Journal articles: 'Electron nuclear double resonance spectroscopy'

1

Eachus, R. S., and M. T. Olm. "Electron Nuclear Double Resonance Spectroscopy." Science 230, no. 4723 (October 18, 1985): 268–74. http://dx.doi.org/10.1126/science.230.4723.268.

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2

Jeschke, Gunnar, and Arthur Schweiger. "Hyperfine-correlated electron nuclear double resonance spectroscopy." Chemical Physics Letters 246, no. 4-5 (December 1995): 431–38. http://dx.doi.org/10.1016/0009-2614(95)01202-4.

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3

Rizzato, Roberto, and Marina Bennati. "Cross-Polarization Electron-Nuclear Double Resonance Spectroscopy." ChemPhysChem 16, no. 18 (November 13, 2015): 3769–73. http://dx.doi.org/10.1002/cphc.201500938.

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4

Mchaourab, Hassane S., T. C. Christidis, and James S. Hyde. "Continuous wave multiquantum electron paramagnetic resonance spectroscopy. IV. Multiquantum electron–nuclear double resonance." Journal of Chemical Physics 99, no. 7 (October 1993): 4975–85. http://dx.doi.org/10.1063/1.465999.

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5

Fahnenschmidt, M., R. Bittl, H. K. Rau, W. Haehnel, and W. Lubitz. "Electron paramagnetic resonance and electron nuclear double resonance spectroscopy of a heme protein maquette." Chemical Physics Letters 323, no. 3-4 (June 2000): 329–39. http://dx.doi.org/10.1016/s0009-2614(00)00530-3.

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KURODA, SHIN-ICHI. "ELECTRON NUCLEAR DOUBLE RESONANCE SPECTROSCOPY OF SOLITONS AND POLARONS IN CONJUGATED POLYMERS." International Journal of Modern Physics B 09, no. 03 (January 30, 1995): 221–60. http://dx.doi.org/10.1142/s0217979295000124.

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Novel elementary excitations such as solitons and polarons in conjugated polymers carry unpaired electrons. In this case electron nuclear double resonance (ENDOR) of protons on the conjugated chain provides a unique method to observe their wavefunctions. This information has two significant meanings. Firstly, it gives the spatial extension of solitons and polarons, the quantity that is essential in examining the reality of these self-localized excitations. Secondly, it directly probes the degree of electron correlation. In the case of finite electron correlation, negative spin sites appear in the spin-density distribution. The unique and detailed determination of the wavefunctions containing such information can be made only after the careful studies of oriented polymers because of the non-single-crystalline nature of these materials. In this article I review our ENDOR studies on solitons in polyacetylene and polarons in poly(paraphenylene vinylene), performed using stretch-oriented samples. All the analyses are based on the properties of π-electrons which show characteristic anisotropy in oriented samples. The observed spin distributions are compared with theoretical results as well as shown as the basis for further analyses of conjugated polymers.

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Milić, Božidar Lj, Sonja M. Djilas, Pavle I. Premović, and Jasna M. Čanadanović-Brunet. "Electron spin resonance and electron nuclear double resonance spectroscopy study of non-dialysable melanoidin pyrolysates." Journal of Analytical and Applied Pyrolysis 21, no. 1-2 (September 1991): 233–37. http://dx.doi.org/10.1016/0165-2370(91)80028-7.

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8

Hoffman, B. M. "Electron-nuclear double resonance spectroscopy (and electron spin-echo envelope modulation spectroscopy) in bioinorganic chemistry." Proceedings of the National Academy of Sciences 100, no. 7 (March 17, 2003): 3575–78. http://dx.doi.org/10.1073/pnas.0636464100.

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9

Webb, Michael I., and Charles J. Walsby. "Albumin binding and ligand-exchange processes of the Ru(iii) anticancer agent NAMI-A and its bis-DMSO analogue determined by ENDOR spectroscopy." Dalton Transactions 44, no. 40 (2015): 17482–93. http://dx.doi.org/10.1039/c5dt02021b.

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10

Baker, G. J., P. F. Knowles, K. B. Pandeya, and J. B. Rayner. "Electron nuclear double-resonance (ENDOR) spectroscopy of amine oxidase from pig plasma." Biochemical Journal 237, no. 2 (July 15, 1986): 609–12. http://dx.doi.org/10.1042/bj2370609.

