Magnetic Resonance in Chemistry最新文献

{"title":"Synthesis and Application of a Hydrophobic Polyglutamate Bearing a Triphenylphosphine Group for the Orientation of Pharmaceutically Active Compounds and the Measurement of Residual Dipolar Couplings","authors":"Jan Rettig, Michael Gölz, Christina M. Thiele","doi":"10.1002/mrc.5522","DOIUrl":"10.1002/mrc.5522","url":null,"abstract":"<p>If dissolved in a suitable, helicogenic solvent like chloroform, the homopolypeptide poly-γ-benzyl-<span>l/d</span>-glutamate (PB(<span>L/D</span>)G) is known to adopt an α-helical conformation, stabilized by intramolecular hydrogen bonding [<span>1, 2</span>]. These helices exhibit a screw sense that depends on the centrochirality of the amino acid in the polymer backbone with the γ-esters of <span>l</span>-glutamic acid forming right-handed (<i>P</i>) helices and the γ-esters of <span>d</span>-glutamic acid forming left-handed (<i>M</i>) helices [<span>3, 4</span>]. This α-helical secondary structure leads to a rigid rod-like behavior causing shape anisotropy, which allows dissolved PB(L/D)G—and other polypeptides and polymer classes [<span>5, 6</span>]—to form lyotropic liquid crystalline (LLC) phases above a system-specific critical concentration in helicogenic solvents [<span>7-10</span>]. These LLC phases [<span>11-13</span>] have been studied as alignment media [<span>10, 14-25</span>]. The mesogens of LLC-based alignment media align relative to the external magnetic field [<span>11, 12</span>] and—if an analyte is added—can interact with this compound transferring this alignment partially onto the analyte [<span>26</span>]. This induces anisotropy in the tumbling and rotation of the analyte, making anisotropic NMR observables accessible for structure elucidation [<span>27</span>]. These anisotropic observables yield complementary global structural information to the established local isotropic observables, nuclear Overhauser effect (nOe) [<span>28-30</span>] or scalar coupling (<i>J</i>) [<span>31-33</span>]. The anisotropic NMR observables are the residual chemical shift anisotropy (RCSA) [<span>34-36</span>], residual quadrupolar couplings (RQCs) [<span>24, 37</span>], and residual dipolar couplings (RDCs) [<span>5, 27, 38, 39</span>], with this publication focusing on the latter.</p><p>Especially sought-after media are compatible with a wide range of analytes that allow the extraction of all possible one-bond carbon-hydrogen (<sup>1</sup><i>D</i><sub>CH</sub>) RDCs of a given compound and exhibit excellent spectral quality with line widths comparable to the isotropic state. In this work, we present the synthesis of the new polymers diphenylphosphine sulfide poly-γ-benzyl-<span>l</span>/<span>d</span>-glutamate (DPPS-PB(L/D)G), in which the benzyl ring in the sidechain of the previously mentioned PB(L/D)G is extended to a sulfur-protected triphenylphosphine unit (see Figure 1).</p><p>By expanding the benzyl ring to triphenylphosphine, we hope to retain the necessary α-helical conformation of PB(L/D)G in solution but alter the alignment properties compared with the parent polymer. The polyglutamate DPPS-PB(L/D)G (Figure 1, bottom left) presented herein is the first result of a hybrid synthesis strategy in which we aim to synthesize polymers that can act not only as an alignment medium but potentially as a polymeric ligand for asymmetr","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 5-6","pages":"406-416"},"PeriodicalIF":1.4,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5522","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143909560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Processing Methods on the Physical Properties of Aquafaba Powder: Time-Domain Nuclear Magnetic Resonance Analysis","authors":"Elif Gokcen Ates,&nbsp;Gokcem Tonyali Karsli,&nbsp;Ozcan Dilara Ozcan,&nbsp;Emin Burcin Ozvural,&nbsp;Mecit