1
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Roger C, Schmiedel A, Holzapfel M, Lukzen NN, Steiner UE, Lambert C. The influence of hindered rotation on electron transfer and exchange interaction in triarylamine-triptycene-perylene diimide triads. Phys Chem Chem Phys 2024; 26:4954-4967. [PMID: 38277181 DOI: 10.1039/d3cp05785b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Stretched electron-donor-bridge-acceptor triads that exhibit intramolecular twisting degrees of freedom are capable of modulating exchange interaction (J) as well as electronic couplings through variable π-overlap at the linear bond links, affecting the rate constants of photoinduced charge separation and recombination. Here we present an in-depth investigation of such effects induced by methyl substituents leading to controlled steric hindrance of intramolecular twisting around biaryl axes. Starting from the parent structure, consisting of a triphenyl amine donor, a triptycene (TTC) bridge and a phenylene-perylene diimide acceptor (Me0), one of the two phenylene linkers attached to the TTC was ortho-substituted by two methyl groups (Me2, Me3), or both such phenylene linkers by two pairs of methyl groups (Me23). Photoinduced charge separation (kCS) leading to a charge-separated (CS) state was studied by fs-laser spectroscopy, charge recombination to either singlet ground state (kS) or to the first excited local triplet state of the acceptor (kT) by ns-laser spectroscopy, whereby kinetic magnetic field effects in an external magnetic field were recorded and analysed using quantum dynamic simulations of the spin dependent kinetics of the CS state. Kinetic spectra of the initial first order rate constants of charge recombination (k(B)) exhibited characteristic J-resonances progressing to lower fields in the series Me0, Me2, Me3, Me23. From the quantum simulations, the values of the parameters J, kS, kT and kSTD, the singlet/triplet dephasing constant, were obtained. They were analysed in terms of molecular dynamics simulations of the intramolecular twisting dynamics based on potentials calculated by density functional theory. Apart from kT, all of the parameters exhibit a clear correlation with the averaged cosine square products of the biaryl angles.
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Affiliation(s)
- Chantal Roger
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Alexander Schmiedel
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Marco Holzapfel
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Nikita N Lukzen
- International Tomography Center, Russia and Novosibirsk State University, Institutskaya 3a, Novosibirsk, Novosibirsk 630090, Russia
| | - Ulrich E Steiner
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany.
| | - Christoph Lambert
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
- Center for Nanosystems Chemistry, Universität Würzburg, Theodor-Boveri-Weg, D-97074 Würzburg, Germany
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2
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Matsuoka R, Kimura S, Miura T, Ikoma T, Kusamoto T. Single-Molecule Magnetoluminescence from a Spatially Confined Persistent Diradical Emitter. J Am Chem Soc 2023. [PMID: 37311307 DOI: 10.1021/jacs.3c01076] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Luminescent radicals are an emerging class of materials that exhibit unique photofunctions not found in closed-shell molecules due to their open-shell electronic structure. Particularly promising are photofunctions in which radical's spin and luminescence are correlated; for example, when a magnetic field can affect luminescence (i.e., magnetoluminescence, ML). These photofunctions could be useful in the new science of spin photonics. However, previous observations of ML in radicals have been limited to systems in which radicals are randomly doped in host crystals or polymerized through metal complexation. This study shows that a covalently linked luminescent radical dimer (diradical) can exhibit ML as a single-molecular property. This facilitates detailed elucidation of the requirements for and mechanisms of ML in radicals and can aid the rational design of ML-active radicals based on synthetic chemistry.