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Electron nuclear double-resonance (‘ENDOR’) spectroscopic studies on pig plasma amine oxidase have been carried out at 15 K. Deuterium-exchange studies show the presence of two sets of exchangeable protons, probably from two water molecules; from the magnitude of their hyperfine couplings, one is assigned to be equatorially, and the other axially, co-ordinated. Only one 14N hyperfine coupling is observed, suggesting that the bonding of all amino acid (histidine) or organic cofactor ligands is similar. Upon addition of azide, a further hyperfine coupling to nitrogen is observed which is smaller than that observed for the native enzyme; the hyperfine couplings to the remaining nitrogens are slightly altered.

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11

Meyer, B. K. "Electron nuclear double resonance (ENDOR) spectroscopy of the EL2 defect in GaAs." Revue de Physique Appliquée 23, no. 5 (1988): 809–16. http://dx.doi.org/10.1051/rphysap:01988002305080900.

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12

Bravo, D., R. Bottcher, and F. J. Lopez. "Electron nuclear double resonance spectroscopy of Cr3+ions in potassium dihydrogen phosphate." Journal of Physics: Condensed Matter 4, no. 9 (March 2, 1992): 2297–308. http://dx.doi.org/10.1088/0953-8984/4/9/023.

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13

Rautter, J., F. Lendzian, W. Lubitz, S. Wang, and J. P. Allen. "Comparative Study of Reaction Centers from Photosynthetic Purple Bacteria: Electron Paramagnetic Resonance and Electron Nuclear Double Resonance Spectroscopy." Biochemistry 33, no. 40 (October 11, 1994): 12077–84. http://dx.doi.org/10.1021/bi00206a010.

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14

Jeschke, G., and A. Schweiger. "Time‐domain chirp electron nuclear double resonance spectroscopy in one and two dimensions." Journal of Chemical Physics 103, no. 19 (November 15, 1995): 8329–37. http://dx.doi.org/10.1063/1.470145.

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15

Tkach, Igor, Isabel Bejenke, Fabian Hecker, Annemarie Kehl, Müge Kasanmascheff, Igor Gromov, Ion Prisecaru, Peter Höfer, Markus Hiller, and Marina Bennati. "1H high field electron-nuclear double resonance spectroscopy at 263 GHz/9.4 T." Journal of Magnetic Resonance 303 (June 2019): 17–27. http://dx.doi.org/10.1016/j.jmr.2019.04.001.

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16

Kordas, George, and Daniella Goldfarb. "Characterization of borate glasses by W-band pulse electron-nuclear double resonance spectroscopy." Journal of Chemical Physics 129, no. 15 (October 21, 2008): 154502. http://dx.doi.org/10.1063/1.2991171.

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17

EVANS, M. W. "SPECTRAL SPLITTING DUE TO A CIRCULARLY POLARISED PUMP LASER: LASER ZEEMAN SPECTROSCOPY." Modern Physics Letters B 05, no. 16 (July 10, 1991): 1065–73. http://dx.doi.org/10.1142/s0217984991001301.

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Theoretical prediction is made for various types of molecular Zeeman spectroscopy due to a circularly polarised pump laser, in which optical rectification produces a pattern of spectral splitting mediated by the imaginary antisymmetric part of the frequency-dependent molecular polarisability. The hyperfine part of this splitting, in which the nuclear spin quantum number plays a role, leads to the expectation of laser-induced resonance effects akin to conventional nuclear magnetic resonance (NMR) and electron spin resonance (ESR). Experimental conditions for the observation of "laser Zeeman" spectral effects are defined using double resonance and saturation in mode-locked lasers for ultra high resolution.

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18

Filidou, Vasileia, Salvatore Mamone, Stephanie Simmons, Steven D. Karlen, Harry L. Anderson, Christopher W. M. Kay, Alessandro Bagno, et al. "Probing the C 60 triplet state coupling to nuclear spins inside and out." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 1998 (September 13, 2013): 20120475. http://dx.doi.org/10.1098/rsta.2012.0475.

