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Gupta P, Akhtar N, Begum W, Rana B, Kalita R, Chauhan M, Thadhani C, Manna K. Metal-Organic Framework-Supported Mono Bipyridyl-Iron Hydroxyl Catalyst for Selective Benzene Hydroxylation into Phenol. Inorg Chem 2024; 63:11907-11916. [PMID: 38850244 DOI: 10.1021/acs.inorgchem.4c01825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2024]
Abstract
Direct hydroxylation of benzene to phenol is more appealing in the industry for the economic and environmentally friendly phenol synthesis than the conventional cumene process. We have developed a UiO-metal-organic framework (MOF)-supported mono bipyridyl-Iron(II) hydroxyl catalyst [bpy-UiO-Fe(OH)2] for the selective benzene hydroxylation into phenol using H2O2 as the oxidant. The heterogeneous bpy-UiO-Fe(OH)2 catalyst showed high activity and remarkable phenol selectivity of 99%, giving the phenol mass-specific activity up to 1261 mmolPhOHgFe-1 h-1 at 60 °C. Bpy-UiO-Fe(OH)2 is significantly more active and selective than its homogeneous counterpart, bipyridine-Fe(OH)2. This enhanced catalytic activity of bpy-UiO-Fe(OH)2 over its homogeneous control is attributed to the active site isolation of the bpy-Fe(OH)2 moiety by the solid MOF that prevents intermolecular decomposition. Moreover, the exceptional selectivity of bpy-UiO-Fe(OH)2 in benzene to phenol conversion is originated via shape-selective catalysis, where the confined reaction space within the porous UiO-MOF prevents the formation of larger overoxidized products such as hydroquinone or benzoquinone, leading to the formation of only smaller-sized phenol after monohydroxylation of benzene. Spectroscopic and controlled experiments and theoretical calculations elucidated the reaction pathway, in which the in situ generated •OH radical mediated by bpy-UiO-FeII(OH)2 is the key species for benzene hydroxylation. This work underscores the significance of MOF-supported earth-abundant metal catalysts for sustainable production of fine chemicals.
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Affiliation(s)
- Poorvi Gupta
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Naved Akhtar
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Wahida Begum
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Bharti Rana
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Rahul Kalita
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Manav Chauhan
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Chhaya Thadhani
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Kuntal Manna
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Hand AT, Watson-Sanders BD, Xue ZL. Spectroscopic techniques to probe magnetic anisotropy and spin-phonon coupling in metal complexes. Dalton Trans 2024; 53:4390-4405. [PMID: 38380640 DOI: 10.1039/d3dt03609j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Magnetism of molecular quantum materials such as single-molecule magnets (SMMs) has been actively studied for potential applications in the new generation of high-density data storage using SMMs and quantum information science. Magnetic anisotropy and spin-phonon coupling are two key properties of d- and f-metal complexes. Here, phonons refer to both intermolecular and intramolecular vibrations. Direct determination of magnetic anisotropy and experimental studies of spin-phonon coupling are critical to the understanding of molecular magnetism. This article discusses our recent approach in using three complementary techniques, far-IR and Raman magneto-spectroscopies (FIRMS and RaMS, respectively) and inelastic neutron scatterings (INS), to determine magnetic excited states. Spin-phonon couplings are observed in FIRMS and RaMS. DFT phonon calculations give energies and symmetries of phonons as well as calculated INS spectra which help identify magnetic peaks in experimental INS spectra.
