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Ye K, Chin SY, Xi NL, Sharma B, Lu Y, Xue K. Characterizing the Behavior of Water Interacting with a Nano-Pore Material: A Structural Investigation in Native Environment Using Magnetic Resonance Approaches. Chemphyschem 2024; 25:e202400053. [PMID: 38706399 DOI: 10.1002/cphc.202400053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 04/28/2024] [Accepted: 05/03/2024] [Indexed: 05/07/2024]
Abstract
The study of fluid absorption, particularly that of water, into nanoporous materials has garnered increasing attention in the last decades across a broad range of disciplines. However, most investigation approaches to probe such behaviors are limited by characterization conditions and may lead to misinterpretations. In this study, a combined MRI and MAS NMR method was used to study a nanoporous silica glass to acquire information about its structural framework and interactions with confined water in a native humid environment. Specifically, MRI was used for a quantitative analysis of water extent. While MAS NMR techniques provided structural information of silicate materials, including interactive surface area and framework packing. Analysis of water spin-spin relaxation times (T2) suggested differences in water confinement within the characterized framework. Subsequent unsuccessful delivery of paramagnetic molecule into the pores enabled a quantitative assessment of the dimensions that "bottleneck" the pores. Finally, pore sizes were derived from the paramagnetic molecular size, density function theory (DFT) simulation and characterizations on standard samples. Our result matches with Brunauer-Emmett-Teller (BET) analysis that the pore size is less than 1.3 nm. The use of a paramagnetic probe for pore size determination introduces a new approach of characterization in the liquid phase, offering an alternative to the conventional BET analysis that uses gas molecule as probes.
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Affiliation(s)
- Kai Ye
- Center of High Field NMR Spectroscopy and Imaging, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639789, Singapore
| | - Sze Yuet Chin
- Center of High Field NMR Spectroscopy and Imaging, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Nicole Lin Xi
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639789, Singapore
| | - Bhargy Sharma
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639789, Singapore
| | - Yunpeng Lu
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639789, Singapore
| | - Kai Xue
- Center of High Field NMR Spectroscopy and Imaging, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
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2
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Wied JK, Mockenhaupt B, Schürmann U, Kienle L, Mangelsen S, Glänzer J, Celinski VR, Behrens M, Schmedt Auf der Günne J. Method for Surface Characterization Using Solid-State Nuclear Magnetic Resonance Spectroscopy Demonstrated on Nanocrystalline ZnO:Al. Anal Chem 2024; 96:11290-11298. [PMID: 38958037 DOI: 10.1021/acs.analchem.4c01170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Nanoscale zinc-oxide doped with aluminum ZnO:Al is studied by different techniques targeting surface changes induced by the conditions at which ZnO:Al is used as support material in the catalysis of methanol. While it is well established that a variety of 1H and 27Al resonances can be found by solid-state NMR for this material, it was not clear yet which signals are related to species located close to the surface of the material and which to species located in the bulk. To this end, a method is suggested that makes use of a paramagnetically impregnated material to suppress NMR signals close to the particle surface in the blind sphere around the paramagnetic metal atoms. It is shown that it is important to use conditions that guarantee a stable reference system relative to which it can be established whether the coating procedure is conserving the original structure or not. This method, called paramagnetically assisted surface peak assignment, helped to assign the 1H and 27Al NMR peaks to the bulk and the surface layer defined by the blind sphere of the paramagnetic atoms. The assignment results are further corroborated by the results from heteronuclear 27Al{1H} dipolar dephasing experiments, which indicate that the hydrogen atoms are preferentially located in the surface layer and not in the particle core.
