1
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Huang Y, Qiu Y, Young RM, Schatz GC, Krzyaniak MD, Wasielewski MR. Identifying Sources of Entanglement Loss in Photodriven Molecular Electron Spin Teleportation. J Am Chem Soc 2024; 146:20133-20140. [PMID: 38995837 DOI: 10.1021/jacs.4c04393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
We report on an electron donor-electron acceptor-stable radical (D-A-R•) molecule in which an electron spin state first prepared on R• is followed by photogeneration of an entangled singlet 1[D•+-A•-] spin pair to produce D•+-A•--R•. Since the A•- and R• spins within D•+-A•--R• are uncorrelated, spin teleportation from R• to D•+ occurs with a maximal 25% efficiency only for the singlet pair 1(A•--R•) by spin-allowed electron transfer from A•- to R•. However, since 1[D•+-A•-] is sufficiently long-lived, coherent spin mixing involving the unreactive 3(A•--R•) population affects entanglement and teleportation within D•+-A•--R•. Pulse electron paramagnetic resonance experiments show a direct correlation between electron spin flip-flops and entanglement loss, providing information for designing molecular materials to serve as nanoscale quantum device interconnects.
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2
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Ohtsuka M, Ghosh K, Yim JCH, Sotome H, Okamoto T, Suda K, Kobori Y, Yokogawa D, Miyasaka H, Crudden CM, Nambo M. Visible-light-induced direct C-H alkylation of polycyclic aromatic hydrocarbons with alkylsulfones. Chem Sci 2024; 15:10592-10599. [PMID: 38994431 PMCID: PMC11234832 DOI: 10.1039/d4sc02577f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 05/25/2024] [Indexed: 07/13/2024] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are fragments of graphene that have attracted considerable attention as a new class of carbon-based materials. The functionalization of edge positions in PAHs is important to enable the modulation of physical and chemical properties essential for various applications. However, straightforward methods that combine functional group tolerance and regioselectivity remain sought after. Here we report a photochemical approach for the direct alkylation of carbon-hydrogen bonds in PAHs that takes place in a regiospecific manner, an outcome that has never been achieved in related thermal reactions. A reaction mechanism involving a single electron transfer process from photo-excited PAHs to sulfones, and a rationale for the origin of regioselectivity are proposed on the basis of spectroscopic analyses and theoretical calculations.
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Affiliation(s)
- Motoo Ohtsuka
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University Chikusa Nagoya Aichi 464-8601 Japan
| | - Koushik Ghosh
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University Chikusa Nagoya Aichi 464-8601 Japan
| | - Jacky C-H Yim
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University Chikusa Nagoya Aichi 464-8601 Japan
| | - Hikaru Sotome
- Division of Frontier Materials Science and Centre for Advanced Interdisciplinary Research, Graduate School of Engineering Science, Osaka University 1-3 Machikaneyama Toyonaka Osaka 560-8531 Japan
| | - Tsubasa Okamoto
- Molecular Photoscience Research Center, Kobe University 1-1 Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
- Department of Chemistry, Graduate School of Science, Kobe University 1-1, Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
| | - Kayo Suda
- Graduate School of Arts and Sciences, The University of Tokyo Komaba, Meguro-ku Tokyo 153-8902 Japan
| | - Yasuhiro Kobori
- Molecular Photoscience Research Center, Kobe University 1-1 Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
- Department of Chemistry, Graduate School of Science, Kobe University 1-1, Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
| | - Daisuke Yokogawa
- Graduate School of Arts and Sciences, The University of Tokyo Komaba, Meguro-ku Tokyo 153-8902 Japan
| | - Hiroshi Miyasaka
- Division of Frontier Materials Science and Centre for Advanced Interdisciplinary Research, Graduate School of Engineering Science, Osaka University 1-3 Machikaneyama Toyonaka Osaka 560-8531 Japan
| | - Cathleen M Crudden
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University Chikusa Nagoya Aichi 464-8601 Japan
- Department of Chemistry, Queen's University Chernoff Hall Kingston Ontario K7L 3N6 Canada
- Carbon to Metal Coating Institute, Queen's University Kingston Ontario K7L 3N6 Canada
| | - Masakazu Nambo