H. Oztop","doi":"10.1002/mrc.5521","DOIUrl":"10.1002/mrc.5521","url":null,"abstract":"<div>\u0000 \u0000 <p>Aquafaba, the water remaining after cooking chickpeas, has been a promising emulsifier and stabilizer in food products. Despite its potential, the variability in its composition and dry matter content poses challenges for its consistent use. This study aimed to enhance the dry matter content of aquafaba through different processing methods—microwave heating, microwave-infrared heating, and conventional boiling—and to evaluate how these methods affect the physical properties of the resulting powders. The experiment also explored the effect of overnight soaking of chickpeas on the dry matter yield. The powders produced were characterized using time-domain nuclear magnetic resonance (TD-NMR) to investigate their water absorption, hydration behavior, and emulsification properties. Results showed that microwave and microwave-infrared heating significantly increased the dry matter content compared to conventional boiling. Furthermore, overnight soaking of chickpeas led to a notable increase in dry matter yield across all processing methods. TD-NMR analysis revealed that microwave-infrared samples exhibited improved hydration rates and more stable emulsions over time compared to those processed with other methods. These findings suggest that alternative processing techniques, especially microwave-infrared heating, can improve the consistency and functionality of aquafaba as an ingredient in food products. By increasing the dry matter content and enhancing hydration properties, these methods may provide a more reliable plant-based emulsifier. This study contributes to the development of novel, sustainable approaches in food processing that can enhance the quality and performance of plant-based ingredients across various applications.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 5-6","pages":"394-405"},"PeriodicalIF":1.4,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143788432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complete 1H and 13C NMR Assignment of the ent-Labdane 2α-Hydroxyeperuic Acid Combining Conventional NMR Methods and HiFSA","authors":"Francisco Juárez-Carrillo,&nbsp;Hugo A. García-Gutiérrez,&nbsp;Mónica Luna-Vázquez,&nbsp;José Carlos Espinoza-Hicks,&nbsp;Judit A. Aviña-Verduzco,&nbsp;Ramón Guzmán-Mejía,&nbsp;Concepción Armenta-Salinas,&nbsp;Carlos M. Cerda-García-Rojas,&nbsp;Julio C. Ontiveros-Rodríguez","doi":"10.1002/mrc.5519","DOIUrl":"10.1002/mrc.5519","url":null,"abstract":"<div>\u0000 \u0000 <p>The complete assignment of ¹H and ¹³C spectra of the <i>ent-</i>labdane 2α-hydroxyeperuic acid (<b>3</b>) has been achieved through spin simulation constructed with experimental data obtained from conventional NMR experiments such as ¹H, ¹³C, HSQC, HMBC, COSY, NOESY, 1D-TOCSY, and <i>J-</i>resolved (<i>J</i>res) and data obtained from ¹H iterative full-spin analysis (HiFSA) in the prerelease version of Cosmic Truth (CT), a web-based software for spectral analysis. The combination of experimental and theoretical data is helpful in the complete NMR assignment of molecules where signal overlapping is complicated, as in most natural products.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 5-6","pages":"387-393"},"PeriodicalIF":1.4,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143605307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting the Structure of Cacospongionolide E: An Approach Based on Empirical Rules and NMR Calculations","authors":"Yuto Nishidono,&nbsp;Ken Tanaka","doi":"10.1002/mrc.5518","DOIUrl":"10.1002/mrc.5518","url":null,"abstract":"<div>\u0000 \u0000 <p>In the field of natural product chemistry, the structures of several marine natural products have been erroneously determined. Here, we revisited the originally proposed structure of cacospongionolide E (<b>1</b>) using empirical rules in ¹³C NMR