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Affiliation(s)
- Jan Konrad Wied
- Faculty IV: School of Science and Technology, Department for Chemistry and Biology, Inorganic Materials Chemistry and Center of Micro- and Nanochemistry and Engineering (Cμ), University of Siegen, Adolf-Reichwein Straße 2, 57076 Siegen, Germany
| | - Benjamin Mockenhaupt
- Kiel University, Institute of Inorganic Chemistry, Max-Eyth-Straße 2, 24118 Kiel, Germany
| | - Ulrich Schürmann
- Department of Materials Science, Kiel University, Kaiserstraße 2, 24143 Kiel, Germany
| | - Lorenz Kienle
- Department of Materials Science, Kiel University, Kaiserstraße 2, 24143 Kiel, Germany
| | - Sebastian Mangelsen
- Kiel University, Institute of Inorganic Chemistry, Max-Eyth-Straße 2, 24118 Kiel, Germany
| | - Janin Glänzer
- Faculty IV: School of Science and Technology, Department for Chemistry and Biology, Inorganic Materials Chemistry and Center of Micro- and Nanochemistry and Engineering (Cμ), University of Siegen, Adolf-Reichwein Straße 2, 57076 Siegen, Germany
| | - Vinicius Ribeiro Celinski
- Faculty IV: School of Science and Technology, Department for Chemistry and Biology, Inorganic Materials Chemistry and Center of Micro- and Nanochemistry and Engineering (Cμ), University of Siegen, Adolf-Reichwein Straße 2, 57076 Siegen, Germany
| | - Malte Behrens
- Kiel University, Institute of Inorganic Chemistry, Max-Eyth-Straße 2, 24118 Kiel, Germany
| | - Jörn Schmedt Auf der Günne
- Faculty IV: School of Science and Technology, Department for Chemistry and Biology, Inorganic Materials Chemistry and Center of Micro- and Nanochemistry and Engineering (Cμ), University of Siegen, Adolf-Reichwein Straße 2, 57076 Siegen, Germany
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3
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Moroz IB, Feldman Y, Carmieli R, Liu X, Leskes M. Endogenous metal-ion dynamic nuclear polarization for NMR signal enhancement in metal organic frameworks. Chem Sci 2023; 15:336-348. [PMID: 38131097 PMCID: PMC10731914 DOI: 10.1039/d3sc03456a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 11/23/2023] [Indexed: 12/23/2023] Open
Abstract
Rational design of metal-organic framework (MOF)-based materials for catalysis, gas capture and storage, requires deep understanding of the host-guest interactions between the MOF and the adsorbed molecules. Solid-State NMR spectroscopy is an established tool for obtaining such structural information, however its low sensitivity limits its application. This limitation can be overcome with dynamic nuclear polarization (DNP) which is based on polarization transfer from unpaired electrons to the nuclei of interest and, as a result, enhancement of the NMR signal. Typically, DNP is achieved by impregnating or wetting the MOF material with a solution of nitroxide biradicals, which prevents or interferes with the study of host-guest interactions. Here we demonstrate how Gd(iii) ions doped into the MOF structure, LaBTB (BTB = 4,4',4''-benzene-1,3,5-triyl-trisbenzoate), can be employed as an efficient polarization agent, yielding up to 30-fold 13C signal enhancement for the MOF linkers, while leaving the pores empty for potential guests. Furthermore, we demonstrate that ethylene glycol, loaded into the MOF as a guest, can also be polarized using our approach. We identify specific challenges in DNP studies of MOFs, associated with residual oxygen trapped within the MOF pores and the dynamics of the framework and its guests, even at cryogenic temperatures. To address these, we describe optimal conditions for carrying out and maximizing the enhancement achieved in DNP-NMR experiments. The approach presented here can be expanded to other porous materials which are currently the state-of-the-art in energy and sustainability research.
