1
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Luo J. Sensitivity enhancement of radical-pair magnetoreceptors as a result of spin decoherence. J Chem Phys 2024; 160:074306. [PMID: 38380753 DOI: 10.1063/5.0182172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
Electron spin relaxation is, on many occasions, considered an elephant in the room that challenges the idea of a radical-pair compass, a leading hypothesis for the navigation of migratory avian species. It has been widely recognized that an effective radical-pair magnetoreceptor requires a relaxation time that is long enough for an external magnetic field as weak as the geomagnetic field to significantly modify the coherent spin dynamics. However, previous studies proposed that certain spin relaxation, far quicker than the radical recombination reactions, could enhance, rather than degrade, the directional sensitivity of a radical-pair magnetoreceptor. Here, I investigate relaxation effects on the singlet-triplet interconversion of a model radical pair and find that the enhancement effect originates from population relaxation over a period of several microseconds as a result of efficient spin decoherence. Insights into the truncated spin systems shed light on the physics behind them. I further investigate the possibilities of such enhancement in cryptochrome-based magnetoreception, in which electron hopping takes place between tryptophan residues.
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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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2
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Golesworthy MJ, Zollitsch T, Luo J, Selby D, Jarocha LE, Henbest KB, Paré-Labrosse O, Bartölke R, Schmidt J, Xu J, Mouritsen H, Hore PJ, Timmel CR, Mackenzie SR. Singlet-triplet dephasing in radical pairs in avian cryptochromes leads to time-dependent magnetic field effects. J Chem Phys 2023; 159:105102. [PMID: 37694754 DOI: 10.1063/5.0166675] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 08/21/2023] [Indexed: 09/12/2023] Open
Abstract
Cryptochrome 4a (Cry4a) has been proposed as the sensor at the heart of the magnetic compass in migratory songbirds. Blue-light excitation of this protein produces magnetically sensitive flavin-tryptophan radical pairs whose properties suggest that Cry4a could indeed be suitable as a magnetoreceptor. Here, we use cavity ring-down spectroscopy to measure magnetic field effects on the kinetics of these radical pairs in modified Cry4a proteins from the migratory European robin and from nonmigratory pigeon and chicken. B1/2, a parameter that characterizes the magnetic field-dependence of the reactions, was found to be larger than expected on the basis of hyperfine interactions and to increase with the delay between pump and probe laser pulses. Semiclassical spin dynamics simulations show that this behavior is consistent with a singlet-triplet dephasing (STD) relaxation mechanism. Analysis of the experimental data gives dephasing rate constants, rSTD, in the range 3-6 × 107 s-1. A simple "toy" model due to Maeda, Miura, and Arai [Mol. Phys. 104, 1779-1788 (2006)] is used to shed light on the origin of the time-dependence and the nature of the STD mechanism. Under the conditions of the experiments, STD results in an exponential approach to spin equilibrium at a rate considerably slower than rSTD. We attribute the loss of singlet-triplet coherence to electron hopping between the second and third tryptophans of the electron transfer chain and comment on whether this process could explain differences in the magnetic sensitivity of robin, chicken, and pigeon Cry4a's.
