1
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Chuchkova L, Bodenstedt S, Picazo-Frutos R, Eills J, Tretiak O, Hu Y, Barskiy DA, de Santis J, Tayler MCD, Budker D, Sheberstov KF. Magnetometer-Detected Nuclear Magnetic Resonance of Photochemically Hyperpolarized Molecules. J Phys Chem Lett 2023:6814-6822. [PMID: 37486855 DOI: 10.1021/acs.jpclett.3c01310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Photochemically induced dynamic nuclear polarization (photo-CIDNP) enables nuclear spin ordering by irradiating samples with light. Polarized spins are conventionally detected via high-field chemical-shift-resolved NMR (above 0.1 T). In this Letter, we demonstrate in situ low-field photo-CIDNP measurements using a magnetically shielded fast-field-cycling NMR setup detecting Larmor precession via atomic magnetometers. For solutions comprising mM concentrations of the photochemically polarized molecules, hyperpolarized 1H magnetization is detected by pulse-acquired NMR spectroscopy. The observed NMR line widths are about 5 times narrower than normally anticipated in high-field NMR and are systematically affected by light irradiation during the acquisition period, reflecting a reduction of the transverse relaxation time constant, T2*, on the order of 10%. Magnetometer-detected photo-CIDNP spectroscopy enables straightforward observation of spin-chemistry processes in the ambient field range from a few nT to tens of mT. Potential applications of this measuring modality are discussed.
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Affiliation(s)
- Liubov Chuchkova
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- Helmholtz-Institut Mainz, GSI Helmholtzzentrum für Schwerionenforschung, 55128 Mainz, Germany
| | - Sven Bodenstedt
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Román Picazo-Frutos
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- Helmholtz-Institut Mainz, GSI Helmholtzzentrum für Schwerionenforschung, 55128 Mainz, Germany
| | - James Eills
- Institute for Bioengineering of Catalonia, 08028 Barcelona, Spain
| | - Oleg Tretiak
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- Helmholtz-Institut Mainz, GSI Helmholtzzentrum für Schwerionenforschung, 55128 Mainz, Germany
| | - Yinan Hu
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- Helmholtz-Institut Mainz, GSI Helmholtzzentrum für Schwerionenforschung, 55128 Mainz, Germany
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Danila A Barskiy
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- Helmholtz-Institut Mainz, GSI Helmholtzzentrum für Schwerionenforschung, 55128 Mainz, Germany
| | - Jacopo de Santis
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Michael C D Tayler
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Dmitry Budker
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- Helmholtz-Institut Mainz, GSI Helmholtzzentrum für Schwerionenforschung, 55128 Mainz, Germany
- Department of Physics, University of California, Berkeley, California 94720-7300, United States
| | - Kirill F Sheberstov
- Institut für Physik, Johannes Gutenberg Universität-Mainz, 55128 Mainz, Germany
- Helmholtz-Institut Mainz, GSI Helmholtzzentrum für Schwerionenforschung, 55128 Mainz, Germany
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2
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Luo J. On the anisotropic weak magnetic field effect in radical-pair reactions. J Chem Phys 2023; 158:234302. [PMID: 37318169 DOI: 10.1063/5.0149644] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/30/2023] [Indexed: 06/16/2023] Open
Abstract
For more than 60 years, scientists have been fascinated by the fact that magnetic fields even weaker than internal hyperfine fields can markedly affect spin-selective radical-pair reactions. This weak magnetic field effect has been found to arise from the removal of degeneracies in the zero-field spin Hamiltonian. Here, I investigated the anisotropic effect of a weak magnetic field on a model radical pair with an axially symmetric hyperfine interaction. I found that S-T± and T0-T± interconversions driven by the smaller x and y-components of the hyperfine interaction can be hindered or enhanced by a weak external magnetic field, depending on its direction. Additional isotropically hyperfine-coupled nuclear spins preserve this conclusion, although the S → T± and T0 → T± transitions become asymmetric. These results are supported by simulating reaction yields of a more biologically plausible, flavin-based radical pair.
