
CLST-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
- JEOL Resonance Inc., Musashino, Akishima, Tokyo 196-8558, Japan
| | - Ayyalusamy Ramamoorthy
- Biophysics
and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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Lee D, Monin G, Duong NT, Lopez IZ, Bardet M, Mareau V, Gonon L, De Paëpe G. Untangling the Condensation Network of Organosiloxanes on Nanoparticles using 2D 29Si–29Si Solid-State NMR Enhanced by Dynamic Nuclear Polarization. J Am Chem Soc 2014; 136:13781-8. [DOI: 10.1021/ja506688m] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Daniel Lee
- Univ. Grenoble Alpes, INAC, F-38000 Grenoble, France
- CEA, INAC, SCIB, F-38000 Grenoble, France
| | - Guillaume Monin
- Univ. Grenoble Alpes, INAC, F-38000 Grenoble, France
- CEA, INAC, SPRAM, F-38000 Grenoble, France
- CNRS, SPRAM, F-38000 Grenoble, France
| | - Nghia Tuan Duong
- Univ. Grenoble Alpes, INAC, F-38000 Grenoble, France
- CEA, INAC, SCIB, F-38000 Grenoble, France
| | - Isabel Zamanillo Lopez
- Univ. Grenoble Alpes, INAC, F-38000 Grenoble, France
- CEA, INAC, SPRAM, F-38000 Grenoble, France
- CNRS, SPRAM, F-38000 Grenoble, France
| | - Michel Bardet
- Univ. Grenoble Alpes, INAC, F-38000 Grenoble, France
- CEA, INAC, SCIB, F-38000 Grenoble, France
| | - Vincent Mareau
- Univ. Grenoble Alpes, INAC, F-38000 Grenoble, France
- CEA, INAC, SPRAM, F-38000 Grenoble, France
- CNRS, SPRAM, F-38000 Grenoble, France
| | - Laurent Gonon
- Univ. Grenoble Alpes, INAC, F-38000 Grenoble, France
- CEA, INAC, SPRAM, F-38000 Grenoble, France
- CNRS, SPRAM, F-38000 Grenoble, France
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, INAC, F-38000 Grenoble, France
- CEA, INAC, SCIB, F-38000 Grenoble, France
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Mancy A, Antignac M, Minoletti C, Dijols S, Mouries V, Duong NT, Battioni P, Dansette PM, Mansuy D. Diclofenac and its derivatives as tools for studying human cytochromes P450 active sites: particular efficiency and regioselectivity of P450 2Cs. Biochemistry 1999; 38:14264-70. [PMID: 10572000 DOI: 10.1021/bi991195u] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A comparison of the oxidations of diclofenac with microsomes of yeasts expressing various human liver cytochromes P450 showed that P450 2C9 regioselectively led to 4'-hydroxy diclofenac (4'-OHD) whereas P450 3A4 only led to 5-hydroxy diclofenac (5-OHD). P450 2C19, 2C18, and 2C8 led to the simultaneous formation of 4'-OHD and 5-OHD (respective molar ratios of 1.3, 0.37, and 0.17), and P450 1A1, 1A2, 2D6, and 2E1 failed to give any detectable hydroxylated metabolite under identical conditions. P450 2C9 was found to be much more efficient for diclofenac hydroxylation than all the other P450s tested (k(cat)/K(M) of 1.6 min(-1) microM(-1) instead of 0.025 for the second more active P450), mainly because of markedly lower K(M) values (15 +/- 8 instead of values between 170 and 630 microM). Oxidation of diclofenac with chemical model systems of cytochrome P450 based on iron porphyrin catalysts exclusively led to the quinone imine derived from two-electron oxidation of 5-OHD, in an almost quantitative yield. Two derivatives of diclofenac lacking its COO(-) function were then synthesized; their oxidation by recombinant human P450 2Cs always led to a major product coming from their 5-hydroxylation. Substrate 2, which derives from reduction of the COO(-) function of diclofenac to the CH(2)OH function, was studied in more detail. All the P450s tested (1A1, 1A2, 2C8, 2C9, 2C18, 2C19, 2D6, and 3A4) almost exclusively led to its 5-hydroxylation. P450s of the 2C subfamily were found to be the most efficient catalysts for this reaction, with k(cat)/K(M) values between 0.2 and 1.6 min(-1) microM(-1). Oxidation of 2 with an iron porphyrin-based chemical model of cytochrome P450 also led to a product derived from the oxidation of 2 at position 5. These results show that oxidation of diclofenac and its derivative 2, either with chemical model systems of cytochrome P450 or with recombinant human P450s, generally occurs at position 5. This position, para to the NH group on the more electron-rich aromatic ring of diclofenac derivatives, is thus, as expected, the privileged site of reaction of electrophilic, oxidant species. The most spectacular exception to this chemoselective 5-oxidation of diclofenac derivatives was found for oxidation of diclofenac itself with P450 2C9 (and P450 2C19 and 2C18 to a lesser extent), which only led to 4'-OHD. A likely explanation for this result is a strict positioning of diclofenac in the P450 2C9 active site, via its COO(-) function, to completely orientate its hydroxylation toward position 4', which is not chemically preferred. P450 2C19, 2C18, and 2C8 would not lead to such a strict positioning as they give mixtures of 4'-OHD and 5-OHD. The above results show that diclofenac derivatives are interesting tools to compare the active site topologies of human P450 2Cs.
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Affiliation(s)
- A Mancy
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris V, Paris, France
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