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The photoexcitation of functionalized fullerenes to their paramagnetic triplet electronic state can be studied by pulsed electron paramagnetic resonance (EPR) spectroscopy, whereas the interactions of this state with the surrounding nuclear spins can be observed by a related technique: electron nuclear double resonance (ENDOR). In this study, we present EPR and ENDOR studies on a functionalized exohedral fullerene system, dimethyl[9-hydro (C60-Ih)[5,6]fulleren-1(9 H )-yl]phosphonate (DMHFP), where the triplet electron spin has been used to hyperpolarize, couple and measure two nuclear spins. We go on to discuss the extension of these methods to study a new class of endohedral fullerenes filled with small molecules, such as H 2 @C 60 , and we relate the results to density functional calculations.

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19

Poluektov, Oleg G., and Lisa M. Utschig. "Quantum Sensing of Electron Transfer Pathways in Natural Photosynthesis Using Time-Resolved High-Field Electron Paramagnetic Resonance/Electron–Nuclear Double Resonance Spectroscopy." Journal of Physical Chemistry B 125, no. 16 (April 20, 2021): 4025–30. http://dx.doi.org/10.1021/acs.jpcb.1c00946.

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20

Dauw, X. L. R., G. J. B. van den Berg, D. J. van den Heuvel, O. G. Poluektov, and E. J. J. Groenen. "The triplet wave function of C60 from W-band electron nuclear double resonance spectroscopy." Journal of Chemical Physics 112, no. 16 (April 22, 2000): 7102–10. http://dx.doi.org/10.1063/1.481305.

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21

Schleicher, Erik, Kenichi Hitomi, Christopher W. M. Kay, Elizabeth D. Getzoff, Takeshi Todo, and Stefan Weber. "Electron Nuclear Double Resonance Differentiates Complementary Roles for Active Site Histidines in (6-4) Photolyase." Journal of Biological Chemistry 282, no. 7 (December 12, 2006): 4738–47. http://dx.doi.org/10.1074/jbc.m604734200.

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(6-4) photolyase catalyzes the light-dependent repair of UV-damaged DNA containing (6-4) photoproducts. Blue light excitation of the enzyme generates the neutral FAD radical, FADH·, which is believed to be transiently formed during the enzymatic DNA repair. Here (6-4) photolyase has been examined by optical spectroscopy, electron paramagnetic resonance, and pulsed electron nuclear double resonance spectroscopy. Characterization of selected proton hyperfine couplings of FADH·, namely those of H8α and H1′, yields information on the micropolarity at the site where the DNA substrate is expected to bind. Shifts in the hyperfine couplings as a function of structural modifications induced by point mutations and pH changes distinguish the protonation states of two highly conserved histidines, His354 and His358, in Xenopus laevis (6-4) photolyase. These are proposed to catalyze formation of the oxetane intermediate that precedes light-initiated DNA repair. The results show that at pH 9.5, where the enzymatic repair activity is highest, His358 is deprotonated, whereas His354 is protonated. Hence, the latter is likely the proton donor that initiates oxetane formation from the (6-4) photoproduct.

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22

Lubitz, Wolfgang. "Photochemical processes in photosynthesis studied by advanced electron paramagnetic resonance techniques." Pure and Applied Chemistry 75, no. 8 (January 1, 2003): 1021–30. http://dx.doi.org/10.1351/pac200375081021.

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Various continuous-wave and pulse electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) experiments performed on the radical species occurring in photosynthetic reaction centers of plants and bacteria during light-induced charge separation are reviewed here. Emphasis is placed on time-resolved experiments performed on short-lived intermediate states such as radical pairs and triplet states for which also hyperfine information can be obtained from pulse ENDOR spectroscopy. Detailed insight into the electronic structure of these intermediates and their interaction with the protein environment is now becoming available.

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23

McLauchlan, K. A. "Electron Nuclear Double Resonance Spectroscopy of Radicals in Solution. Application to Organic and Biological Chemistry." Journal of Photochemistry and Photobiology A: Chemistry 46, no. 3 (March 1989): 391. http://dx.doi.org/10.1016/1010-6030(89)87055-8.

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24

Kevan, Larry. "Electron-nuclear double resonance spectroscopy of radicals in solution: Application to organic and biological chemistry." Journal of Magnetic Resonance (1969) 80, no. 3 (December 1988): 563. http://dx.doi.org/10.1016/0022-2364(88)90256-9.

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25

Savchenko, Dariya V., Ekaterina N. Kalabukhova, Evgeniy N. Mokhov, and Andreas Pöppl. "Superhyperfine Interactions of the Nitrogen Donors in 4H SiC Studied by Pulsed ENDOR and TRIPLE ENDOR Spectroscopy." Materials Science Forum 740-742 (January 2013): 439–42. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.439.