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Affiliation(s)
- Adam T Hand
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
| | | | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
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3
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Moseley DH, Liu Z, Bone AN, Stavretis SE, Singh SK, Atanasov M, Lu Z, Ozerov M, Thirunavukkuarasu K, Cheng Y, Daemen LL, Lubert-Perquel D, Smirnov D, Neese F, Ramirez-Cuesta AJ, Hill S, Dunbar KR, Xue ZL. Comprehensive Studies of Magnetic Transitions and Spin-Phonon Couplings in the Tetrahedral Cobalt Complex Co(AsPh 3) 2I 2. Inorg Chem 2022; 61:17123-17136. [PMID: 36264658 DOI: 10.1021/acs.inorgchem.2c02604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combination of inelastic neutron scattering (INS), far-IR magneto-spectroscopy (FIRMS), and Raman magneto-spectroscopy (RaMS) has been used to comprehensively probe magnetic excitations in Co(AsPh3)2I2 (1), a reported single-molecule magnet (SMM). With applied field, the magnetic zero-field splitting (ZFS) peak (2D') shifts to higher energies in each spectroscopy. INS placed the ZFS peak at 54 cm-1, as revealed by both variable-temperature (VT) and variable-magnetic-field data, giving results that agree well with those from both far-IR and Raman studies. Both FIRMS and RaMS also reveal the presence of multiple spin-phonon couplings as avoided crossings with neighboring phonons. Here, phonons refer to both intramolecular and lattice vibrations. The results constitute a rare case in which the spin-phonon couplings are observed with both Raman-active (g modes) and far-IR-active phonons (u modes; space group P21/c, no. 14, Z = 4 for 1). These couplings are fit using a simple avoided crossing model with coupling constants of ca. 1-2 cm-1. The combined spectroscopies accurately determine the magnetic excited level and the interaction of the magnetic excitation with phonon modes. Density functional theory (DFT) phonon calculations compare well with INS, allowing for the assignment of the modes and their symmetries. Electronic calculations elucidate the nature of ZFS in the complex. Features of different techniques to determine ZFS and other spin-Hamiltonian parameters in transition-metal complexes are summarized.
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Affiliation(s)
- Duncan H Moseley
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Zhiming Liu
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Alexandria N Bone
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Shelby E Stavretis
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Saurabh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, 502285Sangareddy, Telangana, India
| | - Mihail Atanasov
- Max Planck Institute for Coal Research, Kaiser-Wilhelm-Platz 1, D-45470Mülheim an der Ruhr, Germany.,Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113Sofia, Bulgaria
| | - Zhengguang Lu
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | | | - Yongqiang Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Luke L Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Daphné Lubert-Perquel
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | - Frank Neese
- Max Planck Institute for Coal Research, Kaiser-Wilhelm-Platz 1, D-45470Mülheim an der Ruhr, Germany
| | - A J Ramirez-Cuesta
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas77843, United States
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
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4
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Moseley DH, Stavretis SE, Thirunavukkuarasu K, Ozerov M, Cheng Y, Daemen LL, Ludwig J, Lu Z, Smirnov D, Brown CM, Pandey A, Ramirez-Cuesta AJ, Lamb AC, Atanasov M, Bill E, Neese F, Xue ZL. Spin-phonon couplings in transition metal complexes with slow magnetic relaxation. Nat Commun 2018; 9:2572. [PMID: 29968702 PMCID: PMC6030095 DOI: 10.1038/s41467-018-04896-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 05/18/2018] [Indexed: 11/28/2022] Open
Abstract
Spin–phonon coupling plays an important role in single-molecule magnets and molecular qubits. However, there have been few detailed studies of its nature. Here, we show for the first time distinct couplings of g phonons of CoII(acac)2(H2O)2 (acac = acetylacetonate) and its deuterated analogs with zero-field-split, excited magnetic/spin levels (Kramers doublet (KD)) of the S = 3/2 electronic ground state. The couplings are observed as avoided crossings in magnetic-field-dependent Raman spectra with coupling constants of 1–2 cm−1. Far-IR spectra reveal the magnetic-dipole-allowed, inter-KD transition, shifting to higher energy with increasing field. Density functional theory calculations are used to rationalize energies and symmetries of the phonons. A vibronic coupling model, supported by electronic structure calculations, is proposed to rationalize the behavior of the coupled Raman peaks. This work spectroscopically reveals and quantitates the spin–phonon couplings in typical transition metal complexes and sheds light on the origin of the spin–phonon entanglement. Transition metal complexes that display slow magnetic relaxation show promise for information storage, but our mechanistic understanding of the magnetic relaxation of such compounds remains limited. Here, the authors spectroscopically and computationally characterize the strength of spin–phonon couplings, which play an important role in the relaxation process.