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Affiliation(s)
- Jiate Luo
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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3
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Fay TP, Limmer DT. Spin selective charge recombination in chiral donor-bridge-acceptor triads. J Chem Phys 2023; 158:2890465. [PMID: 37184005 DOI: 10.1063/5.0150269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/02/2023] [Indexed: 05/16/2023] Open
Abstract
In this paper, we outline a physically motivated framework for describing spin-selective recombination processes in chiral systems, from which we derive spin-selective reaction operators for recombination reactions of donor-bridge-acceptor molecules, where the electron transfer is mediated by chirality and spin-orbit coupling. In general, the recombination process is selective only for spin-coherence between singlet and triplet states, and it is not, in general, selective for spin polarization. We find that spin polarization selectivity only arises in hopping-mediated electron transfer. We describe how this effective spin-polarization selectivity is a consequence of spin-polarization generated transiently in the intermediate state. The recombination process also augments the coherent spin dynamics of the charge separated state, which is found to have a significant effect on the recombination dynamics and to destroy any long-lived spin polarization. Although we only consider a simple donor-bridge-acceptor system, the framework we present here can be straightforwardly extended to describe spin-selective recombination processes in more complex systems.
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Affiliation(s)
- Thomas P Fay
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - David T Limmer
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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4
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Binhi VN. Statistical Amplification of the Effects of Weak Magnetic Fields in Cellular Translation. Cells 2023; 12:724. [PMID: 36899858 PMCID: PMC10000676 DOI: 10.3390/cells12050724] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/12/2023] Open
Abstract
We assume that the enzymatic processes of recognition of amino acids and their addition to the synthesized molecule in cellular translation include the formation of intermediate pairs of radicals with spin-correlated electrons. The mathematical model presented describes the changes in the probability of incorrectly synthesized molecules in response to a change in the external weak magnetic field. A relatively high chance of errors has been shown to arise from the statistical enhancement of the low probability of local incorporation errors. This statistical mechanism does not require a long thermal relaxation time of electron spins of about 1 μs-a conjecture often used to match theoretical models of magnetoreception with experiments. The statistical mechanism allows for experimental verification by testing the usual Radical Pair Mechanism properties. In addition, this mechanism localizes the site where magnetic effects originate, the ribosome, which makes it possible to verify it by biochemical methods. This mechanism predicts a random nature of the nonspecific effects caused by weak and hypomagnetic fields and agrees with the diversity of biological responses to a weak magnetic field.
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Affiliation(s)
- Vladimir N Binhi
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov St., 119991 Moscow, Russia
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5
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Konowalczyk M, Foster Vander Elst O, Storey JG. Development of lock-in based overtone modulated MARY spectroscopy for detection of weak magnetic field effects. Phys Chem Chem Phys 2021; 23:1273-1284. [PMID: 33355552 DOI: 10.1039/d0cp04814c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Modulated magnetically altered reaction yield (ModMARY) spectroscopy is a derivative variant of fluorescence detected magnetic field effect measurement, where the applied magnetic field has both a constant and a modulated component. As in many derivative spectroscopy techniques, the signal to noise ratio scales with the magnitude of the modulation. High modulation amplitudes, however, distort the signal and can obscure small features of the measured spectrum. In order to detect weak magnetic field effects (including the low field effect) a balance of the two has to be found. In this work we look in depth at the origin of the distortion of the MARY signal by field modulation. We then present an overtone detection scheme, as well as a data analysis method which allows for correct fitting of both harmonic and overtone signals of the modulation broadened MARY data. This allows us to robustly reconstruct the underlying MARY curve at different modulation depths. To illustrate the usefulness of the technique, we show measurements and analysis of a well known magnetosensitive system of pyrene/1,3-dicyanobenzene (Py/DCB). The measurements of first (h1) and second (h2) harmonic spectra are performed at different modulation depths for both natural isotopic abundance (PyH10), and perdeuterated (PyD10) pyrene samples.