chemical shift analysis and density functional theory (DFT)-based NMR chemical shift calculations. Cacospongionolide E (<b>1</b>) is a marine natural product isolated from the Tyrrhenian sponge <i>Fasciospongia cavernosa</i>. Its originally proposed structure was established as sesterterpenoid of the <i>trans</i>–<i>trans</i> (TT) type, which adopts the <i>trans</i>–<i>trans</i> configuration of the 5-CH₃/10-H–8-CH₃/9-CH₃ fragment. However, the present analysis based on empirical rules revealed that the reported ¹³C NMR chemical shifts of cacospongionolide E were more consistent with those of <i>cis</i>–<i>trans</i> (CT) type <b>2</b>, which adopts the <i>cis</i>–<i>trans</i> configuration of the 5-CH₃/10-H–8-CH₃/9-CH₃ fragment, than those of TT type <b>1</b>. Furthermore, DFT-based ¹³C NMR chemical shift calculations, followed by the DP4 analysis, revealed that the reported ¹³C NMR chemical shifts of cacospongionolide E were more consistent with the calculated chemical shifts of CT type <b>2</b> than those of TT type <b>1</b>. Thus, we propose the stereochemical revision of the structure of cacospongionolide E from the originally proposed structure <b>1</b> to our proposed structure <b>2</b>. The study findings show that the proposed approach based on empirical rules and DFT-based NMR chemical shift calculations can identify the incorrect structures of marine natural products and provide the candidate for the correct structures.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 5-6","pages":"380-386"},"PeriodicalIF":1.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143542479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantification of mRNA Using 31P NMR Spectroscopy and CRAFT","authors":"Gennady Khirich,&nbsp;Vanessa A. Noreika,&nbsp;Kaitlyn Doolittle Catlin,&nbsp;José G. Napolitano,&nbsp;David J. Russell,&nbsp;Oliver Birkholz,&nbsp;Jens Schumacher,&nbsp;Heinrich Haas,&nbsp;Ken Skidmore","doi":"10.1002/mrc.5516","DOIUrl":"10.1002/mrc.5516","url":null,"abstract":"<div>\u0000 \u0000 <p>Messenger RNA (mRNA) has emerged as a promising therapeutic modality in vaccine development due to its safety, efficacy, and rapid development potential. Reliable measurement and comparison of mRNA concentration in different chemical environments are crucial for research and manufacturing purposes. Conventionally, UV spectroscopy is used for quantification. However, variability in solution conditions, such as ionic strength, may influence the measurement of the UV absorbance at 260 nm, <i>A</i>₂₆₀. This therefore necessitates accurate calibration of the extinction coefficient, <i>ε</i>, at a given set of solution conditions to the concentration of mRNA, as measured by an orthogonal and quantitative method. To that end, we utilized quantitative ³¹P NMR spectroscopy. We outline a general quantitative treatment of mRNA samples that may contain multiple polyadenylated mRNA sequences and show that the bias introduced by the method's assumptions into the measured mRNA concentrations is expected to be ≤ 4%. We also identified the limitations and subjectivities of accurate integration-based measurement of broad mRNA resonances in the frequency domain through a mini round-robin study. Quantification of broad mRNA signals using CRAFT in the time domain is shown to be superior to integration, as any subjectivity potentially introduced by the operator during spectral processing is obviated. This enables the use of ³¹P qNMR to accurately quantify total mRNA content and thus accurately calibrate mRNA extinction coefficients.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 5-6","pages":"370-379"},"PeriodicalIF":1.