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University Chikusa Nagoya Aichi 464-8601 Japan
- Department of Chemistry, Graduate School of Science, Nagoya University Furo, Chikusa Nagoya Aichi 464-8601 Japan
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3
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Nishimura K, Yabuki R, Hamachi T, Kimizuka N, Tateishi K, Uesaka T, Yanai N. Dynamic Electron Polarization Lasting More Than 10 μs by Hybridizing Porphyrin and TEMPO with Flexible Linkers. J Phys Chem B 2023; 127:1219-1228. [PMID: 36717096 DOI: 10.1021/acs.jpcb.2c07936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Dynamic electron polarization (DEP), induced by quenching of photoexcited species by stable radicals, can hyperpolarize electron spins in solution at room temperature. Recently, development of technologies based on electron spin polarization such as dynamic nuclear polarization (DNP) has been progressing, where it is important to design molecules that achieve long-lasting DEP in addition to high DEP. Hybridization by linking dyes and radicals is a promising approach for efficient DEP, but strong interactions between neighboring dyes and radicals often result in the rapid decay of DEP. In this study, we introduce a flexible linker into the hybrid system of porphyrin and TEMPO to achieve both efficient DEP and long-lasting DEP. The structural flexibility of the linker switches the interaction between the radical and the triplet, which promotes the DEP process by bringing the radical and the triplet into close proximity, while avoiding abrupt relaxation due to strong interactions. As a result, the new hybridized system exhibits a larger DEP than the unlinked system, while at the same time achieving a DEP lasting more than 10 μs.
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Affiliation(s)
- Koki Nishimura
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka819-0395, Japan
| | - Reiya Yabuki
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka819-0395, Japan
| | - Tomoyuki Hamachi
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka819-0395, Japan
| | - Nobuo Kimizuka
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka819-0395, Japan
| | - Kenichiro Tateishi
- Cluster for Pioneering Research, RIKEN, RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama351-0198, Japan
| | - Tomohiro Uesaka
- Cluster for Pioneering Research, RIKEN, RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama351-0198, Japan
| | - Nobuhiro Yanai
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka819-0395, Japan
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4
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Nagatomo T, Vats AK, Matsuo K, Oyama S, Okamoto N, Suzuki M, Koganezawa T, Fuki M, Masuo S, Ohta K, Yamada H, Kobori Y. Nonpolymer Organic Solar Cells: Microscopic Phonon Control to Suppress Nonradiative Voltage Loss via Charge-Separated State. ACS PHYSICAL CHEMISTRY AU 2022; 3:207-221. [PMID: 36968446 PMCID: PMC10037453 DOI: 10.1021/acsphyschemau.2c00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/31/2022]
Abstract
Recent remarkable developments on nonfullerene solar cells have reached a photoelectric conversion efficiency (PCE) of 18% by tuning the band energy levels in small molecular acceptors. In this regard, understanding the impact of small donor molecules on nonpolymer solar cells is essential. Here, we systematically investigated mechanisms of solar cell performance using diketopyrrolopyrrole (DPP)-tetrabenzoporphyrin (BP) conjugates of C4-DPP-H2BP and C4-DPP-ZnBP, where C4 represents the butyl group substituted at the DPP unit as small p-type molecules, while an acceptor of [6,6]-phenyl-C61-buthylic acid methyl ester is employed. We clarified the microscopic origins of the photocarrier caused by phonon-assisted one-dimensional (1D) electron-hole dissociations at the donor-acceptor interface. Using a time-resolved electron paramagnetic resonance, we have characterized controlled charge-recombination by manipulating disorders in π-π donor stacking. This ensures carrier transport through stacking molecular conformations to suppress nonradiative voltage loss capturing specific interfacial radical pairs separated by 1.8 nm in bulk-heterojunction solar cells. We show that, while disordered lattice motions by the π-π stackings via zinc ligation are essential to enhance the entropy for charge dissociations at the interface, too much ordered crystallinity causes the backscattering phonon to reduce the open-circuit voltage by geminate charge-recombination.