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Affiliation(s)
| | - Tilo Zollitsch
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Jiate Luo
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Dan Selby
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Lauren E Jarocha
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, USA
| | - Kevin B Henbest
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | | | - Rabea Bartölke
- AG Neurosensory Sciences/Animal Navigation, Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Jessica Schmidt
- AG Neurosensory Sciences/Animal Navigation, Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Jingjing Xu
- AG Neurosensory Sciences/Animal Navigation, Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- AG Neurosensory Sciences/Animal Navigation, Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - P J Hore
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
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3
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Oka Y, Miura T, Ikoma T. Photogenerated Radical Pair between Flavin and a Tryptophan-Containing Transmembrane-Type Peptide in a Large Unilamellar Vesicle. J Phys Chem B 2021; 125:4057-4066. [PMID: 33858138 DOI: 10.1021/acs.jpcb.1c01231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electron-transfer (ET) reactions in biological systems, such as those with magnetic sensors based on flavoproteins and electron transport at biomembrane interfaces, are interesting and important issues that require understanding. As a model system of flavoproteins in biomimetic environments, we report the dynamics of the radical pair generated by photoinduced ET between riboflavin tetrabutylate (RFTB) and tryptophan (Trp) residues in a transmembrane-type polypeptide, both of which are distributed in a large unilamellar vesicle of 1,2-dimyristoyl-sn-glycero-3-phosphocholine. The Trp residues locate near the hydrophilic membrane interface, as confirmed by a dual-fluorescence quenching assay. The fluorescence and transient absorption upon photoexcitation of RFTB indicate that ET from both the singlet and triplet excited states occurs at the hydrophilic interface, whereas the RFTB in the hydrophobic region does not contribute to ET. The ET efficiency and the magnetic field effect (MFE) on the RFTB anion increase significantly above the gel-to-liquid crystal phase transition temperature due to a decrease in microviscosity. The MFE analysis indicates that the radical pair generated from the triplet ET channel exhibits a long lifetime as those in micellar systems due to the strong cage effect of the vesicle.
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Affiliation(s)
- Yoshimi Oka
- Frontier Research Core for Life Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Tomoaki Miura
- Department of Chemistry, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Tadaaki Ikoma
- Department of Chemistry, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
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4
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Player TC, Hore PJ. Source of magnetic field effects on the electrocatalytic reduction of CO2. J Chem Phys 2020; 153:084303. [DOI: 10.1063/5.0021643] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thomas C. Player
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, United Kingdom
| | - P. J. Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, United Kingdom
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5
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Mims D, Schmiedel A, Holzapfel M, Lukzen NN, Lambert C, Steiner UE. Magnetic field effects in rigidly linked D-A dyads: Extreme on-resonance quantum coherence effect on charge recombination. J Chem Phys 2019; 151:244308. [DOI: 10.1063/1.5131056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- David Mims
- Institute of Organic Chemistry, University of Würzburg, Am Hubland 1, Würzburg, Germany
| | - Alexander Schmiedel
- Institute of Organic Chemistry, University of Würzburg, Am Hubland 1, Würzburg, Germany
| | - Marco Holzapfel
- Institute of Organic Chemistry, University of Würzburg, Am Hubland 1, Würzburg, Germany
| | - Nikita N. Lukzen
- International Tomography Center, Institutskaya 3a, Novosibirsk, Russia and Novosibirsk State University, Novosibirsk 630090, Russia
| | - Christoph Lambert
- Institute of Organic Chemistry, University of Würzburg, Am Hubland 1, Würzburg, Germany
| | - Ulrich E. Steiner
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, Konstanz, Germany
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6
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Sakurai M, Kobori Y, Tachikawa T. Structural Dynamics of Lipid Bilayer Membranes Explored by Magnetic Field Effect Based Fluorescence Microscopy. J Phys Chem B 2019; 123:10896-10902. [PMID: 31769688 DOI: 10.1021/acs.jpcb.9b09782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipid bilayer membranes are known to exist as heterogeneous and dynamic structures where the molecules are always moving and fluctuating under physiological conditions. Magnetic field effects (MFEs) studied herein are phenomena in which the exciplex emission from an electron donor-acceptor dyad increases or decreases by applying an external magnetic field. The characteristic dependence of MFEs on the viscosity and polarity of the surrounding medium has been applied to investigate the local environments around the probe molecule. In this study, a novel MFE-based fluorescence microscopy technique was developed to explore the structural dynamics of lipid bilayer membranes. The vesicle formation during the membrane deformation was selectively visualized through the MFEs, thus allowing the extraction of information on the cellular dynamics at high temporal and spatial resolutions. This highly versatile and powerful technique is applicable to a wide range of areas, such as biology and material science.