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The nitrogen donors residing at quasi-cubic lattice site (Nk) in 4H SiC were investigated by field sweep electron spin echo (FS ESE), pulsed electron nuclear double resonance (ENDOR) and pulsed General TRIPLE ENDOR spectroscopy. The 29Si and 13C superhyperfine lines observed in the FS ESE and ENDOR spectra of Nk in n-type 6H SiC were assigned by pulsed General TRIPLE resonance spectroscopy to the specific carbon (C) and silicon (Si) atoms located in the nearest environment of Nk in 4H SiC. The superhyperfine interaction constants and their relative signs for Nk with 29Si and 13C nuclei located in the nearest-neighbor shells are found from the General TRIPLE ENDOR spectra to be positive for C atoms and negative for Si atoms.

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26

Sar, Suchandra, Lena Sundqvist Ökvist, Tobias Sparrman, Fredrik Engström, and Caisa Samuelsson. "Characterization of Double Leached Waelz Oxide for Identification of Fluoride Mineral." Metals 9, no. 3 (March 20, 2019): 361. http://dx.doi.org/10.3390/met9030361.

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Double leached Waelz oxide (DLWO), with 76% zinc, is a secondary zinc containing raw materials obtained by the treatment of electric arc furnace dust. The content of fluoride in DLWO is still too high for direct leaching, as fluoride has a detrimental effect on electrowinning for zinc production. Knowledge of the characteristics of DLWO, and especially on how a fluoride mineral might exist, can contribute to further improvement of the selective leaching for the removal of fluoride. In this study, DLWO was characterized using analytical techniques, such as inductively coupled plasma-optical emission spectroscopy (ICP-OES), 19F liquid-state nuclear magnetic resonance (19F LS NMR), X-ray powder diffraction analysis (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and 19F solid-state nuclear magnetic resonance (19F SS NMR). This study showed that DLWO mainly consisted of zincite (ZnO), cerussite (PbCO3) and a spinel containing zinc, iron and manganese. The fluoride mineral identified was calcium fluoride (CaF2). In SEM analysis, fluorine was found in larger grains together with calcium and oxygen, which was possibly calcium carbonate.

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27

Orlinskii, S. B., I. V. Borovykh, V. Zielke, and H. J. Steinhoff. "Use of spin labels to study membrane proteins by high-frequency electron nuclear double resonance spectroscopy." JETP Letters 86, no. 2 (September 2007): 149–52. http://dx.doi.org/10.1134/s0021364007140172.

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28

Clarkson, R. B., R. L. Belford, and C. Reiner. "A surface acoustic wave oscillator‐based modulator/mixer for frequency‐modulated electron nuclear double resonance spectroscopy." Review of Scientific Instruments 61, no. 11 (November 1990): 3356–59. http://dx.doi.org/10.1063/1.1141583.

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29

Finazzo, Cinzia, Sabine Van Doorslaer, and Arthur Schweiger. "Solvent effects of cobalt(II) phthalocyanine in sulfuric acid: a continuous wave and pulse EPR study." Journal of Porphyrins and Phthalocyanines 07, no. 02 (February 2003): 89–96. http://dx.doi.org/10.1142/s1088424603000124.

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Products based on metal phthalocyanines are widely used in industry. In the processing of these materials it is essential to control the conditions of the matrix the metal phthalocyanines are embedded in. Using the example of cobalt(II) phthalocyanine in sulfuric acid we show that continuous wave and pulse electron paramagnetic resonance and electron nuclear double resonance spectroscopy provide excellent tools to monitor the influence of the matrix on paramagnetic phthalocyanines. The g values, the cobalt hyperfine values, and the hyperfine and nuclear quadrupole couplings of the isoindole nitrogens, as well as the hyperfine interactions of the surrounding protons allow for a detailed assessment of the electronic structure of cobalt(II) phthalocyanine in sulfuric acid. Subtle differences between the system under study and related Co ( II ) porphyrin and corrin systems could be traced.

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30

DeRose, Victoria J., Jonathan C. G. Woo, William P. Hawe, Brian M. Hoffman, Richard B. Silverman, and Kemal Yelekci. "Observation of a Flavin Semiquinone in the Resting State of Monoamine Oxidase B by Electron Paramagnetic Resonance and Electron Nuclear Double Resonance Spectroscopy†,‡." Biochemistry 35, no. 34 (January 1996): 11085–91. http://dx.doi.org/10.1021/bi960749f.