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solid-State NMR-Assisted Dynamic Characterization of two Isostructural Solvates of 5α-Bromo-6β,19-Epoxy-Androstan-3β,17β-Diol Diacetate","authors":"Josué Vazquez-Chavez,&nbsp;Armando Navarro-Huerta,&nbsp;Marcos Flores-Álamo,&nbsp;Braulio Rodríguez-Molina,&nbsp;Martín A. Iglesias-Arteaga","doi":"10.1002/mrc.5517","DOIUrl":"10.1002/mrc.5517","url":null,"abstract":"<p>The study reports on the rotational dynamics of acetone-<i>d</i>₆ (Form <b>II</b>) and DMSO-<i>d</i>₆ (Form <b>III</b>) within the crystalline structures of two solvates of 5α-bromo-6β,19-epoxy-androstan-3β,17β-diol diacetate (Compound <b>1</b>) by means of solid-state Nuclear Magnetic Resonance through the quadrupolar ²H spin-echo technique. The spectral data allowed the determination of the activation barriers (<i>E</i>_a) for rotation of the solvent molecules, with 6.24 kcal mol⁻¹ for deuterated acetone in the Form <b>II</b>-<i>d</i>_<i>6</i> and 8.19 kcal mol⁻¹ for the case of deuterated dimethylsulfoxide in Form <b>III</b>-<i>d</i>_<i>6</i>. The use of calculations and the Transition State theory through the linear Eyring equation suggested that although the acetone molecules experience a low activation energy (<i>E</i>_<i>a</i> = 6.24 kcal mol⁻¹), a highly ordered transition state during the molecular motion reduces its rotational rate. Conversely, the DMSO molecules, with a higher activation barrier (<i>E</i>_<i>a</i> = 8.19 kcal mol⁻¹) attributed to a denser packing coefficient, have faster motional rates. Based on complementary X-ray and NMR spectroscopy techniques, this work provides detailed insights into the mechanistic phenomena involved in the mobility of small molecules inside crystalline arrangements.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 5-6","pages":"360-369"},"PeriodicalIF":1.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5517","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143449144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Optical Absorption and Electron Paramagnetic Resonance of Cu2+ Incorporated Dicalcium Lead Propionate","authors":"Awadhesh Kumar Yadav,&nbsp;Ram Kripal","doi":"10.1002/mrc.5515","DOIUrl":"10.1002/mrc.5515","url":null,"abstract":"<div>\u0000 \u0000 <p>Following γ-ray exposure, a room-temperature study of electron paramagnetic resonance (EPR) is conducted on Cu²⁺-doped dicalcium lead propionate (DCLP), Ca₂Pb(C₂H₅COO)₆. Cu²⁺ is found at four magnetically equivalent sites replacing Ca²⁺. EPR spectra are fitted to a rhombic symmetry Hamiltonian in order to determine the spin Hamiltonian parameters. The determined parameters are <i>g</i>_<i>x</i> = 2.0245 ± 0.0002, <i>g</i>_<i>y</i> = 2.1024 ± 0.0002, <i>g</i>_<i>z</i> = 2.3476 ± 0.0002, <i>A</i>_<i>x</i> = (56 ± 2) × 10⁻⁴ cm⁻¹, <i>A</i>_<i>y</i> = (78 ± 2) × 10⁻⁴ cm⁻¹, and <i>A</i>_<i>z</i> = (98 ± 2) × 10⁻⁴ cm⁻¹. The experimental value of <i>g</i>-anisotropy is compared with the evaluated one. The wavefunction for the ground state is determined to be 0.999|<i>x</i>² − <i>y</i>²&gt; − 0.004|3<i>z</i>² − <i>r</i>²&gt;. The complex's bonding nature is determined with the aid of an optical study. The optical transitions <i>d</i>_{<i>x</i>2−<i>y</i>2} → <i>d</i>_<i>xy</i>(²B_1g → ²B_2g), <i>d</i>_{<i>x</i>2−<i>y</i>2} → <i>d</i>_{<i>xz</i>,<i>yz</i>}(²B_1g → ²E_g), and <i>d</i>_{<i>x</i>2−<i>y</i>2} → <i>d₃</i>_<i>z</i>2-r2(²B_1g → ²A_1g) are observed at 12,121, 18,691, and 25,316 cm⁻¹, respectively. The molecular orbital coefficients <i>α</i>₀², <i>β</i>₁², <i>β</i>₀², and <i>β</i>′² and Fermi contact term <i>K</i> for Cu²⁺-doped DCLP are found as 0.63, 1.00, 1.00, 0.40, and 0.44, respectively.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 5-6","pages":"350-359"},"PeriodicalIF":1.