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Affiliation(s)
- Marcin Konowalczyk
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford OX1 3QZ, UK. and Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford OX1 3QR, UK
| | | | - Jonathan G Storey
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford OX1 3QR, UK
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6
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Ivanov KL, Lukzen NN. Multiplet-to-net CIDEP conversion by MW-pulses with adiabatically ramped amplitude. Mol Phys 2019. [DOI: 10.1080/00268976.2018.1562121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Konstantin L. Ivanov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Nikita N. Lukzen
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
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7
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Vallejo D, Hidalgo MA, Hernández JM. Effects of long-term exposure to an extremely low frequency magnetic field (15 µT) on selected blood coagulation variables in OF1 mice. Electromagn Biol Med 2019; 38:279-286. [PMID: 31303067 DOI: 10.1080/15368378.2019.1641719] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The long-term exposure of OF1 mice to an extremely low frequency magnetic field (ELF-MF; 50 Hz, 15 µT [rms]) has been associated with the appearance of leukaemia. Neoplasms are usually accompanied by changes in haemostatic processes but reports on changes in blood coagulation following exposure to an ELF-MF are scarce and rather fragmentary. The aim of the present work was to determine whether any global or partial coagulation variables are modified after such long-term exposure. A parental generation of six week-old OF1 mice was exposed to an artificial ELF-MF for 14 weeks. Mating was then allowed, and the resulting filial generation raised until the age of 31-35 weeks within the same ELF-MF. Control animals were subjected only to the magnetic field of the Earth. Whole blood samples were extracted from the anesthetised filial generation of mice by cardiac puncture. White blood cells (WBC) were counted, the activated partial thromboplastin time (APTT) and prothrombin time (PT) determined, and plasma fibrinogen, reptilase time (RT), and factor VIII activity examined. The similarity between the results for the present control animals and those recorded in the literature for human blood render OF1 mice a suitable study model. The differences in the studied coagulation variables were largely owed simply to sex. However, the females showed a very significant shortening of the PT time associated with ELF-MF exposure. Exposure also caused significant increases in the female APTT and RT values, and in general reduced the differences between the sexes.
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Affiliation(s)
- D Vallejo
- Department of Biology of Systems, University of Alcalá , Alcalá de Henares , Spain
| | - M A Hidalgo
- Department of Physics and Mathematics, University of Alcalá , Alcalá de Henares , Spain
| | - J M Hernández
- Department of Biology of Systems, University of Alcalá , Alcalá de Henares , Spain
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8
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Lewis AM, Fay TP, Manolopoulos DE, Kerpal C, Richert S, Timmel CR. On the low magnetic field effect in radical pair reactions. J Chem Phys 2018; 149:034103. [PMID: 30037236 DOI: 10.1063/1.5038558] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Radical pair recombination reactions are known to be sensitive to the application of both low and high magnetic fields. The application of a weak magnetic field reduces the singlet yield of a singlet-born radical pair, whereas the application of a strong magnetic field increases the singlet yield. The high field effect arises from energy conservation: when the magnetic field is stronger than the sum of the hyperfine fields in the two radicals, S → T± transitions become energetically forbidden, thereby reducing the number of pathways for singlet to triplet interconversion. The low field effect arises from symmetry breaking: the application of a weak magnetic field lifts degeneracies among the zero field eigenstates and increases the number of pathways for singlet to triplet interconversion. However, the details of this effect are more subtle and have not previously been properly explained. Here we present a complete analysis of the low field effect in a radical pair containing a single proton and in a radical pair in which one of the radicals contains a large number of hyperfine-coupled nuclear spins. We find that the new transitions that occur when the field is switched on are between S and T0 in both cases, and not between S and T± as has previously been claimed. We then illustrate this result by using it in conjunction with semiclassical spin dynamics simulations to account for the observation of a biphasic-triphasic-biphasic transition with increasing magnetic field strength in the magnetic field effect on the time-dependent survival probability of a photoexcited carotenoid-porphyrin-fullerene radical pair.
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Affiliation(s)
- Alan M Lewis
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Thomas P Fay
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - David E Manolopoulos
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Christian Kerpal
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Sabine Richert
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Christiane R Timmel
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
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9
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Ivanov KL, Wagenpfahl A, Deibel C, Matysik J. Spin-chemistry concepts for spintronics scientists. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:1427-1445. [PMID: 28900597 PMCID: PMC5530719 DOI: 10.3762/bjnano.8.143] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/13/2017] [Indexed: 05/03/2023]
Abstract
Spin chemistry and spintronics developed independently and with different terminology. Until now, the interaction between the two fields has been very limited. In this review, we compile the two "languages" in an effort to enhance communication. We expect that knowledge of spin chemistry will accelerate progress in spintronics.