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31

Bennebroek, M. T., O. G. Poluektov, A. J. Zakrzewski, P. G. Baranov, and J. Schmidt. "Structure of the Intrinsic Shallow Electron Center in AgCl Studied by Pulsed Electron Nuclear Double Resonance Spectroscopy at 95 GHz." Physical Review Letters 74, no. 3 (January 16, 1995): 442–45. http://dx.doi.org/10.1103/physrevlett.74.442.

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32

Mustafi, D., and Y. Nakagawa. "Characterization of calcium-binding sites in the kidney stone inhibitor glycoprotein nephrocalcin with vanadyl ions: electron paramagnetic resonance and electron nuclear double resonance spectroscopy." Proceedings of the National Academy of Sciences 91, no. 24 (November 22, 1994): 11323–27. http://dx.doi.org/10.1073/pnas.91.24.11323.

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33

Davydov, Roman, Sangchoul Im, Muralidharan Shanmugam, William A. Gunderson, Naw May Pearl, Brian M. Hoffman, and Lucy Waskell. "Role of the Proximal Cysteine Hydrogen Bonding Interaction in Cytochrome P450 2B4 Studied by Cryoreduction, Electron Paramagnetic Resonance, and Electron–Nuclear Double Resonance Spectroscopy." Biochemistry 55, no. 6 (February 3, 2016): 869–83. http://dx.doi.org/10.1021/acs.biochem.5b00744.

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34

Tkach, Igor, Giuseppe Sicoli, Claudia Höbartner, and Marina Bennati. "A dual-mode microwave resonator for double electron–electron spin resonance spectroscopy at W-band microwave frequencies." Journal of Magnetic Resonance 209, no. 2 (April 2011): 341–46. http://dx.doi.org/10.1016/j.jmr.2011.01.012.

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35

Edmondson, Dale E., and Susan C. D'Ardenne. "Electron-nuclear double resonance spectroscopy of the desulfo-inhibited molybdenum(V) center in bovine milk xanthine oxidase." Biochemistry 28, no. 14 (July 11, 1989): 5924–30. http://dx.doi.org/10.1021/bi00440a032.

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36

Mustafi, Devkumar, Mona M. Knock, Robert W. Shaw, and Marvin W. Makinen. "Conformational Changes in Spin-Labeled Cephalosporin and Penicillin upon Hydrolysis Revealed by Electron Nuclear Double Resonance Spectroscopy." Journal of the American Chemical Society 119, no. 51 (December 1997): 12619–28. http://dx.doi.org/10.1021/ja971717y.

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37

Mustafi, D., and M. W. Makinen. "Structure and conformation of nitroxyl spin-label compounds in frozen solutions by electron nuclear double resonance spectroscopy." Applied Magnetic Resonance 3, no. 2 (April 1992): 321–31. http://dx.doi.org/10.1007/bf03166701.

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38

Murzakhanov, Fadis F., Peter O. Grishin, Margarita A. Goldberg, Boris V. Yavkin, Georgy V. Mamin, Sergei B. Orlinskii, Alexander Yu Fedotov, et al. "Radiation-Induced Stable Radicals in Calcium Phosphates: Results of Multifrequency EPR, EDNMR, ESEEM, and ENDOR Studies." Applied Sciences 11, no. 16 (August 22, 2021): 7727. http://dx.doi.org/10.3390/app11167727.

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This article presents the results of a study of radiation-induced defects in various synthetic calcium phosphate (CP) powder materials (hydroxyapatite—HA and octacalcium phosphate—OCP) by electron paramagnetic resonance (EPR) spectroscopy at the X, Q, and W-bands (9, 34, 95 GHz for the microwave frequencies, respectively). Currently, CP materials are widely used in orthopedics and dentistry owing to their high biocompatibility and physico-chemical similarity with human hard tissue. It is shown that in addition to the classical EPR techniques, other experimental approaches such as ELDOR-detected NMR (EDNMR), electron spin echo envelope modulation (ESEEM), and electron-nuclear double resonance (ENDOR) can be used to analyze the electron–nuclear interactions of CP powders. We demonstrated that the value and angular dependence of the quadrupole interaction for 14N nuclei of a nitrate radical can be determined by the EDNMR method at room temperature. The ESEEM technique has allowed for a rapid analysis of the nuclear environment and estimation of the structural positions of radiation-induced centers in various crystal matrices. ENDOR spectra can provide information about the distribution of the nitrate radicals in the OCP structure.