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7
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Maeda K, Naito Y. Dynamics of flavin containing radical pairs in SDS micellar media probed by static and pulse magnetic field effect and pulse ADMR. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1580779] [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)
- Kiminori Maeda
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Yusuke Naito
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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8
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Miura T. Studies on coherent and incoherent spin dynamics that control the magnetic field effect on photogenerated radical pairs. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1643510] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Tomoaki Miura
- Department of Science, Niigata University, Niigata, Japan
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9
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Fay TP, Manolopoulos DE. Radical pair intersystem crossing: Quantum dynamics or incoherent kinetics? J Chem Phys 2019; 150:151102. [DOI: 10.1063/1.5095204] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thomas P. Fay
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - David E. Manolopoulos
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
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10
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Miura T, Maeda K, Oka Y, Ikoma T. Gigantic Magnetic Field Effect on the Long-Lived Intermolecular Charge-Separated State Created at the Nonionic Bilayer Membrane. J Phys Chem B 2018; 122:12173-12183. [PMID: 30444615 DOI: 10.1021/acs.jpcb.8b08389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For realization of low-cost organic photon-energy conversion, the supramolecular approach has been a focus of attention as a counter approach to precise synthesis of covalently linked donor (D)-acceptor (A) molecules. Here we report photogeneration of a long-lived (∼3 μs) intermolecular charge-separated (CS) state of metal porphyrins (D) and an alkyl viologen (A) at an interface of a vesicle membrane formed by self-assembly of nonionic surfactant and cholesterol molecules. The yield of escaped free radicals is negligibly low as in the case of CS states in covalently linked D-A systems. Furthermore, the transient concentration of the CS state dramatically increases by ∼100% upon application of a magnetic field of 250 mT at room temperature. The simulation of the spin dynamics of the CS state indicates that fast (∼107 s-1) spin-selective recombination and slow (105-106 s-1) dissociation-re-encounter dynamics are the key processes for the long CS-state lifetime and the gigantic magnetic field effect. It has turned out that such dynamics are sharply dependent on temperature and alkyl chain length of the viologen. The present results would lead to the development of future materials for light energy conversion, drug delivery, and microscopic bioprobes.
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Affiliation(s)
- Tomoaki Miura
- Department of Chemistry , Niigata University , 2-8050 Ikarashi, Nishi-ku , Niigata 950-2181 , Japan
| | - Kiminori Maeda
- Department of Chemistry, Graduate School of Science and Engineering , Saitama University , 255 Shimo-okubo, Sakura-ku , Saitama 338-8570 , Japan
| | - Yoshimi Oka
- Frontier Research Core for Life Sciences , University of Toyama , 2630 Sugitani , Toyama 930-0194 , Japan
| | - Tadaaki Ikoma
- Department of Chemistry , Niigata University , 2-8050 Ikarashi, Nishi-ku , Niigata 950-2181 , Japan.,Center for Coordination of Research Facilities , Niigata University , 2-8050 Ikarashi, Nishi-ku , Niigata 950-2181 , Japan
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11
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Worster SB, Hore PJ. Proposal to use superparamagnetic nanoparticles to test the role of cryptochrome in magnetoreception. J R Soc Interface 2018; 15:20180587. [PMID: 30381345 PMCID: PMC6228473 DOI: 10.1098/rsif.2018.0587] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/08/2018] [Indexed: 11/12/2022] Open
Abstract
Evidence is accumulating to support the hypothesis that some animals use light-induced radical pairs to detect the direction of the Earth's magnetic field. Cryptochrome proteins seem to be involved in the sensory pathway but it is not yet clear if they are the magnetic sensors: they could, instead, play a non-magnetic role as signal transducers downstream of the primary sensor. Here we propose an experiment with the potential to distinguish these functions. The principle is to use superparamagnetic nanoparticles to disable any magnetic sensing role by enhancing the electron spin relaxation of the radicals so as to destroy their spin correlation. We use spin dynamics simulations to show that magnetoferritin, a synthetic, protein-based nanoparticle, has the required properties. If cryptochrome is the primary sensor, then it should be inactivated by a magnetoferritin particle placed 12-16 nm away. This would prevent a bird from using its magnetic compass in behavioural tests and abolish magnetically sensitive neuronal firing in the retina. The key advantage of such an experiment is that any signal transduction role should be completely unaffected by the tiny magnetic interactions (≪kBT) required to enhance the spin relaxation of the radical pair.
