Journal of Magnetic Resonance Open最新文献

{"title":"Paramagnetic relaxation: Direct and Raman relaxation of spin S=12","authors":"W.Th. Wenckebach","doi":"10.1016/j.jmro.2025.100193","DOIUrl":"10.1016/j.jmro.2025.100193","url":null,"abstract":"<div><div>Paramagnetic relaxation in solids is a vast subject, about as vast as the range of manifestations of electron spin in matter. It is a complex subject as well: it is the interface between paramagnetic centres – be it transition metal ions, radicals or defects – and quantized vibrations: phonons. So it requires an understanding of both these phonons and those paramagnetic centres. Moreover, contrary to the case of integer spin, for half-integer spin the coupling between electron spins and phonons is indirect. Two interactions are needed, the spin–orbit interaction between the spin and the orbits of the paramagnetic centre and the orbit–phonon interaction between the latter and the phonons.</div><div>The present article is an effort to navigate the theory of this extensive subject for spin <span><math><mrow><mi>S</mi><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></math></span> and aims to derive the main properties of the two most important mechanisms: direct and red Raman relaxation. It tries to do so from first principles, that is, it includes a generalized, but fundamental description of the vibrational states, the orbital and spin states on the one hand, and the orbit–phonon and spin–orbit interaction on the other. Based on these descriptions it derives the transition matrix elements responsible for paramagnetic relaxation, following the original approach of Van Vleck for paramagnetic centres with spin <span><math><mrow><mi>S</mi><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></math></span>, a relatively weak spin–orbit interaction and embedded in an insulating, diamagnetic solid. Subsequently phonon statistics are included to derive the paramagnetic relaxation rates. No effort is done to review the vast body of experimental work on the subject.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100193"},"PeriodicalIF":2.624,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introduction to average Hamiltonian theory. II. Advanced examples","authors":"Andreas Brinkmann","doi":"10.1016/j.jmro.2025.100191","DOIUrl":"10.1016/j.jmro.2025.100191","url":null,"abstract":"<div><div>Where the first part of our tutorial <em>Introduction to average Hamiltonian theory</em> (Brinkmann, 2016) introduced in detail the basic concepts and demonstrated the application to two composite radio-frequency (rf) pulses in nuclear magnetic resonance (NMR) spectroscopy, this second part will present in a comprehensive but educational manner two, more advanced examples for the application of average Hamiltonian theory in solid-state NMR spectroscopy, both to analyse and design rf pulse sequences: (i) The Rotational-Echo Double Resonance (REDOR) sequence, which recouples the heteronuclear dipolar coupling during sample rotation around an axis at the magic-angle of <span><math><mrow><mn>54</mn><mo>.</mo><mn>7</mn><msup><mrow><mn>4</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span> with respect to the external static magnetic field. We will gradually increase the complexity of applying average Hamiltonian theory by first considering ideal, infinitesimally short rf pulses. Next, we will examine finite pulses with an rf phase of zero, and finally, we will explore finite pulses with arbitrary rf phases. In the latter case, if a first order average Hamiltonian proportional to heteronuclear longitudinal two-spin order (<span><math><mrow><mn>2</mn><msub><mrow><mi>I</mi></mrow><mrow><mi>z</mi></mrow></msub><msub><mrow><mi>S</mi></mrow><mrow><mi>z</mi></mrow></msub></mrow></math></span>) is desired, solutions for the choice of rf phases include the XY and MLEV type schemes. (ii) The Lee–Goldburg homonuclear dipolar decoupling sequence under static samples conditions and its improved successors, Flip-Flop Lee–Goldburg (FFLG) and Frequency-Switched Lee–Goldburg (FSLG).