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Affiliation(s)
- Ilia B Moroz
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science Rehovot 76100 Israel
| | - Yishay Feldman
- Department of Chemical Research Support, Weizmann Institute of Science Rehovot 76100 Israel
| | - Raanan Carmieli
- Department of Chemical Research Support, Weizmann Institute of Science Rehovot 76100 Israel
| | - Xinyu Liu
- Yusuf Hamied Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Michal Leskes
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science Rehovot 76100 Israel
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Radhakrishnan S, Smet S, Chandran CV, Sree SP, Duerinckx K, Vanbutsele G, Martens JA, Breynaert E. Prediction of Cu Zeolite NH 3-SCR Activity from Variable Temperature 1H NMR Spectroscopy. Molecules 2023; 28:6456. [PMID: 37764230 PMCID: PMC10537069 DOI: 10.3390/molecules28186456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/28/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Selective catalytic reduction (SCR) of NOx by ammonia is one of the dominant pollution abatement technologies for near-zero NOx emission diesel engines. A crucial step in the reduction of NOx to N2 with Cu zeolite NH3-SCR catalysts is the generation of a multi-electron donating active site, implying the permanent or transient dimerization of Cu ions. Cu atom mobility has been implicated by computational chemistry as a key factor in this process. This report demonstrates how variable temperature 1H NMR reveals the Cu induced generation of sharp 1H resonances associated with a low concentration of sites on the zeolite. The onset temperature of the appearance of these signals was found to strongly correlate with the NH3-SCR activity and was observed for a range of catalysts covering multiple frameworks (CHA, AEI, AFX, ERI, ERI-CHA, ERI-OFF, *BEA), with different Si/Al ratios and different Cu contents. The results point towards universal applicability of variable temperature NMR to predict the activity of a Cu-zeolite SCR catalyst. The unique relationship of a spectroscopic feature with catalytic behavior for zeolites with different structures and chemical compositions is exceptional in heterogeneous catalysis.
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Affiliation(s)
- Sambhu Radhakrishnan
- Centre for Surface Chemistry and Catalysis—Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR/X-ray Platform for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Sam Smet
- Centre for Surface Chemistry and Catalysis—Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - C. Vinod Chandran
- Centre for Surface Chemistry and Catalysis—Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR/X-ray Platform for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Sreeprasanth Pulinthanathu Sree
- Centre for Surface Chemistry and Catalysis—Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Karel Duerinckx
- Centre for Surface Chemistry and Catalysis—Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR/X-ray Platform for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Gina Vanbutsele
- Centre for Surface Chemistry and Catalysis—Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Johan A. Martens
- Centre for Surface Chemistry and Catalysis—Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR/X-ray Platform for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Eric Breynaert
- Centre for Surface Chemistry and Catalysis—Characterization and Application Team (COK-KAT), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR/X-ray Platform for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
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5
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6
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Jardón-Álvarez D, Malka T, van Tol J, Feldman Y, Carmieli R, Leskes M. Monitoring electron spin fluctuations with paramagnetic relaxation enhancement. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 336:107143. [PMID: 35085928 DOI: 10.1016/j.jmr.2022.107143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/30/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
The magnetic interactions between the spin of an unpaired electron and the surrounding nuclear spins can be exploited to gain structural information, to reduce nuclear relaxation times as well as to create nuclear hyperpolarization via dynamic nuclear polarization (DNP). A central aspect that determines how these interactions manifest from the point of view of NMR is the timescale of the fluctuations of the magnetic moment of the electron spins. These fluctuations, however, are elusive, particularly when electron relaxation times are short or interactions among electronic spins are strong. Here we map the fluctuations by analyzing the ratio between longitudinal and transverse nuclear relaxation times T1/T2, a quantity which depends uniquely on the rate of the electron fluctuations and the Larmor frequency of the involved nuclei. This analysis enables rationalizing the evolution of NMR lineshapes, signal quenching as well as DNP enhancements as a function of the concentration of the paramagnetic species and the temperature, demonstrated here for LiMg1-xMnxPO4 and Fe(III) doped Li4Ti5O12, respectively. For the latter, we observe a linear dependence of the DNP enhancement and the electron relaxation time within a temperature range between 100 and 300 K.
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Affiliation(s)
- Daniel Jardón-Álvarez
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tahel Malka
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Johan van Tol
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, FL 32310, United States
| | - Yishay Feldman
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Raanan Carmieli
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michal Leskes
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel.