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Affiliation(s)
- Susannah Bourne Worster
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK
| | - P J Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK
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12
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Wu Y, Zhou J, Nelson JN, Young RM, Krzyaniak MD, Wasielewski MR. Covalent Radical Pairs as Spin Qubits: Influence of Rapid Electron Motion between Two Equivalent Sites on Spin Coherence. J Am Chem Soc 2018; 140:13011-13021. [DOI: 10.1021/jacs.8b08105] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yilei Wu
- Department of Chemistry and Institute for Sustainability and Energy, Northwestern Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Jiawang Zhou
- Department of Chemistry and Institute for Sustainability and Energy, Northwestern Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Jordan N. Nelson
- Department of Chemistry and Institute for Sustainability and Energy, Northwestern Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Ryan M. Young
- Department of Chemistry and Institute for Sustainability and Energy, Northwestern Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Matthew D. Krzyaniak
- Department of Chemistry and Institute for Sustainability and Energy, Northwestern Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy, Northwestern Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
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13
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Hoang HM, Pham VTB, Grampp G, Kattnig DR. Magnetic Field-Sensitive Radical Pair Dynamics in Polymethylene Ether-Bridged Donor-Acceptor Systems. ACS OMEGA 2018; 3:10296-10305. [PMID: 30198006 PMCID: PMC6120740 DOI: 10.1021/acsomega.8b01232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/20/2018] [Indexed: 05/13/2023]
Abstract
Donor-acceptor systems forming exciplexes are versatile models for the study of magnetic field effects (MFEs) on charge recombination reactions. The MFEs originate from singlet-triplet interconversion within transient radical ion pairs (RIPs), which exist in a dynamic equilibrium with the exciplexes. Here, we describe the synthesis and MFEs of the chain-linked N,N-dimethylaniline (DMA)/9-methylanthracene (MAnt) donor-acceptor system MAnt-(CH2) n -O-CH2-CH2-DMA for n = 6, 8, 10, and 16. The MFEs are found to increase with increasing chain length. Effects as large as 37.5% have been observed for the long-chain compound with n = 16. The solvent dependence of the MFEs at magnetic field intensity 75 mT is reported. For the range of solvent static dielectric constants εs = 6.0-36.0, the MFEs go through a maximum for intermediate polarities, for which the direct formation of RIPs prevails and their dissociation and reencounter are balanced. Field-resolved measurements (MARY spectra) are reported for solutions in butyronitrile. The MARY spectra reveal that for n = 8, 10, 16, the average exchange interaction is negligible during the coherent lifetime of the radical pair. However, singlet-triplet dephasing broadens the lineshape; the shorter the linker, the more pronounced this effect is. For n = 6, a dip in the fluorescence intensity reveals a nonzero average exchange coupling of the order of ±5 mT. We discuss the field-dependence in the framework of the semiclassical theory taking spin-selective recombination, singlet-triplet dephasing, and exchange coupling into account. Singlet recombination rates of the order of 0.1 ns-1 and various degrees of singlet-triplet dephasing govern the spin dynamics. In addition, because of a small free energy gap between the exciplex and the locally excited fluorophore quencher pair, a fully reversible interconversion between the RIP, exciplex, and locally excited fluorophore is revealed by spectrally resolved MFE measurements for the long-chain systems (n = 10, 16).