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143449146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RPA(D) and HRPA(D): Calculating NMR Spin–Spin Coupling Constants in Free Amino Acid Residues","authors":"Christoffer H. S. Møller,&nbsp;Stephan P. A. Sauer","doi":"10.1002/mrc.5514","DOIUrl":"10.1002/mrc.5514","url":null,"abstract":"<p>In the pursuit of computational methods which boast both low computational cost and a high degree of accuracy, the SOPPA-derived methods RPA(D) and HRPA(D) are showing great promise. This study aims to further the benchmarking of these two methods in comparison with both the original SOPPA and the CCSD method by calculating NMR spin–spin coupling constants in the backbone structure of free amino acid residues. Based on a small basis set study, the relative performance of the methods was not found to be heavily dependent on the size of the basis set. While HRPA(D) was found to reproduce the SOPPA results to a consistently high degree of accuracy, RPA(D) reproduced the CCSD results for the one-bond coupling constants more accurately than both HRPA(D) and SOPPA.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 4","pages":"328-345"},"PeriodicalIF":1.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5514","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EPR Spectra Hyperfine Structure of Fluorine-Containing Nitroxide Radicals in Liquid Solutions: Prediction by DFT","authors":"Mikhail V. Matveev,&nbsp;Sergei S. Lunkov,&nbsp;Natalia A. Chumakova","doi":"10.1002/mrc.5513","DOIUrl":"10.1002/mrc.5513","url":null,"abstract":"<div>\u0000 \u0000 <p>Spin trap method allows receiving important information about the structure of short-living intermediate radicals involved in chemical processes. Commonly, the product of a spin trap reaction with an intermediate radical is identified based on the hyperfine structure of its EPR spectrum. However, such identification can be significantly complicated for novel radicals whose spectra are unknown. In this work, we propose a semiquantitative low-cost computation method that allows predicting the hyperfine structure of EPR spectra of the α-phenyl-<i>N</i>-<i>tert</i>-butylnitrone (PBN) adducts with fluorine-containing radicals. The scheme was tested for several radicals containing from 0 to 4 fluorine atoms.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 4","pages":"322-327"},"PeriodicalIF":1.4,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143123202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical Studies on the EPR Parameters and Local Structures for the Orthorhombic and Tetragonal Cu2+ Centers in Cu1−xHxZr2(PO4)3","authors":"Xiaojian Zhao,&nbsp;Yan Liang,&nbsp;Ruizhen Tian,&nbsp;Guijin Li,&nbsp;Xilin Zhou,&nbsp;Zifa Zhou,&nbsp;Xiaolan Zhang","doi":"10.1002/mrc.5509","DOIUrl":"10.1002/mrc.5509","url":null,"abstract":"<div>\u0000 \u0000 <p>The defect structures of the orthorhombical and tetragonal Cu²⁺ centers in Cu_1−<i>x</i>H_<i>x</i>Zr₂(PO₄)₃ are theoretically studied by analyzing their experimental electron paramagnetic resonance (EPR) parameters, based on the perturbation formulas of these parameters for a 3d⁹ ion in orthorhombically and tetragonally elongated octahedra, respectively. The above centers are attributed to the Cu²⁺ ions locating at M(1) site, and the crystal field parameters (CFPs) are quantitatively determined from the superposition model and the local structures of the Cu²⁺ sites. Based on the calculation, the parallel Cu-O bonds may undergo the relative elongations Δ<i>Z</i>_O (≈ 0.113 Å) and Δ<i>Z</i>_T (≈ 0.102 Å) for the orthorhombical and tetragonal Cu²⁺ centers in Cu_1−<i>x</i>H_<i>x</i>Zr₂(PO₄)₃ along <i>z-</i>axis, respectively. Meanwhile, the planar Cu-O bonds are found to experience the relative variation δ<i>r</i> (≈ 0.056 Å) along the <i>x</i>- and <i>y</i>-axes for the orthorhombical Cu²⁺ center because of the Jahn–Teller (JT) effect. The theoretical EPR parameters based on the above local structures agree well with the observed values.</p>\u0000 </div>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"63 4","pages":"314-321"},"PeriodicalIF":1.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143066608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}