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7
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Zehnder J, Cadalbert R, Yulikov M, Künze G, Wiegand T. Paramagnetic spin labeling of a bacterial DnaB helicase for solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 332:107075. [PMID: 34597956 DOI: 10.1016/j.jmr.2021.107075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 06/13/2023]
Abstract
Labeling of biomolecules with a paramagnetic probe for nuclear magnetic resonance (NMR) spectroscopy enables determining long-range distance restraints, which are otherwise not accessible by classically used dipolar coupling-based NMR approaches. Distance restraints derived from paramagnetic relaxation enhancements (PREs) can facilitate the structure determination of large proteins and protein complexes. We herein present the site-directed labeling of the large oligomeric bacterial DnaB helicase from Helicobacter pylori with cysteine-reactive maleimide tags carrying either a nitroxide radical or a lanthanide ion. The success of the labeling reaction was followed by quantitative continuous-wave electron paramagnetic resonance (EPR) experiments performed on the nitroxide-labeled protein. PREs were extracted site-specifically from 2D and 3D solid-state NMR spectra. A good agreement with predicted PRE values, derived by computational modeling of nitroxide and Gd3+ tags in the low-resolution DnaB crystal structure, was found. Comparison of experimental PREs and model-predicted spin label-nucleus distances indicated that the size of the "blind sphere" around the paramagnetic center, in which NMR resonances are not detected, is slightly larger for Gd3+ (∼14 Å) than for nitroxide (∼11 Å) in 13C-detected 2D spectra of DnaB. We also present Gd3+-Gd3+ dipolar electron-electron resonance EPR experiments on DnaB supporting the conclusion that DnaB was present as a hexameric assembly.
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Affiliation(s)
| | | | - Maxim Yulikov
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Georg Künze
- Institute for Drug Discovery, Medical School, Leipzig University, 04103 Leipzig, Germany.
| | - Thomas Wiegand
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland; Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany; Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
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8
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Cohen D, Mashiach R, Houben L, Galisova A, Addadi Y, Kain D, Lubart A, Blinder P, Allouche-Arnon H, Bar-Shir A. Glyconanofluorides as Immunotracers with a Tunable Core Composition for Sensitive Hotspot Magnetic Resonance Imaging of Inflammatory Activity. ACS NANO 2021; 15:7563-7574. [PMID: 33872494 PMCID: PMC8155386 DOI: 10.1021/acsnano.1c01040] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
Nature-inspired nanosized formulations based on an imageable, small-sized inorganic core scaffold, on which biomolecules are assembled to form nanobiomimetics, hold great promise for both early diagnostics and developed therapeutics. Nevertheless, the fabrication of nanobiomimetics that allow noninvasive background-free mapping of pathological events with improved sensitivity, enhanced specificity, and multiplexed capabilities remains a major challenge. Here, we introduce paramagnetic glyconanofluorides as small-sized (<10 nm) glycomimetics for immunotargeting and sensitive noninvasive in vivo19F magnetic resonance imaging (MRI) mapping of inflammation. A very short T1 relaxation time (70 ms) of the fluorides was achieved by doping the nanofluorides' solid crystal core with paramagnetic Sm3+, resulting in a significant 8-fold enhancement in their 19F MRI sensitivity, allowing faster acquisition and improved detectability levels. The fabricated nanosized glycomimetics exhibit significantly enhanced uptake within activated immune cells, providing background-free in vivo mapping of inflammatory activity, demonstrated in both locally induced inflammation and clinically related neuropathology animal models. Fabricating two types of nanofluorides, each with a distinct chemical shift, allowed us to exploit the color-like features of 19F MRI to map, in real time, immune specificity and preferred targetability of the paramagnetic glyconanofluorides, demonstrating the approach's potential extension to noninvasive multitarget imaging scenarios that are not yet applicable for nanobiomimetics based on other nanocrystal cores.