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Affiliation(s)
- Konstantin L Ivanov
- International Tomography Center, Siberian Branch of Russian Academy of Science, Institutskaya 3а, Novosibirsk, 630090 Russia
- Novosibirsk State University, Institutskaya 3а, Novosibirsk, 630090 Russia
| | | | - Carsten Deibel
- Institut für Physik, Technische Universität Chemnitz, 09126 Chemnitz, Germany
| | - Jörg Matysik
- Universität Leipzig, Institut für Analytische Chemie, Linnéstr. 3, D-04103 Leipzig, Germany
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10
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Manolopoulos DE, Hore PJ. An improved semiclassical theory of radical pair recombination reactions. J Chem Phys 2013; 139:124106. [DOI: 10.1063/1.4821817] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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11
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Selective quenching of magnetic field effect for radical ion pairs with widely different hyperfine couplings. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.05.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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12
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Sergey N, Verkhovlyuk V, Kalneus E, Korolev V, Melnikov A, Burdukov A, Stass D, Molin YN. Registration of radical anions of Al, Ga, In tris-8-oxyquinolinates by magnetosensitive and spectrally resolved recombination luminescence in benzene solutions. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.08.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Sacher M, Grampp G. Magnetic field effects on the luminescence of p-phenylenediamine derivatives. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19971010613] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Matveeva AG, Sviridenko FB, Korolev VV, Kuibida LV, Stass DV, Shundrin LA, Reznikov VA, Grampp GG. Difficulties in building radiation-generated three-spin systems using spin-labeled luminophores. J Phys Chem A 2008; 112:183-93. [PMID: 18088106 DOI: 10.1021/jp076835e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatic compounds are well-known acceptors of primary radical ions that are formed under high-energy irradiation of nonpolar systems. Thus formed radical ion pairs recombine and produce magnetosensitive fluorescence, which helps study the short-lived radical ions. It was initially suggested that a simple introduction of a spin label into the original arene would allow an easy transition from two-spin to three-spin systems, retaining the experimental techniques available for radical pairs. However, it turned out that spin-labeled arenes often do not produce magnetosensitive fluorescence in the conditions of a conventional radiochemical experiment. To understand the effect of the introduced spin label, we synthesized a series of compounds with the general structure "stable 3-imidazoline radical-two-carbon bridge-naphthalene" as well as their diamagnetic analogues. By use of this set of acceptors, we determined the processes that ruin the observed signal and established their connection with the chemical structure of the compound. We found that the compounds with flexible (saturated) two-carbon bridges between the luminophore and the stable radical moieties exist in solution in folded conformation, which leads to suppression of luminescence from naphthalene due to efficient through-space exchange quenching of the excited state by the radical. Increasing the rigidity of the bridge by introducing the double bond drastically increases the reactivity of the extended pi-system. In these compounds, the energy released upon recombination is spent in radiationless processes of chemical transformations both at the stage of the radical ion and at the stage of the electronically excited molecule.
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Affiliation(s)
- Anna G Matveeva
- Institute of Chemical Kinetics and Combustion SB RAS, ul. Institutskaya, 3, 630090 Novosibirsk, Russia
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15
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Jones AR, Hay S, Woodward JR, Scrutton NS. Magnetic field effect studies indicate reduced geminate recombination of the radical pair in substrate-bound adenosylcobalamin-dependent ethanolamine ammonia lyase. J Am Chem Soc 2007; 129:15718-27. [PMID: 18041840 DOI: 10.1021/ja077124x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The apparent conflict between literature evidence for (i) radical pair (RP) stabilization in adenosylcobalamin (AdoCbl)-dependent enzymes and (ii) the manifestation of magnetic field sensitivity due to appreciable geminate recombination of the RP has been reconciled by pre-steady-state magnetic field effect (MFE) investigations with ethanolamine ammonia lyase (EAL). We have shown previous stopped-flow MFE studies to be insensitive to magnetically induced changes in the net forward rate of C-Co homolytic bond cleavage. Subsequently, we observed a magnetic-dependence in the continuous-wave C-Co photolysis of free AdoCbl in 75% glycerol but have not done so in the thermal homolysis of this bond in the enzyme-bound cofactor in the presence of substrate. Consequently, in the enzyme-bound state, the RP generated upon homolysis appears to be stabilized against the extent of geminate recombination required to observe an MFE. These findings have strong implications for the mechanism of RP stabilization and the unprecedented catalytic power of this important class of cobalamin-dependent enzymes.