</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100191"},"PeriodicalIF":2.624,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probing cation dynamics and phase transition in hybrid organic-inorganic perovskites by 13C solid-state NMR spectroscopy at very high resolution","authors":"Yue Dou ,&nbsp;Qing Wang ,&nbsp;Hengxing Ji ,&nbsp;Haiming Liu","doi":"10.1016/j.jmro.2025.100197","DOIUrl":"10.1016/j.jmro.2025.100197","url":null,"abstract":"<div><div>The spatial dynamics of cations have a significant impact on the photodynamic behavior of excited states in high-performance hybrid organic-inorganic perovskites. Multinuclear (¹H, ²H, and ¹⁴N) solid-state NMR (SSNMR) spectroscopy has traditionally been utilized to study the motion of methylammonium (MA) cations in methylammonium lead (II) halides MAPbX₃ (X = I, Br, Cl). NMR methods based on spin-lattice relaxation or quadrupolar line shape analysis over a limited temperature range demonstrate rapid MA reorientation, but the cation dynamics in a wider temperature range covering phase transition of all major crystallographic phases is lacking. Due to its low sensitivity, ¹³C NMR is rarely used to assess MA dynamics in these perovskites. Herein, we adopte variable-temperature (VT) ¹³C MAS NMR at very high resolution and dipolar-coupled transverse relaxation analysis as a new tool for dynamical characterization without isotopic enrichment, and systematically investigated MA dynamics in MAPbX₃ across phase transitions. This new approach enables retrieval of activation energy of MA reorientation and assessment of motion regimes. We propose a generalized “Camel model” that describes the common trend of cation dynamics for MAPbX₃, suggesting possible complicated reorientation modes. Furthermore, we discover the evolution of multiple MA sites in orthorhombic MAPbCl₃, consistent with X-ray crystallography, demonstrating its unique advantage in resolving and characterizing multi-cation dynamics. The VT ¹³C SSNMR effectively probes organic ion motions and phase transitions in hybrid perovskites, helpful for further elucidating the structure-property relationship in photovoltaic conversion mechanisms.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100197"},"PeriodicalIF":2.624,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of the surface relaxivity of soft sediment using particle size and shape","authors":"Nick J. Hol ,&nbsp;Ismail Myouri ,&nbsp;Claire Chassagne ,&nbsp;Leo Pel","doi":"10.1016/j.jmro.2025.100198","DOIUrl":"10.1016/j.jmro.2025.100198","url":null,"abstract":"<div><div>This study presents a method to determine surface relaxivity in soft sediments by combining one-dimensional Nuclear Magnetic Resonance (NMR) imaging with particle size and shape estimates. In order to determine the surface relaxivity up to now often methods like Mercury Intrusion Porosimetry or Brunauer–Emmett–Teller (BET) are used which where drying steps are involved which can alter material properties during analysis, particularly in highly deformable materials, making these techniques unreliable for soft soils. By combining NMR relaxometry and estimates of particle sizes and shapes of a soft soil, this new approach provides accurate, non-invasive surface relaxivity measurements. This method is demonstrated on kaolinite, glass beads, and natural soils, showing that this method supports detailed assessment of pore size distributions in soft sediments, benefiting geotechnical and environmental research where soil stability is critical.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"23 ","pages":"Article 100198"},"PeriodicalIF":2.624,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chiral recognition of some D and L-amino acids by microcrystalline cellulose assisted diffusion-ordered NMR spectroscopy","authors":"Bowen Han ,&nbsp;Jing He ,&nbsp;Shaohua Huang","doi":"10.1016/j.jmro.2025.100189","DOIUrl":"10.1016/j.jmro.2025.100189","url":null,"abstract":"<div><div>Chiral amino acids play an indispensable role in living organisms. Diffusion-ordered NMR spectroscopy is an effective NMR tool and a noninvasive analytical method for the analyses of mixture without the need for physical separation of the analytes. However, conventional diffusion-ordered NMR spectroscopy method usually fails to resolve the mixtures of chiral amino acids because of their same molecular masses, sizes, and shapes. Microcrystalline cellulose has been gradually gained more and more interest owing to its wide compatibility, surface area, excellent separation efficiency, non-toxicity, cost-effective, and mechanical stability in many fields. Herein we provide a fast, simple, specific and sensitive method to resolve some D and L-amino acids mixtures by using microcrystalline cellulose as a matrix. This work recognized some D and L- proteinogenic amino acid enantiomers with diffusion-ordered NMR for the first time.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100189"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A hybrid setup for rodent hyperpolarized metabolic imaging using a clinical magnetic resonance scanner","authors":"Ditte Bentsen Christensen ,&nbsp;Ingeborg Sæten Skre ,&nbsp;Jan Henrik Ardenkjær-Larsen ,&nbsp;Mor Mishkovsky ,&nbsp;Mathilde H Lerche","doi":"10.1016/j.jmro.2025.100190","DOIUrl":"10.1016/j.jmro.2025.100190","url":null,"abstract":"<div><div>Metabolic magnetic resonance spectroscopic imaging using hyperpolarized contrast agents offers a non-invasive approach to monitoring real-time in vivo energy metabolism. The technique involves hyperpolarizing a contrast agent in a polarizer, administering it to a living system, and then imaging its distribution and metabolites using a magnetic resonance scanner. Over the past two decades, the method has transitioned from in vitro studies to clinical research, with an increasing focus on clinical applications.