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39

Möbius, Klaus, Wolfgang Lubitz, Nicholas Cox, and Anton Savitsky. "Biomolecular EPR Meets NMR at High Magnetic Fields." Magnetochemistry 4, no. 4 (November 6, 2018): 50. http://dx.doi.org/10.3390/magnetochemistry4040050.

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In this review on advanced biomolecular EPR spectroscopy, which addresses both the EPR and NMR communities, considerable emphasis is put on delineating the complementarity of NMR and EPR regarding the measurement of interactions and dynamics of large molecules embedded in fluid-solution or solid-state environments. Our focus is on the characterization of protein structure, dynamics and interactions, using sophisticated EPR spectroscopy methods. New developments in pulsed microwave and sweepable cryomagnet technology as well as ultrafast electronics for signal data handling and processing have pushed the limits of EPR spectroscopy to new horizons reaching millimeter and sub-millimeter wavelengths and 15 T Zeeman fields. Expanding traditional applications to paramagnetic systems, spin-labeling of biomolecules has become a mainstream multifrequency approach in EPR spectroscopy. In the high-frequency/high-field EPR region, sub-micromolar concentrations of nitroxide spin-labeled molecules are now sufficient to characterize reaction intermediates of complex biomolecular processes. This offers promising analytical applications in biochemistry and molecular biology where sample material is often difficult to prepare in sufficient concentration for NMR characterization. For multifrequency EPR experiments on frozen solutions typical sample volumes are of the order of 250 μL (S-band), 150 μL (X-band), 10 μL (Q-band) and 1 μL (W-band). These are orders of magnitude smaller than the sample volumes required for modern liquid- or solid-state NMR spectroscopy. An important additional advantage of EPR over NMR is the ability to detect and characterize even short-lived paramagnetic reaction intermediates (down to a lifetime of a few ns). Electron–nuclear and electron–electron double-resonance techniques such as electron–nuclear double resonance (ENDOR), ELDOR-detected NMR, PELDOR (DEER) further improve the spectroscopic selectivity for the various magnetic interactions and their evolution in the frequency and time domains. PELDOR techniques applied to frozen-solution samples of doubly spin-labeled proteins allow for molecular distance measurements ranging up to about 100 Å. For disordered frozen-solution samples high-field EPR spectroscopy allows greatly improved orientational selection of the molecules within the laboratory axes reference system by means of the anisotropic electron Zeeman interaction. Single-crystal resolution is approached at the canonical g-tensor orientations—even for molecules with very small g-anisotropies. Unique structural, functional, and dynamic information about molecular systems is thus revealed that can hardly be obtained by other analytical techniques. On the other hand, the limitation to systems with unpaired electrons means that EPR is less widely used than NMR. However, this limitation also means that EPR offers greater specificity, since ordinary chemical solvents and matrices do not give rise to EPR in contrast to NMR spectra. Thus, multifrequency EPR spectroscopy plays an important role in better understanding paramagnetic species such as organic and inorganic radicals, transition metal complexes as found in many catalysts or metalloenzymes, transient species such as light-generated spin-correlated radical pairs and triplets occurring in protein complexes of photosynthetic reaction centers, electron-transfer relays, etc. Special attention is drawn to high-field EPR experiments on photosynthetic reaction centers embedded in specific sugar matrices that enable organisms to survive extreme dryness and heat stress by adopting an anhydrobiotic state. After a more general overview on methods and applications of advanced multifrequency EPR spectroscopy, a few representative examples are reviewed to some detail in two Case Studies: (I) High-field ELDOR-detected NMR (EDNMR) as a general method for electron–nuclear hyperfine spectroscopy of nitroxide radical and transition metal containing systems; (II) High-field ENDOR and EDNMR studies of the Oxygen Evolving Complex (OEC) in Photosystem II, which performs water oxidation in photosynthesis, i.e., the light-driven splitting of water into its elemental constituents, which is one of the most important chemical reactions on Earth.