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Affiliation(s)
- Ryota Matsuoka
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Shojiro Kimura
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Tomoaki Miura
- Department of Chemistry, Faculty of Science, Niigata University, Niigata, 950-2181, Japan
| | - Tadaaki Ikoma
- Department of Chemistry, Faculty of Science, Niigata University, Niigata, 950-2181, Japan
| | - Tetsuro Kusamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
- JST-PRESTO, 4-1-8, Honcho, Kawaguchi, Saitama, 332-0012, Japan
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3
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Pažėra G, Benjamin P, Mouritsen H, Hore PJ. Isotope Substitution Effects on the Magnetic Compass Properties of Cryptochrome-Based Radical Pairs: A Computational Study. J Phys Chem B 2023; 127:838-845. [PMID: 36669149 PMCID: PMC9900586 DOI: 10.1021/acs.jpcb.2c05335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The biophysical mechanism of the magnetic compass sense of migratory songbirds is thought to rely on the photochemical reactions of flavin-containing radical pairs in cryptochrome proteins located in the birds' eyes. A consequence of this hypothesis is that the effect of the Earth's magnetic field on the quantum yields of reaction products should be sensitive to isotopic substitutions that modify the hyperfine interactions in the radicals. In this report, we use spin dynamics simulations to explore the effects of 1H → 2H, 12C → 13C, and 14N → 15N isotopic substitutions on the functioning of cryptochrome 4a as a magnetic direction sensor. Two main conclusions emerge. (1) Uniform deuteration of the flavin chromophore appears to be the best way to boost the anisotropy of the magnetic field effect and to change its symmetry. (2) 13C substitution of three of the 12 flavin carbons, in particular C4, C4a, and C8α, seems to be the best recipe for attenuating the anisotropy. These predictions should give insight into the factors that control the magnetic sensitivity once spectroscopic techniques are available for measuring magnetic field effects on oriented protein samples.
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Affiliation(s)
| | - Philip Benjamin
- Department
of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
| | - Henrik Mouritsen
- Institut
für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg 26111, Germany,Research
Centre for Neurosensory Science, University
of Oldenburg, Oldenburg 26111, Germany
| | - P. J. Hore
- Department
of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.,
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4
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Bagryansky VA, Melnikov AR, Molin YN, Borovkov VI. The role of Heisenberg spin exchange and the quantum Zeno effect in the spin-selective reaction between spin-1/2 and spin-1 particles. J Chem Phys 2022; 157:064306. [PMID: 35963733 DOI: 10.1063/5.0101173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The kinetics of spin-selective reactions involving triplet molecules, such as triplet-triplet annihilation or electron transfer to dioxygen molecules in the ground triplet spin state, are strongly dependent on the dipole-dipole interaction (DDI) of electron spins in spin-1 particles. The effect of this interaction on the intersystem crossing in the reaction encounter complex of the paramagnetic particles was previously considered for some particular cases using oversimplified approaches. In this study, we consider a rigorous kinetic model of the irreversible reaction between the spin-1/2 and spin-1 particles in an encounter complex with the reactive doublet state. This model explicitly includes both isotropic exchange coupling of the reactants and spin dependence of the reaction rate in the form of the Haberkorn reaction term. For the time-independent DDI, an analytical expression for the reaction kinetics was derived. The effect of DDI fluctuations was analyzed using numerical simulations. It was found that increasing both the exchange coupling and the reaction rate constants can significantly slow down the quartet-doublet spin transitions and, as a consequence, the observed spin-selective reaction rate. Additionally, the presence of the irreversible reaction in the doublet states affects a coherent evolution in the non-reactive quartet subsystem.
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Affiliation(s)
- Victor A Bagryansky
- Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3, Institutskaya str., 630090 Novosibirsk, Russia
| | - Anatoly R Melnikov
- Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3, Institutskaya str., 630090 Novosibirsk, Russia
| | - Yuri N Molin
- Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3, Institutskaya str., 630090 Novosibirsk, Russia
| | - Vsevolod I Borovkov
- Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, 3, Institutskaya str., 630090 Novosibirsk, Russia
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5
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Buck JT, Mani T. Magnetic Control of Recombination Fluorescence and Tunability by Modulation of Radical Pair Energies in Rigid Donor–Bridge–Acceptor Systems. J Am Chem Soc 2020; 142:20691-20700. [DOI: 10.1021/jacs.0c09146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jason T. Buck
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Tomoyasu Mani
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
- PRESTO, JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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6
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Lukzen NN, Ivanov KL, Sadovsky VM, Sagdeev RZ. Magnetic field effect on recombination of radicals diffusing on a two-dimensional plane. J Chem Phys 2020; 152:034103. [PMID: 31968965 DOI: 10.1063/1.5131583] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Magnetic Field Effects (MFEs) on the recombination of radicals, which diffuse on an infinite plane, are studied theoretically. The case of spin-selective diffusion-controlled recombination of Radical Pairs (RPs) starting from a random spin state is considered assuming uniform initial distribution of the radicals. In this situation, reaction kinetics is described by a time-dependent rate coefficient K(t), which tends to zero at long times. Strong MFEs on K(t) are predicted that originate from the Δg and hyperfine driven singlet-triplet mixing in the RP. The effects of spin relaxation on the magnetic field are studied, as well as the influence of the dipole-dipole interaction between the electron spins of the RP. In the two-dimensional case, this interaction is not averaged out by diffusion and it strongly affects the MFE. The results of this work are of importance for interpreting MFEs on lipid peroxidation, a magnetosensitive process occurring on two-dimensional surfaces of cell membranes.