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Affiliation(s)
- Hao Minh Hoang
- Ho
Chi Minh City University of Technology and Education, Vo Van Ngan 01, Linh Chieu Ward, Thu Duc District, Ho Chi Minh City 700000, Vietnam
- Institute
of Physical and Theoretical Chemistry, Graz
University of Technology, Stremayrgasse 9/I, A-8010 Graz, Austria
| | - Van Thi Bich Pham
- Institute
of Physical and Theoretical Chemistry, Graz
University of Technology, Stremayrgasse 9/I, A-8010 Graz, Austria
| | - Günter Grampp
- Institute
of Physical and Theoretical Chemistry, Graz
University of Technology, Stremayrgasse 9/I, A-8010 Graz, Austria
| | - Daniel R. Kattnig
- Living
Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon EX4 4QD, United Kingdom
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14
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Zollitsch TM, Jarocha LE, Bialas C, Henbest KB, Kodali G, Dutton PL, Moser CC, Timmel CR, Hore PJ, Mackenzie SR. Magnetically Sensitive Radical Photochemistry of Non-natural Flavoproteins. J Am Chem Soc 2018; 140:8705-8713. [PMID: 29940116 DOI: 10.1021/jacs.8b03104] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is a remarkable fact that ∼50 μT magnetic fields can alter the rates and yields of certain free-radical reactions and that such effects might be the basis of the light-dependent ability of migratory birds to sense the direction of the Earth's magnetic field. The most likely sensory molecule at the heart of this chemical compass is cryptochrome, a flavin-containing protein that undergoes intramolecular, blue-light-induced electron transfer to produce magnetically sensitive radical pairs. To learn more about the factors that control the magnetic sensitivity of cryptochromes, we have used a set of de novo designed protein maquettes that self-assemble as four-α-helical proteins incorporating a single tryptophan residue as an electron donor placed approximately 0.6, 1.1, or 1.7 nm away from a covalently attached riboflavin as chromophore and electron acceptor. Using a specifically developed form of cavity ring-down spectroscopy, we have characterized the photochemistry of these designed flavoprotein maquettes to determine the identities and kinetics of the transient radicals responsible for the magnetic field effects. Given the gross structural and dynamic differences from the natural proteins, it is remarkable that the maquettes show magnetic field effects that are so similar to those observed for cryptochromes.
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Affiliation(s)
- Tilo M Zollitsch
- Department of Chemistry , University of Oxford, Physical and Theoretical Chemistry Laboratory , Oxford OX1 3QZ , United Kingdom
| | - Lauren E Jarocha
- Department of Chemistry , University of Oxford, Physical and Theoretical Chemistry Laboratory , Oxford OX1 3QZ , United Kingdom
| | - Chris Bialas
- Johnson Research Foundation, Department of Biochemistry and Biophysics , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Kevin B Henbest
- Department of Chemistry , University of Oxford, Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory , Oxford OX1 3QR , United Kingdom
| | - Goutham Kodali
- Johnson Research Foundation, Department of Biochemistry and Biophysics , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - P Leslie Dutton
- Johnson Research Foundation, Department of Biochemistry and Biophysics , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Christopher C Moser
- Johnson Research Foundation, Department of Biochemistry and Biophysics , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Christiane R Timmel
- Department of Chemistry , University of Oxford, Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory , Oxford OX1 3QR , United Kingdom
| | - P J Hore
- Department of Chemistry , University of Oxford, Physical and Theoretical Chemistry Laboratory , Oxford OX1 3QZ , United Kingdom
| | - Stuart R Mackenzie
- Department of Chemistry , University of Oxford, Physical and Theoretical Chemistry Laboratory , Oxford OX1 3QZ , United Kingdom
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15
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Yao GH, Gui KT, Ling X. Transport effects and chemical effects on NO removal by SCR with NH3
over iron-based catalyst in a magnetically fluidized bed. CAN J CHEM ENG 2018. [DOI: 10.1002/cjce.23207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Gui-huan Yao
- School of Mechanical and Power Engineering; Nanjing Tech University; Puzhu Road South #30 Nanjing 211816 P. R. China
| | - Ke-ting Gui
- School of Energy and Environment; Southeast University; Sipai Lou #2 Nanjing 210096 P. R. China
| | - Xiang Ling
- School of Mechanical and Power Engineering; Nanjing Tech University; Puzhu Road South #30 Nanjing 211816 P. R. China
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Miura T, Murai H. Effect of molecular diffusion on the spin dynamics of a micellized radical pair in low magnetic fields studied by Monte Carlo simulation. J Phys Chem A 2015; 119:5534-44. [PMID: 25942039 DOI: 10.1021/acs.jpca.5b02183] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Magnetic field effect is a powerful tool to study dynamics and kinetics of radical pairs (RPs), which are one of the most important intermediates for organic photon-energy conversion reactions. However, quantitative discussion regarding the relationship between the modulation of interelectron interactions and spin dynamics at low magnetic fields (<10 mT) is still an open question. We have studied the spin dynamics of a long-lived RP in a micelle by newly developed Monte Carlo simulation, in which fluctuations of the exchange and magnetic dipolar interactions by in-cage diffusion are directly introduced to the time-domain spin dynamics calculation. State-dependent relaxation/dephasing times of a few to a few tens of nanoseconds are obtained by simulations without hyperfine interactions (HFIs) as a function of the mutual diffusion constant (∼10(-6) cm(2)/s). Simulations with the HFIs exhibit incoherent singlet-triplet (S-T) mixings resulting from interplay between the HFIs and the fluctuating spin-spin interactions. The experimentally observed incoherent S-T mixing of ∼20 ns at 3 mT for a singlet-born RP in a sodium dodecyl sulfate micelle is reproduced by the simulation with reasonable diffusion coefficients. The computational method developed here contributes to quantitative detection of molecular motion that governs the recombination efficiency of RPs.