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Affiliation(s)
- Alex R Jones
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
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Miura T, Maeda K, Arai T. The spin mixing process of a radical pair in low magnetic field observed by transient absorption detected nanosecond pulsed magnetic field effect. J Phys Chem A 2007; 110:4151-6. [PMID: 16553365 DOI: 10.1021/jp056488d] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The spin mixing process of the radical pair in the sodium dodecyl sulfate (SDS) micelle is studied by using a novel technique nanosecond pulsed magnetic field effect on transient absorption. We have developed the equipment for a nanosecond pulsed magnetic field and observed its effect on the radical pair reaction. A decrease of the free radical yield by a reversely directed pulsed magnetic field that cancels static field is observed, and the dependence on its magnitude, which is called pulsed MARY (magnetic field effect on reaction yield) spectra, is studied. The observed spectra reflect the spin mixing in 50-200 ns and show clear time evolution. Theoretical simulation of pulsed MARY spectra based on a single site modified Liouville equation indicates that the fast spin dephasing processes induced by the modulation of electron-electron spin interaction by molecular reencounter affect to the coherent spin mixing by a hyperfine interaction in a low magnetic field.
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Affiliation(s)
- Tomoaki Miura
- Department of Chemistry, Faculty of Science, Shizuoka University, Ohya 836, Shizuoka City 422-8529, Japan
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17
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McLauchlan K, Nattrass S. Experimental studies of the spin-correlated radical pair in micellar and microemulsion media; MARY, RYDMRB0and RYDMRB1spectra. Mol Phys 2006. [DOI: 10.1080/00268978800101941] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Kalneus EV, Stass DV, Ivanov KL, Molin YN. A MARY study of radical anions of fluorinated benzenes. Mol Phys 2006. [DOI: 10.1080/00268970600635438] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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19
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Henbest KB, Athanassiades E, Maeda K, Kuprov I, Hore PJ, Timmel CR. Photoionization of TMPD in DMSO solution: mechanism and magnetic field effects. Mol Phys 2006. [DOI: 10.1080/00268970600611017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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20
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Verkhovlyuk VN, Morozov VA, Stass DV, Doktorov AB, Molin YUN. Experimental and theoretical study of spin evolution ‘switching on’ of the radical ion pair in MARY spectroscopy. Mol Phys 2006. [DOI: 10.1080/00268970600616313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Henbest K, Maeda K, Athanassiades E, Hore P, Timmel C. Measurement of magnetic field effects on radical recombination reactions using triplet–triplet energy transfer. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.01.106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Suzuki T, Miura T, Maeda K, Arai T. Spin Dynamics of the Radical Pair in a Low Magnetic Field Studied by the Transient Absorption Detected Magnetic Field Effect on the Reaction Yield and Switched External Magnetic Field. J Phys Chem A 2005; 109:9911-8. [PMID: 16838907 DOI: 10.1021/jp053989q] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The spin dynamics of the radical pair generated from the photocleavage reaction of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TMDPO) in micellar solutions was studied by the time-resolved magnetic field effect (MFE) on the transient absorption (TA) and by a novel technique, absorption detected switched external magnetic field (AD-SEMF). Thanks to the large hyperfine coupling constant (A = 38 mT), a characteristic negative MFE on the radical yield was observed at a magnetic field lower than 60 mT whereas a positive effect due to the conventional hyperfine (HFM) and relaxation mechanisms (RM) was observed at higher magnetic field. The negative effect can be assigned to the mechanism "so-called" low field effect (LFE) mechanism and has been analyzed thoroughly using a model calculation incorporating a fast spin dephasing process. The time scale of the spin mixing process of LFE studied by AD-SEMF is shorter than the lifetime of the recombination kinetics of the radical pair. These results indicate that the LFE originates from the coherent spin motion. This can be interfered from the fast spin dephasing caused by electron spin interaction fluctuations.