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Affiliation(s)
- Duncan H Moseley
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | - Shelby E Stavretis
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | | | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Yongqiang Cheng
- Chemical and Engineering Materials Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Luke L Daemen
- Chemical and Engineering Materials Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Jonathan Ludwig
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Zhengguang Lu
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Craig M Brown
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Anup Pandey
- Chemical and Engineering Materials Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - A J Ramirez-Cuesta
- Chemical and Engineering Materials Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Adam C Lamb
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | - Mihail Atanasov
- Max Planck Institute for Coal Research, Kaiser-Wilhelm-Platz 1, D-45470, Mülheim an der Ruhr, Germany. .,Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria.
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, D-45470, Mülheim an der Ruhr, Germany.
| | - Frank Neese
- Max Planck Institute for Coal Research, Kaiser-Wilhelm-Platz 1, D-45470, Mülheim an der Ruhr, Germany
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
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Li GL, Wu SQ, Zhang LF, Wang Z, Ouyang ZW, Ni ZH, Su SQ, Yao ZS, Li JQ, Sato O. Field-Induced Slow Magnetic Relaxation in an Octacoordinated Fe(II) Complex with Pseudo-D2d Symmetry: Magnetic, HF-EPR, and Theoretical Investigations. Inorg Chem 2017; 56:8018-8025. [DOI: 10.1021/acs.inorgchem.7b00765] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Guo-Ling Li
- Institute for Materials Chemistry and Engineering & IRCCS, Kyushu University, 744 Motooka Nishi-ku, 819-0395 Fukuoka, Japan
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People’s Republic of China
| | - Shu-Qi Wu
- Institute for Materials Chemistry and Engineering & IRCCS, Kyushu University, 744 Motooka Nishi-ku, 819-0395 Fukuoka, Japan
| | - Li-Fang Zhang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People’s Republic of China
| | - Zhenxing Wang
- Wuhan National High Magnetic
Field Center, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
| | - Zhong-Wen Ouyang
- Wuhan National High Magnetic
Field Center, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
| | - Zhong-Hai Ni
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People’s Republic of China
| | - Sheng-Qun Su
- Institute for Materials Chemistry and Engineering & IRCCS, Kyushu University, 744 Motooka Nishi-ku, 819-0395 Fukuoka, Japan
| | - Zi-Shuo Yao
- Institute for Materials Chemistry and Engineering & IRCCS, Kyushu University, 744 Motooka Nishi-ku, 819-0395 Fukuoka, Japan
| | - Jun-Qiu Li
- Institute for Materials Chemistry and Engineering & IRCCS, Kyushu University, 744 Motooka Nishi-ku, 819-0395 Fukuoka, Japan
| | - Osamu Sato
- Institute for Materials Chemistry and Engineering & IRCCS, Kyushu University, 744 Motooka Nishi-ku, 819-0395 Fukuoka, Japan
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Pastushenko A, Lysenko V. Electrochemical synthesis of luminescent ferrous fluorosilicate hexahydrate (FeSiF6·6H2O) nano-powders. RSC Adv 2016. [DOI: 10.1039/c5ra25183d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Electrochemical etching of metallurgical FeSi2/Si substrate produces ferrous fluorosilicate hexahydrate (FeSiF6·6H2O) nano-powder with strong and stable photoluminescence.
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Affiliation(s)
- A. Pastushenko
- Nanotechnology Institute of Lyon
- University Lyon 1
- UMR CNRS 5270
- INSA Lyon
- 69621 Villeurbanne
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Krzystek J, Telser J. Measuring giant anisotropy in paramagnetic transition metal complexes with relevance to single-ion magnetism. Dalton Trans 2016; 45:16751-16763. [DOI: 10.1039/c6dt01754a] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
“Giant magnetic anisotropy” is a phenomenon identified in certain coordination complexes of nd- and nf-block ions. The strengths and weaknesses of multiple methods used to measure it are evaluated.