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Affiliation(s)
- Dana Cohen
- Department
of Organic Chemistry, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - Reut Mashiach
- Department
of Organic Chemistry, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - Lothar Houben
- Department
of Chemical Research Support, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - Andrea Galisova
- Department
of Organic Chemistry, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - Yoseph Addadi
- Life
Sciences Core Facilities, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - David Kain
- Neurobiology,
Biochemistry and Biophysics School, George S. Wise Faculty of Life
Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Alisa Lubart
- Neurobiology,
Biochemistry and Biophysics School, George S. Wise Faculty of Life
Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Pablo Blinder
- Neurobiology,
Biochemistry and Biophysics School, George S. Wise Faculty of Life
Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hyla Allouche-Arnon
- Department
of Organic Chemistry, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - Amnon Bar-Shir
- Department
of Organic Chemistry, Weizmann Institute
of Science, Rehovot 7610001, Israel
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9
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Mashiach R, Cohen D, Avram L, Harris T, Pinkas I, Houben L, Allouche-Arnon H, Bar-Shir A. Inducing Defects in 19F-Nanocrystals Provides Paramagnetic-free Relaxation Enhancement for Improved In Vivo Hotspot MRI. NANO LETTERS 2020; 20:7207-7212. [PMID: 32897716 PMCID: PMC7564093 DOI: 10.1021/acs.nanolett.0c02549] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Paramagnetic relaxation enhancement (PRE) is the current strategy of choice for enhancing magnetic resonance imaging (MRI) contrast and for accelerating MRI acquisition schemes. Yet, debates regarding lanthanides' biocompatibility and PRE-effect on MRI signal quantification have raised the need for alternative strategies for relaxation enhancement. Herein, we show an approach for shortening the spin-lattice relaxation time (T1) of fluoride-based nanocrystals (NCs) that are used for in vivo 19F-MRI, by inducing crystal defects in their solid-crystal core. By utilizing a phosphate-based rather than a carboxylate-based capping ligand for the synthesis of CaF2 NCs, we were able to induce grain boundary defects in the NC lattice. The obtained defects led to a 10-fold shorter T1 of the NCs' fluorides. Such paramagnetic-free relaxation enhancement of CaF2 NCs, gained without affecting either their size or their colloidal characteristics, improved 4-fold the obtained 19F-MRI signal-to-noise ratio, allowing their use, in vivo, with enhanced hotspot MRI sensitivity.
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Affiliation(s)
- Reut Mashiach
- Department
of Organic Chemistry, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Dana Cohen
- Department
of Organic Chemistry, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Liat Avram
- Department
of Organic Chemistry, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Talia Harris
- Department
of Organic Chemistry, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Iddo Pinkas
- Department
of Organic Chemistry, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Lothar Houben
- Department
of Organic Chemistry, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Hyla Allouche-Arnon
- Department
of Organic Chemistry, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Amnon Bar-Shir
- Department
of Organic Chemistry, Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 7610001, Israel
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10
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Jardón-Álvarez D, Reuveni G, Harchol A, Leskes M. Enabling Natural Abundance 17O Solid-State NMR by Direct Polarization from Paramagnetic Metal Ions. J Phys Chem Lett 2020; 11:5439-5445. [PMID: 32551646 PMCID: PMC7370305 DOI: 10.1021/acs.jpclett.0c01527] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 06/17/2020] [Indexed: 05/18/2023]
Abstract
Dynamic nuclear polarization (DNP) significantly enhances the sensitivity of nuclear magnetic resonance (NMR), increasing its applications and the quality of NMR spectroscopy as a characterization tool for materials. Efficient spin diffusion among the nuclear spins is considered to be essential for spreading the hyperpolarization throughout the sample, enabling large DNP enhancements. This scenario mostly limits the polarization enhancement of low-sensitivity nuclei in inorganic materials to the surface sites when the polarization source is an exogenous radical. In metal-ion-based DNP, the polarization agents are distributed in the bulk sample and act as a source of both relaxation and polarization enhancement. We have found that as long as the polarization agent is the main source of relaxation, the enhancement does not depend on the distance between the nucleus and dopant. As a consequence, the requirement of efficient spin diffusion is lifted, and the entire sample can be directly polarized. We exploit this finding to measure high-quality NMR spectra of 17O in the electrode material Li4Ti5O12 doped with Fe(III) despite its low abundance and long relaxation time.