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Affiliation(s)
- Nikita N Lukzen
- International Tomography Center, Siberian Branch, Russian Academy of Sciences, Institutskaya Str. 3a, Novosibirsk 630090, Russia
| | - Konstantin L Ivanov
- International Tomography Center, Siberian Branch, Russian Academy of Sciences, Institutskaya Str. 3a, Novosibirsk 630090, Russia
| | - Vladimir M Sadovsky
- Institute of Computational Modeling, Siberian Branch, Russian Academy of Sciences, Akademgorodok 50/44, Krasnoyarsk 660036, Russia
| | - Renad Z Sagdeev
- International Tomography Center, Siberian Branch, Russian Academy of Sciences, Institutskaya Str. 3a, Novosibirsk 630090, Russia
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7
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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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8
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Miura T, Miyaji K, Horikoshi T, Suzuki S, Kozaki M, Okada K, Ikoma T. Spin-dependent electron transfer dynamics in a platinum-complex-donor-acceptor triad studied by transient-absorption detected magnetic field effect. J Chem Phys 2019; 151:234306. [PMID: 31864281 DOI: 10.1063/1.5127940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
For realization of efficient organic light-energy conversion systems, controlling the lifetime of photogenerated charge separated states in donor (D)-acceptor (A) molecules is of much importance; the spin dynamics is one of the important controlling factors. We previously reported that the covalently-linked 1,3-bis(2-pyridylimino)-isoindolate platinum (BPIPt)-dimethoxytriphenylamine (D)-naphthaldiimide (A) triad molecule (BPIPt-DA) exhibits a triplet-born long-lived charge separated state (BPIPt-D•+A•-), the lifetime of which is significantly increased from 4 µs to 10 µs by an applied magnetic field of 270 mT in room temperature tetrahydrofuran (THF). The purpose of the present study is to clarify detailed dynamics of spin-dependent generation and the decay of BPIPt-D+A-. For this purpose, we measured transient optical absorption (TA) and the TA-detected magnetic field effect (MFE) as functions of temperature and dispersion media. In THF at 183 K, MFE-detected transient spectra of the intermediate BPIPt•--D•+A state are observed. We have successfully quantified the recombination loss at this state by a kinetic simulation of MFE without using any reference molecules. The lifetime of the final BPIPt-D•+A•- state in a cellulose acetate polymer matrix at room temperature is significantly prolonged to 20 µs at 0 mT and 96 µs at 250 mT compared to those in THF. From the comparison of temperature dependences of the two media, effects of molecular motions on the electronic coupling and the spin relaxation are discussed.
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Affiliation(s)
- Tomoaki Miura
- Department of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Kio Miyaji
- Department of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Takafumi Horikoshi
- Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shuichi Suzuki
- Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Masatoshi Kozaki
- Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Keiji Okada
- Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Tadaaki Ikoma
- Department of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
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9
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Stass DV. On algebraic properties of the sub-block of zero field hyperfine Hamiltonian with penultimate total spin projection for arbitrary hyperfine structure, and field dependence of radical pair recombination probability in the vicinity of zero field. J Chem Phys 2019; 151:184112. [DOI: 10.1063/1.5127217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Dmitri V. Stass
- Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk, Russia
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10
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Fay TP, Lindoy LP, Manolopoulos DE. Electron spin relaxation in radical pairs: Beyond the Redfield approximation. J Chem Phys 2019; 151:154117. [DOI: 10.1063/1.5125752] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thomas P. Fay
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Lachlan P. Lindoy
- 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
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