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40

George, G. N., R. E. Bare, H. Y. Jin, E. I. Stiefel, and R. C. Prince. "E.p.r.-spectroscopic studies on the molybdenum–iron site of nitrogenase from Clostridium pasteurianum." Biochemical Journal 262, no. 1 (August 15, 1989): 349–52. http://dx.doi.org/10.1042/bj2620349.

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The e.p.r. spectroscopy of the nitrogenase molybdenum-iron protein from Clostridium pasteurianum was re-investigated. The sharpness of the delta Ms = +/- 3 g′z peak from the +/- 3/2 Kramer's doublet enables the observation and quantification of incompletely resolved hyperfine splittings from the stable magnetic nuclei 95Mo and 57Fe in samples enriched in these isotopes. No couplings to 1H or 17O could be discerned by examination of spectra from samples exchanged into 2H2O and H2(17)O respectively. Simulation of the spectrum from 95Mo-enriched samples yields a hyperfine coupling of 2.9 MHz, and indicates that the earlier electron-nuclear-double-resonance-derived estimate of 8.1 +/- 0.2 MHz is substantially in error.

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41

Antuzevics, Andris, Guna Krieke, Haralds Ozols, Andris Fedotovs, Anatolijs Sarakovskis, and Alexei Kuzmin. "Oxidation State and Local Structure of Chromium Ions in LaOCl." Materials 14, no. 13 (June 25, 2021): 3539. http://dx.doi.org/10.3390/ma14133539.

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LaOCl doped with 0–10 mol% Cr was synthesized by thermal decomposition of chlorides. X-ray diffraction (XRD) analysis revealed that incorporation of chromium results in a decrease of the lattice parameter a and a simultaneous increase of the lattice parameter c. The local structure of chromium ions was studied with X-ray photoelectron (XPS), X-ray absorption (XANES), multifrequency electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) spectroscopy techniques. It was determined that synthesis in oxidizing atmosphere promotes the incorporation of chromium ions predominantly in the 5+ oxidation state. Changes of chromium oxidation state and local environment occur after a subsequent treatment in reducing atmosphere. Spin-Hamiltonian (SH) parameters for a Cr5+ and two types of Cr3+ centers in LaOCl were determined from the EPR spectra simulations.

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42

Pokern, Yvo, Benjamin Eltzner, Stephan F. Huckemann, Clemens Beeken, JoAnne Stubbe, Igor Tkach, Marina Bennati, and Markus Hiller. "Statistical analysis of ENDOR spectra." Proceedings of the National Academy of Sciences 118, no. 27 (July 2, 2021): e2023615118. http://dx.doi.org/10.1073/pnas.2023615118.

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Electron–nuclear double resonance (ENDOR) measures the hyperfine interaction of magnetic nuclei with paramagnetic centers and is hence a powerful tool for spectroscopic investigations extending from biophysics to material science. Progress in microwave technology and the recent availability of commercial electron paramagnetic resonance (EPR) spectrometers up to an electron Larmor frequency of 263 GHz now open the opportunity for a more quantitative spectral analysis. Using representative spectra of a prototype amino acid radical in a biologically relevant enzyme, the Y122• in Escherichia coli ribonucleotide reductase, we developed a statistical model for ENDOR data and conducted statistical inference on the spectra including uncertainty estimation and hypothesis testing. Our approach in conjunction with 1H/2H isotopic labeling of Y122• in the protein unambiguously established new unexpected spectral contributions. Density functional theory (DFT) calculations and ENDOR spectral simulations indicated that these features result from the beta-methylene hyperfine coupling and are caused by a distribution of molecular conformations, likely important for the biological function of this essential radical. The results demonstrate that model-based statistical analysis in combination with state-of-the-art spectroscopy accesses information hitherto beyond standard approaches.

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Bradtmüller, Henrik, Long Zhang, Carla C. de Araujo, Hellmut Eckert, Doris Möncke, and Doris Ehrt. "Structural Studies of NaPO3–AlF3 Glasses by High-Resolution Double-Resonance Nuclear Magnetic Resonance Spectroscopy." Journal of Physical Chemistry C 122, no. 37 (August 21, 2018): 21579–88. http://dx.doi.org/10.1021/acs.jpcc.8b06162.