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Affiliation(s)
- Toshiaki Suzuki
- Department of Chemistry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan
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23
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Justinek M, Grampp G, Landgraf S, Hore PJ, Lukzen NN. Electron Self-Exchange Kinetics Determined by MARY Spectroscopy: Theory and Experiment. J Am Chem Soc 2004; 126:5635-46. [PMID: 15113235 DOI: 10.1021/ja0394784] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electron self-exchange between a neutral molecule and its charged radical, which is part of a spin-correlated radical ion pair, gives rise to line width effects in the fluorescence-detected MARY (magnetic field effect on reaction yield) spectrum similar to those observed in EPR spectroscopy. An increasing self-exchange rate (i.e., a higher concentration of the neutral molecule) leads to broadening and subsequent narrowing of the spectrum. Along with a series of MARY spectra recorded for several systems (the fluorophores pyrene, pyrene-d(10) and N-methylcarbazole in combination with 1,2- and 1,4-dicyanobenzene) in various solvents, a theoretical model is developed that describes the spin evolution and the diffusive recombination of the radical pair under the influence of the external magnetic field and electron self-exchange, thereby allowing the simulation of MARY spectra of the systems investigated experimentally. The spin evolution of the radicals in the pair is calculated separately using spin correlation tensors, thereby allowing rigorous quantum mechanical calculations for real spin systems. It is shown that the combination of these simulations with high resolution, low noise experimental spectra makes the MARY technique a novel, quantitative method for the determination of self-exchange rate constants. In comparison to a simple analytical formula which estimates the self-exchange rate constant from the slope of the linear part of a line width vs concentration plot, the simulation method yields more reliable and accurate results. The correctness of the results obtained by the MARY method is proved by a comparison with corresponding data from the well-established EPR line broadening technique. With its less stringent restrictions on radical lifetime and stability, the MARY technique provides an alternative to the classical EPR method, in particular for systems involving short-lived and unstable radicals.
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Affiliation(s)
- M Justinek
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Technikerstrasse 4/I, A-8010 Graz, Austria
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Verkhovlyuk V, Morozov V, Stass D, Doktorov A, Molin Y. Experimental and theoretical study of spin evolution ‘freezing’ of the radical ion pair in MARY spectroscopy. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(03)01321-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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SVIRIDENKO FB, STASS DV, MOLIN YUN. Study of interaction of aliphatic alcohols with primary radical cations ofn-alkanes using MARY spectroscopy. Mol Phys 2003. [DOI: 10.1080/0026897031000099943] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Sabo J, Mirossay L, Horovcak L, Sarissky M, Mirossay A, Mojzis J. Effects of static magnetic field on human leukemic cell line HL-60. Bioelectrochemistry 2002; 56:227-31. [PMID: 12009481 DOI: 10.1016/s1567-5394(02)00027-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A number of structures with magnetic moments exists in living organisms that may be oriented by magnetic field. While most experimental efforts belong to the area of effects induced by weak and extremely low-frequency electromagnetic fields, we attempt to give an attention to the biological effects of strong static magnetic fields. The influence of static magnetic field (SMF) on metabolic activity of cells was examined. The metabolic activity retardation is observed in human leukemic cell line HL-60 exposed to 1-T SMF for 72 h. The retardation effect was observed as well as in the presence of the mixture of the antineoplastic drugs 5 fluorouracil, cisplatin, doxorubicin and vincristine.
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Affiliation(s)
- J Sabo
- Department of Medical Biophysics, Medical Faculty, P.J. Safarik University, Trieda SNP 1, 04011 Kosice, Slovak Republic.
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Justinek M, Grampp G, Landgraf S. Determination of electron self-exchange rate constants with MARY spectroscopy: Dependence on the fluorophore. Phys Chem Chem Phys 2002. [DOI: 10.1039/b205606b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bentsman J, Dardynskaya IV, Shadyro O, Pellegrinetti G, Blauwkamp R, Gloushonok G. Mathematical modeling and stochastic H(infinity) identification of the dynamics of the MF-influenced oxidation of hexane. Math Biosci 2001; 169:129-51. [PMID: 11166319 DOI: 10.1016/s0025-5564(00)00057-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This paper presents a mathematical model explicitly reflecting the magnetic-field-induced transitions in a biologically significant process: n-hexane oxidation. The range of the magnetic field strength is found (0.05-0.3 T) with the trend indicating significant magnetic-field-induced change in the rates of reactions involving hexane (up to 50% at 0.2 T). The equations describing the effects of the magnetic field on the photoinduced free radical reaction of oxidation involving a lipid-modeling substance, hexane, are obtained on the basis of chemical kinetics and data from a batch experiment. The magnetic-field-induced changes in n-hexane oxidation are validated using the identification technique based on the real time input-output data in a separately conducted flow-through experiment.