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Affiliation(s)
- Tomoaki Miura
- †Department of Chemistry, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan
| | - Hisao Murai
- ‡Department of Chemistry, Shizuoka University, 836 Oya, Suruga-ku, Shizuoka 422-8529, Japan
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Poonia VS, Saha D, Ganguly S. State transitions and decoherence in the avian compass. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:052709. [PMID: 26066201 DOI: 10.1103/physreve.91.052709] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Indexed: 06/04/2023]
Abstract
The radical pair model has been successful in explaining behavioral characteristics of the geomagnetic compass believed to underlie the navigation capability of certain avian species. In this study, the spin dynamics of the radical pair model and decoherence therein are interpreted from a microscopic state transition point of view. This helps to elucidate the interplay between the hyperfine and Zeeman interactions that enables the avian compass and clarify the distinctive effects of nuclear and environmental decoherence on it. Three regimes have been identified for the strength of the hyperfine interaction with respect to that of the geomagnetic Zeeman. It is found that the compass is likely to function in the large hyperfine interaction regime. Using a quantum information theoretic quantifier of coherence, we find that nuclear decoherence induces new structure in the spin dynamics for intermediate hyperfine interaction strength. On the other hand, environmental decoherence-modeled by two different noise models-seems to disrupt the compass action.
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Affiliation(s)
- Vishvendra Singh Poonia
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Dipankar Saha
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Swaroop Ganguly
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
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18
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Chakraborty B, Mitra P, Basu S. Spectroscopic exploration of drug–protein interaction: a study highlighting the dependence of the magnetic field effect on inter-radical separation distance formed during photoinduced electron transfer. RSC Adv 2015. [DOI: 10.1039/c5ra13575c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The magnetic field effect can be used as a “spectroscopic ruler” to assess inter-radical separation distances in photoinduced electron transfer.
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Affiliation(s)
| | - Piyali Mitra
- Chemical Sciences Division
- Saha Institute of Nuclear Physics
- Kolkata
- India
| | - Samita Basu
- Chemical Sciences Division
- Saha Institute of Nuclear Physics
- Kolkata
- India
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19
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Kais S. Introduction to Quantum Information and Computation for Chemistry. ADVANCES IN CHEMICAL PHYSICS 2014. [DOI: 10.1002/9781118742631.ch01] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Biskup T. Time-resolved electron paramagnetic resonance of radical pair intermediates in cryptochromes. Mol Phys 2013. [DOI: 10.1080/00268976.2013.833350] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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21
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Miura T. Supramolecular control of the spin-dependent dynamics of long-lived charge-separated states at the micellar interface as studied by magnetic field effect. J Phys Chem B 2013; 117:6443-54. [PMID: 23651159 DOI: 10.1021/jp401725f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spin selectivity in long-lived charge separation at the micellar interface is studied using the magnetic field effect (MFE). An amphiphilic viologen is complexed with a nonionic surfactant to form a supramolecular acceptor cage, of which the size is controlled by the acceptor concentration, as confirmed by dynamic light scattering measurement. Photoinduced electron transfer (ET) from a guest polyaromatic molecule to the viologen moiety is observed spin-dependently with time-resolved fluorescence (trFL) and transient absorption (TA). A negative MFE on the radical yield is successfully observed, which indicates generation of singlet-born long-lived radical pair that is realized by supramolecular control of the donor-acceptor (D-A) distances. The dominance of the singlet-precursor MFE is sensitive to the acceptor concentration, which presumably affects the D-A distance as well as the cage size. However, theoretical analysis of the MFE gives large recombination rates of ca. 10(8) s(-1), which indicate the contribution of spin-allowed recombination of the pseudocontact radical pair generated by still active in-cage diffusion. Dependence of the viologen concentration and alkyl chain length on the recombination and escape dynamics is discussed in terms of precursor spin states and the microenvironments in the cage.