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44

BUTLER, Clive S., Shirley A. FAIRHURST, Stuart J. FERGUSON, Andrew J. THOMSON, Ben C. BERKS, David J. RICHARDSON, and David J. LOWE. "Mo(V) co-ordination in the periplasmic nitrate reductase from Paracoccus pantotrophus probed by electron nuclear double resonance (ENDOR) spectroscopy." Biochemical Journal 363, no. 3 (April 24, 2002): 817–23. http://dx.doi.org/10.1042/bj3630817.

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Abstract:

The first electron nuclear double resonance (ENDOR) study of a member of the Mo-bis-molybdopterin guanine dinucleotide family of molybdoenzymes is presented, using the periplasmic nitrate reductase from Paracoccus pantotrophus. Rapid freeze-quenched time-resolved EPR revealed that during turnover the intensity of a Mo(V) EPR signal known as High-g [resting] increases. This signal is split by two interacting protons that are not solvent-exchangeable. X-band proton-ENDOR analysis resolved broad symmetrical resonance features that arose from four classes of protons weakly coupled to the Mo(V). Signals from two of these were lost upon exchange into deuterated buffer, suggesting that they may originate from OH− or H2O groups. One of these signals was also lost when the enzyme was redox-cycled in the presence of azide. Since these protons are very weakly coupled OH/H2O groups, they are not likely to be ligated directly to the Mo(V). This suggests that protonation of a Mo(VI)=O group does not occur on reduction to Mo(V), but most probably accompanies reduction of Mo(V) to Mo(IV). A resonance feature from a more strongly coupled proton, that was not lost following exchange into deuterated buffer, could also be resolved at 22–24MHz. The anisotropy of this feature, determined from ENDOR spectra collected at a range of field positions, indicated a Mo—proton distance of approx. 3.2Å, consistent with this being one of the β-methylene protons of a Mo—Cys ligand.

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Ristori, Sandra, M. Francesca Ottaviani, and Giacomo Martini. "Structure and mobility of vanadyl(2+) ion in water adsorbed onto silica gels studied by X- and S-band electron spin resonance spectroscopy and by electron nuclear double resonance spectroscopy." Langmuir 7, no. 4 (April 1991): 755–59. http://dx.doi.org/10.1021/la00052a025.

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46

McNaughton, R. L., A. R. Reddi, M. H. S. Clement, A. Sharma, K. Barnese, L. Rosenfeld, E. B. Gralla, J. S. Valentine, V. C. Culotta, and B. M. Hoffman. "Probing in vivo Mn2+ speciation and oxidative stress resistance in yeast cells with electron-nuclear double resonance spectroscopy." Proceedings of the National Academy of Sciences 107, no. 35 (August 11, 2010): 15335–39. http://dx.doi.org/10.1073/pnas.1009648107.

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47

Rigby, Stephen E. J., Michael C. W. Evans, and Peter Heathcote. "Electron nuclear double resonance (ENDOR) spectroscopy of radicals in photosystem I and related Type 1 photosynthetic reaction centres." Biochimica et Biophysica Acta (BBA) - Bioenergetics 1507, no. 1-3 (October 2001): 247–59. http://dx.doi.org/10.1016/s0005-2728(01)00211-0.

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Shi, Wenjun, Curtis W. Hoganson, Matthew Espe, Christopher J. Bender, Gerald T. Babcock, Graham Palmer, Richard J. Kulmacz, and Ah-lim Tsai. "Electron Paramagnetic Resonance and Electron Nuclear Double Resonance Spectroscopic Identification and Characterization of the Tyrosyl Radicals in Prostaglandin H Synthase 1†." Biochemistry 39, no. 14 (April 2000): 4112–21. http://dx.doi.org/10.1021/bi992561c.

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Baine, Terrence J., and Einar Sagstuen. "Radiation-Induced Radical Formation in β-Glycerophosphate Single Crystals Studied by Electron Paramagnetic Resonance and Electron Nuclear Double Resonance Spectroscopy: Formation of an Allylic-Type Radical." Radiation Research 150, no. 2 (August 1998): 148. http://dx.doi.org/10.2307/3579850.

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Hoganson, Curtis W., and Gerald T. Babcock. "Protein-tyrosyl radical interactions in photosystem II studied by electron spin resonance and electron nuclear double resonance spectroscopy: comparison with ribonucleotide reductase and in vitro tyrosine." Biochemistry 31, no. 47 (December 1992): 11874–80. http://dx.doi.org/10.1021/bi00162a028.

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Journal articles on the topic 'Electron nuclear double resonance spectroscopy'

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