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Affiliation(s)
- J Bentsman
- Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801, USA.
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Stass D, Woodward J, Timmel C, Hore P, McLauchlan K. Radiofrequency magnetic field effects on chemical reaction yields. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00980-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Timmel C, Till U, Brocklehurst B, Mclauchlan K, Hore P. Effects of weak magnetic fields on free radical recombination reactions. Mol Phys 1998. [DOI: 10.1080/00268979809483134] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
Electrification in developed countries has progressively increased the mean level of extremely low-frequency electromagnetic fields (ELF-EMFs) to which populations are exposed; these humanmade fields are substantially above the naturally occurring ambient electric and magnetic fields of approximately 10(-4) Vm(-1) and approximately 10(-13) T, respectively. Several epidemiological studies have concluded that ELF-EMFs may be linked to an increased risk of cancer, particularly childhood leukemia. These observations have been reinforced by cellular studies reporting EMF-induced effects on biological systems, most notably on the activity of components of the pathways that regulate cell proliferation. However, the limited number of attempts to directly replicate these experimental findings have been almost uniformly unsuccessful, and no EMF-induced biological response has yet been replicated in independent laboratories. Many of the most well-defined effects have come from gene expression studies; several attempts have been made recently to repeat these key findings. This review analyses these studies and summarizes other reports of major cellular responses to EMFs and the published attempts at replication. The opening sections discuss quantitative aspects of exposure to EMFs and the incidence of cancers that have been correlated with such fields. The concluding section considers the problems that confront research in this area and suggests feasible strategies.
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Affiliation(s)
- A Lacy-Hulbert
- Department of Biochemistry, University of Cambridge, England.
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Woodward J, Jackson R, Timmel C, Hore P, McLauchlan K. Resonant radiofrequency magnetic field effects on a chemical reaction. Chem Phys Lett 1997. [DOI: 10.1016/s0009-2614(97)00542-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Stass D, Lukzen N, Tadjikov B, Molin Y. Manifestation of quantum coherence upon recombination of radical ion pairs in weak magnetic fields. Systems with non-equivalent nuclei. Chem Phys Lett 1995. [DOI: 10.1016/0009-2614(94)01489-i] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Batchelor S, McLauchlan K, Shkrob I. Reaction yield detected magnetic resonance and magnetic field effect studies of radical pairs containing electronically excited organic radicals. Mol Phys 1992. [DOI: 10.1080/00268979200102331] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Electron spin exchange in micellized radical pairs. III. 13C low-field ratio frequency stimulated nuclear polarization spectroscopy (LF SNP). Chem Phys 1992. [DOI: 10.1016/0301-0104(92)80233-l] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Batchelor S, Heikkilä H, Kay C, McLauchlan K, Shkrob I. Chemically induced dynamic electron polarization (CIDEP) in systems involving radical-ion pairs generated from singlet exciplexes; observation of positive electron exchange interactions. Chem Phys 1992. [DOI: 10.1016/0301-0104(92)80218-k] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Extrapolation of quantitative measurements across biological systems requires knowledge of field-organism interaction mechanisms. In the absence of such knowledge, one can only indicate which parameters would be important under some plausible assumptions that still lack experimental proof. In the first part of the paper it is assumed that biological effects of low intensity, extremely low frequency magnetic fields are caused by the electric fields which they induce. It is shown that detailed knowledge of electrical properties on a microscale is important to predict effects that may be due to local current density, electric field strength, surface charge distribution, and mechanical forces. In the second part of the paper, it is shown that all proposed mechanisms for direct interaction between alternating magnetic fields and cells involve also the magnitude and direction of a simultaneously present static magnetic field. Reviewed are "cyclotron resonance," quantum mechanical effects on ions weakly bound to proteins, nuclear magnetic resonance, and recent progress in magneto chemistry dealing with effects of magnetic fields of a few hundred microtesla on chemical reactions that involve free radicals.
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Affiliation(s)
- C Polk
- Department of Electrical Engineering, University of Rhode Island, Kingston 02881
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Hamilton C, McLauchlan K, Peterson K. J-resonances in MARY and RYDMR spectra from freely diffusing radical ion pairs. Chem Phys Lett 1989. [DOI: 10.1016/0009-2614(89)85083-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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