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11
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Suta M, Antić Ž, Ðorđević V, Kuzman S, Dramićanin MD, Meijerink A. Making Nd 3+ a Sensitive Luminescent Thermometer for Physiological Temperatures-An Account of Pitfalls in Boltzmann Thermometry. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E543. [PMID: 32197319 PMCID: PMC7153599 DOI: 10.3390/nano10030543] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/12/2020] [Accepted: 03/13/2020] [Indexed: 12/25/2022]
Abstract
Ratiometric luminescence thermometry employing luminescence within the biological transparency windows provides high potential for biothermal imaging. Nd3+ is a promising candidate for that purpose due to its intense radiative transitions within biological windows (BWs) I and II and the simultaneous efficient excitability within BW I. This makes Nd3+ almost unique among all lanthanides. Typically, emission from the two 4F3/2 crystal field levels is used for thermometry but the small ~100 cm-1 energy separation limits the sensitivity. A higher sensitivity for physiological temperatures is possible using the luminescence intensity ratio (LIR) of the emissive transitions from the 4F5/2 and 4F3/2 excited spin-orbit levels. Herein, we demonstrate and discuss various pitfalls that can occur in Boltzmann thermometry if this particular LIR is used for physiological temperature sensing. Both microcrystalline, dilute (0.1%) Nd3+-doped LaPO4 and LaPO4: x% Nd3+ (x = 2, 5, 10, 25, 100) nanocrystals serve as an illustrative example. Besides structural and optical characterization of those luminescent thermometers, the impact and consequences of the Nd3+ concentration on their luminescence and performance as Boltzmann-based thermometers are analyzed. For low Nd3+ concentrations, Boltzmann equilibrium starts just around 300 K. At higher Nd3+ concentrations, cross-relaxation processes enhance the decay rates of the 4F3/2 and 4F5/2 levels making the decay faster than the equilibration rates between the levels. It is shown that the onset of the useful temperature sensing range shifts to higher temperatures, even above ~ 450 K for Nd concentrations over 5%. A microscopic explanation for pitfalls in Boltzmann thermometry with Nd3+ is finally given and guidelines for the usability of this lanthanide ion in the field of physiological temperature sensing are elaborated. Insight in competition between thermal coupling through non-radiative transitions and population decay through cross-relaxation of the 4F5/2 and 4F3/2 spin-orbit levels of Nd3+ makes it possible to tailor the thermometric performance of Nd3+ to enable physiological temperature sensing.
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Affiliation(s)
- Markus Suta
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Department of Chemistry, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands;
| | - Željka Antić
- Vinča Institute of Nuclear Sciences, University of Belgrade, 11001 Belgrade, Serbia; (Ž.A.); (V.Ð.); (S.K.); (M.D.D.)
| | - Vesna Ðorđević
- Vinča Institute of Nuclear Sciences, University of Belgrade, 11001 Belgrade, Serbia; (Ž.A.); (V.Ð.); (S.K.); (M.D.D.)
| | - Sanja Kuzman
- Vinča Institute of Nuclear Sciences, University of Belgrade, 11001 Belgrade, Serbia; (Ž.A.); (V.Ð.); (S.K.); (M.D.D.)
| | - Miroslav D. Dramićanin
- Vinča Institute of Nuclear Sciences, University of Belgrade, 11001 Belgrade, Serbia; (Ž.A.); (V.Ð.); (S.K.); (M.D.D.)
| | - Andries Meijerink
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Department of Chemistry, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands;
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Li W, Smet PF, Martin LIDJ, Pritzel C, Schmedt Auf der Günne J. Doping homogeneity in co-doped materials investigated at different length scales. Phys Chem Chem Phys 2020; 22:818-825. [PMID: 31840726 DOI: 10.1039/c9cp05599a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Doping homogeneity is important for the properties of co-doped phosphors, as it can affect the energy transfer between sensitizer and activator ions. In a case study we apply different methods, that is scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDX) mapping, SEM combined with cathodoluminescence (CL) and solid-state nuclear magnetic resonance (NMR), to study the doping homogeneity of the host system monazite LaPO4 doped with two different lanthanide ions on different length scales. A new criterion for doping heterogeneity in co-doped systems is developed, which is based on the NMR visibility function, which for this purpose is extended to doping with two or more paramagnetic dopants. A deviation from this function is indicative of doping heterogeneity on the length-scale of the blind-spheres of the paramagnetic dopants. A discussion of the advantages and disadvantages of the different methods is presented. The combined approach allows to study doping homogeneity from the nm to the μm scale.