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Affiliation(s)
- Tomoaki Miura
- Department of Chemistry, Faculty of Science and Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
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22
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Magnetically sensitive light-induced reactions in cryptochrome are consistent with its proposed role as a magnetoreceptor. Proc Natl Acad Sci U S A 2012; 109:4774-9. [PMID: 22421133 DOI: 10.1073/pnas.1118959109] [Citation(s) in RCA: 227] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Among the biological phenomena that fall within the emerging field of "quantum biology" is the suggestion that magnetically sensitive chemical reactions are responsible for the magnetic compass of migratory birds. It has been proposed that transient radical pairs are formed by photo-induced electron transfer reactions in cryptochrome proteins and that their coherent spin dynamics are influenced by the geomagnetic field leading to changes in the quantum yield of the signaling state of the protein. Despite a variety of supporting evidence, it is still not clear whether cryptochromes have the properties required to respond to magnetic interactions orders of magnitude weaker than the thermal energy, k(B)T. Here we demonstrate that the kinetics and quantum yields of photo-induced flavin-tryptophan radical pairs in cryptochrome are indeed magnetically sensitive. The mechanistic origin of the magnetic field effect is clarified, its dependence on the strength of the magnetic field measured, and the rates of relevant spin-dependent, spin-independent, and spin-decoherence processes determined. We argue that cryptochrome is fit for purpose as a chemical magnetoreceptor.
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23
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Jones J, Maeda K, Hore P. Reaction operators for spin-selective chemical reactions of radical pairs. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.03.082] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Gauger EM, Rieper E, Morton JJL, Benjamin SC, Vedral V. Sustained quantum coherence and entanglement in the avian compass. PHYSICAL REVIEW LETTERS 2011; 106:040503. [PMID: 21405313 DOI: 10.1103/physrevlett.106.040503] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 11/23/2010] [Indexed: 05/30/2023]
Abstract
In artificial systems, quantum superposition and entanglement typically decay rapidly unless cryogenic temperatures are used. Could life have evolved to exploit such delicate phenomena? Certain migratory birds have the ability to sense very subtle variations in Earth's magnetic field. Here we apply quantum information theory and the widely accepted "radical pair" model to analyze recent experimental observations of the avian compass. We find that superposition and entanglement are sustained in this living system for at least tens of microseconds, exceeding the durations achieved in the best comparable man-made molecular systems. This conclusion is starkly at variance with the view that life is too "warm and wet" for such quantum phenomena to endure.