</div><div>Here, we present a hybrid system that adapts a clinical magnetic resonance scanner for pre-clinical rodent experiments. The hybrid system includes (1) a customizable, 3D-printable animal cradle setup and (2) optimized imaging strategies, including coil configurations, metabolic contrast agent administration, and proton imaging acquisition. The system enables ¹³C dynamic imaging, which we illustrate with detection of hyperpolarized [1–¹³C]pyruvate and its metabolites in the mouse brain. We detail the experimental procedure, provide practical guidance, and showcase the capabilities of the system with example data from mouse brain imaging.</div><div>This hybrid setup bridges the gap between clinical and pre-clinical research, enabling iterative testing of equipment, imaging sequences, and hypotheses across phantoms, in vivo rodent models and clinical settings. By facilitating a smoother translation, both forward and reverse, between pre-clinical and clinical applications, this approach enhances the potential for advancing metabolic imaging research.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100190"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143353597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic electron and nuclear spin polarization in solution using porphyrin and tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivatives","authors":"Reiya Yabuki ,&nbsp;Koki Nishimura ,&nbsp;Yuta Sawada ,&nbsp;Masaaki Fuki ,&nbsp;Yasuhiro Kobori ,&nbsp;Nobuhiro Yanai","doi":"10.1016/j.jmro.2024.100181","DOIUrl":"10.1016/j.jmro.2024.100181","url":null,"abstract":"<div><div>Chemically induced dynamic electron polarization (CIDEP) generates radical electron spins with high polarization at room temperature by quenching the photo-excited state of chromophores, which is useful for microwave-free optical dynamic nuclear polarization (DNP) in solution. While nitroxyl (TEMPO) radicals are typically used for this purpose, we show that a tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivative shows greater electron spin polarization than TEMPO by CIDEP using porphyrin chromophores. This is attributed to the longer spin-lattice relaxation time of TTM radicals, with a contribution of efficient quenching of chromophore photo-excited state by energy transfer from the triplet state of porphyrins to the doublet state of the TTM radicals. The porphyrin-TTM pair shows a larger nuclear spin polarization under continuous laser excitation than the porphyrin-TEMPO pair because of the larger polarization and longer spin-lattice relaxation time of the TTM radical electron spins. This work demonstrates the first example of in-solution CIDEP and optically-driven DNP using TTM radicals, opening new opportunities in a wide range of biological and medical applications.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100181"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the impact of second-order 1H-17O Quadrupolar-Dipolar interaction on solid-state NMR spectroscopy","authors":"Yi Ji ,&nbsp;Kuizhi Chen ,&nbsp;Aijing Hao ,&nbsp;Guangjin Hou","doi":"10.1016/j.jmro.2024.100182","DOIUrl":"10.1016/j.jmro.2024.100182","url":null,"abstract":"<div><div>Recent advances in the ¹⁷O-enrichment techiques and high-resolution nuclear magnetic resonance (NMR) methods have opened new opportunities to utilize ¹⁷O NMR to disentangle the zeolitic structure−property relationship that has not been well resolved through traditional ¹H, ²⁷Al, and ²⁹Si NMR spectroscopy. Compared with one-dimensional ¹⁷O magic angle spinning (MAS) NMR experiments, ¹H-¹⁷O correlation spectrocopy has become a crucial method for revealing the structures and dynamics of reactive hydroxyl species in zeolites with higher resolution and precision. However, the introduction of ¹⁷O can induce changes in ¹H MAS NMR signals due to the second-order ¹H-¹⁷O quadrupolar-dipolar (2nd-QD) cross interaction, which has recently been revealed by us on H-ZSM-5 (H-MFI) zeolites with 10-membered-ring (MR) channels. Herein, we performed various ¹H-¹⁷O correlation experiments (¹H{¹⁷O}-<em>J</em>-heteronuclear multiple quantum coherence (HMQC), ¹H{¹⁷O}-<em>D</em>-HMQC, and ¹H→¹⁷O-<span><em>D</em></span>-RINEPT) on two other types of ¹⁷O-enriched zeolites, i.e., H-Mordenite (H-MOR) with 8-/12-MR channels and H-ZSM-35 (H-FER) with 8-/10-MR channels. Notably, unusual ¹H-¹⁷O correlation signals with tilted patterns and magnetic-field-dependent shifts were observed on both samples and all tested correlation experiments at high fields up to 18.8 T. These observations were further comprehensively explained by theoretical analysis of the ¹H-¹⁷O quadrupolar-dipolar interaction, thus demonstrating that the ¹H-¹⁷O 2nd-QD interaction generally affects the ¹H and ¹H-¹⁷O correlation MAS NMR spectra of the dehydrated ¹⁷O-enriched zeolites, irrespective of the framework types. Beyond zeolites, the non-ignorable 2nd-QD interaction on NMR spectroscopy can complicate NMR identification of ¹⁷O-labeled hydroxyls in many other inorganic materials and biomolecules. The analysis methods proposed in this study are expected to effectively address these challenges and provide clearer insights into such systems.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100182"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developing hyperpolarized metabolic contrast agents at high field dDNP for large animal research","authors":"Ditte B. Christensen ,&nbsp;Ingeborg S. Skre ,&nbsp;Jan Henrik Ardenkjær-Larsen,&nbsp;Magnus Karlsson,&nbsp;Mathilde H. Lerche","doi":"10.1016/j.jmro.2024.100184","DOIUrl":"10.1016/j.jmro.2024.100184","url":null,"abstract":"<div><div>Dissolution Dynamic Nuclear Polarization (dDNP) polarizers have achieved high field strengths and large sample volumes. These advancements necessitate new formulations of hyperpolarized metabolic contrast agents (HMCAs) to enable large animal studies. While several metabolic substrates have been investigated at lower field dDNP and tested as HMCAs in rodents, ¹³C-labeled pyruvate remains the most studied HMCA and is currently the only one actively used in clinical trials due to its favorable biological and physical properties. Effective human and large animal dDNP formulations require high molar substrate concentrations, low DNP sample viscosity for efficient dissolution, and adequate dilution of the DNP sample to minimize signal decay and maximize HMCA concentration.</div><div>We present substrate formulations optimized for high-field polarization and large-volume dissolution. Specifically, we validate the upscaling of [1–¹³C]pyruvate under high-field conditions and demonstrate that [1–¹³C]2-keto-isocaproate and [1,4–¹³C₂]fumarate, which have been proven successful in rodent studies, can be formulated to yield high polarization at suitable concentrations and volumes for large animal metabolic MR imaging.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100184"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperpolarized 129Xe for benchtop NMR: Inline instrumentation for automated yet flexible operation yielding high polarization","authors":"Wolfgang Kilian ,&nbsp;Samira Gulich ,&nbsp;Thomas Riemer ,&nbsp;Lorenz Mitschang","doi":"10.1016/j.jmro.2024.100179","DOIUrl":"10.1016/j.jmro.2024.100179","url":null,"abstract":"<div><div>The use of hyperpolarized media in combination with benchtop NMR spectrometers is currently extensively investigated to enable cost effective but highly sensitive applications. In this work, the instrumentation for the use of hyperpolarized ¹²⁹Xe gas on a commercial benchtop-NMR spectrometer in a fully controllable yet automated mode is presented. A continuous-flow ¹²⁹Xe polarizer is operated inline with the benchtop spectrometer. While the adjustment of the xenon gas partial pressure in the range of mbar to bar as well as the volume flow through the NMR sample is facilitated by the polarizer’s mass-flow controllers and two back-pressure regulators, respectively, the gas flow towards the NMR sample in situ in the benchtop magnet is time-controlled within the spectrometer’s RF pulse sequence programming. A calibration procedure for the gas flow control as well as thermally polarized xenon gas standards are introduced for quantification of the absolute ¹²⁹Xe polarization. In this way, the ¹²⁹Xe polarization achieved in the NMR measurement is determined in the 50% to 5% regime for very lean 1<!--> <!-->mbar to high 500<!--> <!-->mbar xenon partial pressure, respectively – in the optimum a more than 250,000-fold increase in comparison to thermal polarization. Such instrumentation may be implemented by combining any of the well-established continuous-flow ¹²⁹Xe polarizer with any of the commercial benchtop spectrometers, thus facilitating high-performance hyperpolarized ¹²⁹Xe benchtop NMR studies.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100179"},"PeriodicalIF":2.624,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}