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Affiliation(s)
- J. Krzystek
- National High Magnetic Field Laboratory
- Florida State University
- Tallahassee
- USA
| | - Joshua Telser
- Department of Biological
- Chemical and Physical Sciences
- Roosevelt University
- Chicago
- USA
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8
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Jiang SD, Maganas D, Levesanos N, Ferentinos E, Haas S, Thirunavukkuarasu K, Krzystek J, Dressel M, Bogani L, Neese F, Kyritsis P. Direct Observation of Very Large Zero-Field Splitting in a Tetrahedral Ni(II)Se4 Coordination Complex. J Am Chem Soc 2015; 137:12923-8. [PMID: 26352187 DOI: 10.1021/jacs.5b06716] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The high-spin (S = 1) tetrahedral Ni(II) complex [Ni{(i)Pr2P(Se)NP(Se)(i)Pr2}2] was investigated by magnetometry, spectroscopic, and quantum chemical methods. Angle-resolved magnetometry studies revealed the orientation of the magnetization principal axes. The very large zero-field splitting (zfs), D = 45.40(2) cm(-1), E = 1.91(2) cm(-1), of the complex was accurately determined by far-infrared magnetic spectroscopy, directly observing transitions between the spin sublevels of the triplet ground state. These are the largest zfs values ever determined--directly--for a high-spin Ni(II) complex. Ab initio calculations further probed the electronic structure of the system, elucidating the factors controlling the sign and magnitude of D. The latter is dominated by spin-orbit coupling contributions of the Ni ions, whereas the corresponding effects of the Se atoms are remarkably smaller.
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Affiliation(s)
- Shang-Da Jiang
- 1. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, D-70550, Stuttgart, Germany
| | - Dimitrios Maganas
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Nikolaos Levesanos
- Laboratory of Inorganic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens, 157 71 Greece
| | - Eleftherios Ferentinos
- Laboratory of Inorganic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens, 157 71 Greece
| | - Sabrina Haas
- 1. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, D-70550, Stuttgart, Germany
| | | | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University , Tallahassee, Florida 32310, United States
| | - Martin Dressel
- 1. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, D-70550, Stuttgart, Germany
| | - Lapo Bogani
- 1. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, D-70550, Stuttgart, Germany
| | - Frank Neese
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Panayotis Kyritsis
- Laboratory of Inorganic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, Athens, 157 71 Greece
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Mathies G, Chatziefthimiou SD, Maganas D, Sanakis Y, Sottini S, Kyritsis P, Groenen EJJ. High-frequency EPR study of the high-spin FeII complex Fe[(SPPh2)2N]2. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 224:94-100. [PMID: 23064483 DOI: 10.1016/j.jmr.2012.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 06/01/2023]
Abstract
We report continuous-wave electron-paramagnetic-resonance (EPR) spectra of the high-spin Fe(II) complex Fe[(SPPh(2))(2)N](2) at 275.7 GHz, 94.1 GHz and 9.5 GHz. Combined analysis of these EPR spectra shows that the complex occurs in multiple conformations. For two main conformations the spin-Hamiltonian parameters, which reflect the electronic structure of the complex, are accurately determined: (1) D=9.17 cm(-1) (275 GHz), E/D=0.021 and (2) D=8.87 cm(-1) (266 GHz), E/D=0.052. The EPR spectra obtained at 275.7 GHz on single crystals of the complex are essential for the analysis and in addition they reveal that the two main conformations occur at two magnetically distinguishable sites.
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Affiliation(s)
- Guinevere Mathies
- Huygens Laboratory, Department of Molecular Physics, Leiden University, Leiden, The Netherlands
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Eaton SS, Eaton GR. The world as viewed by and with unpaired electrons. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 223:151-63. [PMID: 22975244 PMCID: PMC3496796 DOI: 10.1016/j.jmr.2012.07.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 07/26/2012] [Accepted: 07/27/2012] [Indexed: 06/01/2023]
Abstract
Recent advances in electron paramagnetic resonance (EPR) include capabilities for applications to areas as diverse as archeology, beer shelf life, biological structure, dosimetry, in vivo imaging, molecular magnets, and quantum computing. Enabling technologies include multifrequency continuous wave, pulsed, and rapid scan EPR. Interpretation is enhanced by increasingly powerful computational models.
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Affiliation(s)
- Sandra S Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA
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