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Affiliation(s)
- Erik M Gauger
- Department of Materials, University of Oxford, Oxford, United Kingdom
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25
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Miura T, Kageyama A, Torii S, Murai H. Photoreactions and Molecular Dynamics of Radical Pairs in a Reversed Micelle Studied by Time-Resolved Measurements of EPR and Magnetic Field Effect. J Phys Chem B 2010; 114:14550-8. [DOI: 10.1021/jp102300z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomoaki Miura
- Graduate School of Science and Engineering and Department of Chemistry, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan, and Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Atsushi Kageyama
- Graduate School of Science and Engineering and Department of Chemistry, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan, and Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Sakiko Torii
- Graduate School of Science and Engineering and Department of Chemistry, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan, and Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Hisao Murai
- Graduate School of Science and Engineering and Department of Chemistry, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan, and Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
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26
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Scott AM, Miura T, Ricks AB, Dance ZEX, Giacobbe EM, Colvin MT, Wasielewski MR. Spin-Selective Charge Transport Pathways through p-Oligophenylene-Linked Donor−Bridge−Acceptor Molecules. J Am Chem Soc 2009; 131:17655-66. [DOI: 10.1021/ja907625k] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Amy M. Scott
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113
| | - Tomoaki Miura
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113
| | - Annie Butler Ricks
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113
| | - Zachary E. X. Dance
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113
| | - Emilie M. Giacobbe
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113
| | - Michael T. Colvin
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113
| | - Michael R. Wasielewski
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113
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27
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Das D, Nath DN. Photoreaction of Thioxanthone with Indolic and Phenolic Derivatives of Biological Relevance: Magnetic Field Effect Study. J Phys Chem A 2008; 112:11619-26. [DOI: 10.1021/jp806880s] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Doyel Das
- Department of Physical Chemistry Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Deb Narayan Nath
- Department of Physical Chemistry Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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28
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Miura T, Murai H. Real-time observation of the spin-state mixing process of a micellized radical pair in weak magnetic fields by nanosecond fast field switching. J Phys Chem A 2008; 112:2526-32. [PMID: 18307324 DOI: 10.1021/jp077505x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The singlet-triplet spin-state mixing process of a singlet-born radical pair confined in a sodium dodecyl sulfate (SDS) micelle was studied by observing the nanosecond switched external magnetic field (SEMF) effect on the transient absorption signals. A long-lived singlet radical pair is generated by the photoinduced bond cleavage reaction of tetraphenylhydrazine in an SDS micelle. Application of off-on type SEMF results in the increase of the free radical yield contrary to the decrease produced by an applied static magnetic field. The S-T mixing process in low magnetic field was observed by means of a delay-shift SEMF experiment. Observed incoherent mixing processes are explained in terms of the interplay between coherent hyperfine interaction and fast dephasing processes caused by the fluctuation of electron-spin interactions. Singlet-triplet and triplet-triplet dephasing rate constants are determined independently to be 2 x 10(8) and 0.2 x 10(8) s(-)1, respectively, by a simulation based on a modified single-site Liouville equation. This is the first direct observation of the incoherent spin-state mixing process at magnetic fields comparable to the hyperfine interactions of the radical pair.
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Affiliation(s)
- Tomoaki Miura
- Graduate School of Science and Engineering, Faculty of Science, Shizuoka University, 836 Oya, Surugaku, Shizuoka 422-8529, Japan
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29
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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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30
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Woodward JR, Foster TJ, Salaoru AT, Vink CB. Direct observation of f-pair magnetic field effects and time-dependence of radical pair composition using rapidly switched magnetic fields and time-resolved infrared methods. Phys Chem Chem Phys 2008; 10:4020-6. [DOI: 10.1039/b719454d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Salaoru TA, Woodward JR. Rapid rise time pulsed magnetic field circuit for pump-probe field effect studies. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:036104. [PMID: 17411229 DOI: 10.1063/1.2713434] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Here we describe an electronic circuit capable of producing rapidly switched dc magnetic fields of up to 20 mT with a rise time of 10 ns and a pulse length variable from 50 ns to more than 10 micros, suitable for use in the study of magnetic field effects on radical pair (RP) reactions. This corresponds to switching the field on a time scale short relative to the lifetime of typical RPs and maintaining it well beyond their lifetimes. Previous experiments have involved discharging a capacitor through a low inductance coil for a limited time using a switching circuit. These suffer from decaying field strength over the duration of the pulse given primarily by the ratio of the pulse width to the RC constant of the circuit. We describe here a simple yet elegant solution that completely eliminates this difficulty by employing a feedback loop. This allows a constant field to be maintained over the entire length of the pulse.
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Affiliation(s)
- T A Salaoru
- Department of Chemistry, University of Leicester, Leicester, United Kingdom
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