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Affiliation(s)
- Wenyu Li
- Inorganic Materials Chemistry, University of Siegen, Adolf-Reichwein-Str. 2, 57076 Siegen, Germany.
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Li W, Adlung M, Zhang Q, Wickleder C, Schmedt auf der Günne J. A Guide to Brighter Phosphors-Linking Luminescence Properties to Doping Homogeneity Probed by NMR. Chemphyschem 2019; 20:3245-3250. [PMID: 31589801 PMCID: PMC6916297 DOI: 10.1002/cphc.201900790] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/19/2019] [Indexed: 12/03/2022]
Abstract
Crystalline powders of Ln3+ doped LaPO4 (Ln=Nd, Gd, Dy, Ho, Er, Tm, Yb) have been synthesized to serve in a case study for linking doping homogeneity as determined by NMR to luminescent properties. Samples obtained via different synthesis methods act as examples of homo- and inhomogeneous doping. The sample quality was verified by X-ray diffraction. The homogeneously doped samples show improved luminescent properties in terms of brightness and lifetime which is consistent with the interpretation that, NMR visibility curves probe the distribution of paramagnetic dopants on a similar length scale as necessary for an efficient energy transfer in crystalline phosphors i. e. between sensitizers and activators, and to killer sites. Thus "NMR homogeneity" as observed by visibility curves may serve as a tool to optimize luminescent materials.
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Affiliation(s)
- Wenyu Li
- Department of Chemistry and Biology ChemistryUniversity of SiegenAdolf-Reichwein-Str. 257076SiegenGermany
| | - Matthias Adlung
- Department of Chemistry and Biology ChemistryUniversity of SiegenAdolf-Reichwein-Str. 257076SiegenGermany
| | - Qianyun Zhang
- Department of Chemistry and Biology ChemistryUniversity of SiegenAdolf-Reichwein-Str. 257076SiegenGermany
| | - Claudia Wickleder
- Department of Chemistry and Biology ChemistryUniversity of SiegenAdolf-Reichwein-Str. 257076SiegenGermany
| | - Jörn Schmedt auf der Günne
- Department of Chemistry and Biology ChemistryUniversity of SiegenAdolf-Reichwein-Str. 257076SiegenGermany
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Kocman V, Di Mauro GM, Veglia G, Ramamoorthy A. Use of paramagnetic systems to speed-up NMR data acquisition and for structural and dynamic studies. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 102:36-46. [PMID: 31325686 PMCID: PMC6698407 DOI: 10.1016/j.ssnmr.2019.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 05/05/2023]
Abstract
NMR spectroscopy is a powerful experimental technique to study biological systems at the atomic resolution. However, its intrinsic low sensitivity results in long acquisition times that in extreme cases lasts for days (or even weeks) often exceeding the lifetime of the sample under investigation. Different paramagnetic agents have been used in an effort to decrease the spin-lattice (T1) relaxation times of the studied nuclei, which are the main cause for long acquisition times necessary for signal averaging to enhance the signal-to-noise ratio of NMR spectra. Consequently, most of the experimental time is "wasted" in waiting for the magnetization to recover between successive scans. In this review, we discuss how to set up an optimal paramagnetic relaxation enhancement (PRE) system to effectively reduce the T1 relaxation times avoiding significant broadening of NMR signals. Additionally, we describe how PRE-agents can be used to provide structural and dynamic information and can even be used to follow the intermediates of chemical reactions and to speed-up data acquisition. We also describe the unique challenges and benefits associated with the application of PRE to solid-state NMR spectroscopy, explaining how the use of PREs is more complex for membrane mimetic systems as PREs can also be exploited to change the alignment of oriented membrane systems. Functionalization of membrane mimetics, such as bicelles, can provide a controlled region of paramagnetic effect that has the potential, together with the desired alignment, to provide crucial biologically relevant structural information. And finally, we discuss how paramagnetic metals can be utilized to further increase the dynamic nuclear polarization (DNP) effects and how to preserve the enhancements when dissolution DNP is implemented.
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Affiliation(s)
- Vojč Kocman
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA; Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, USA
| | | | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA; Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, USA.
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