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Affiliation(s)
- Takaaki Nagatomo
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1, Rokkodai-cho, Nada, Kobe657-8501, Japan
| | - Ajendra K. Vats
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara630-0192, Japan
| | - Kyohei Matsuo
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara630-0192, Japan
| | - Shinya Oyama
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1, Rokkodai-cho, Nada, Kobe657-8501, Japan
| | - Naoya Okamoto
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara630-0192, Japan
| | - Mitsuharu Suzuki
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka565-0871, Japan
| | - Tomoyuki Koganezawa
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo, Hyogo679-5198, Japan
| | - Masaaki Fuki
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1, Rokkodai-cho, Nada, Kobe657-8501, Japan
- Molecular Photoscience Research Center, Kobe University, 1-1, Rokkodai-cho, Nada, Kobe657-8501, Japan
| | - Sadahiro Masuo
- Department of Applied Chemistry for Environment, Kwansei Gakuin University, 2-1, Gakuen, Sanda, Hyogo669-1337, Japan
| | - Kaoru Ohta
- Molecular Photoscience Research Center, Kobe University, 1-1, Rokkodai-cho, Nada, Kobe657-8501, Japan
| | - Hiroko Yamada
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara630-0192, Japan
| | - Yasuhiro Kobori
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1, Rokkodai-cho, Nada, Kobe657-8501, Japan
- Molecular Photoscience Research Center, Kobe University, 1-1, Rokkodai-cho, Nada, Kobe657-8501, Japan
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5
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Ohta K, Tominaga K, Ikoma T, Kobori Y, Yamada H. Microscopic Structures, Dynamics, and Spin Configuration of the Charge Carriers in Organic Photovoltaic Solar Cells Studied by Advanced Time-Resolved Spectroscopic Methods. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:7365-7382. [PMID: 35675205 DOI: 10.1021/acs.langmuir.2c00290] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Organic photovoltaics (OPVs) are promising solutions for renewable energy and sustainable technologies and have attracted much attention in recent years. Two types of organic semiconductors are used as donor materials to fabricate OPV cells. One type is a photoconductive polymer, and the other type is a small-molecule-based compound. The discovery of a bulk-heterojunction (BHJ) structure using a mixture of p- and n-type organic semiconductors has dramatically increased the power conversion efficiency (PCE) of OPV cells. In this feature article, we review our recent studies on organic BHJ thin films and OPVs by using advanced time-resolved spectroscopic techniques. Two topics regarding the microscopic behaviors of the charge carriers are discussed. The first topic is focused on how to quantify the local mobility of the charge carriers. Here, we discuss charge carrier dynamics in diketopyrrolopyrrole-linked tetrabenzoporphyrin (DPP-BP) BHJ thin films studied by time-resolved terahertz spectroscopy on a subpicosecond to several tens of picoseconds time scale and by transient photocurrent measurements on a microsecond time scale. The second topic concerns the spin configuration and interaction of the electron and hole of the polaron pairs in polymer-based BHJ thin films and OPV cells studied by the time-resolved electron paramagnetic resonance method, time-resolved simultaneous optical and electrical detection, and measurement of the magnetoconductance effect.
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Affiliation(s)
- Kaoru Ohta
- Molecular Photoscience Research Center, Kobe University, Rokkodai-cho 1-1, Nada, Kobe, 657-8501, Japan
| | - Keisuke Tominaga
- Molecular Photoscience Research Center, Kobe University, Rokkodai-cho 1-1, Nada, Kobe, 657-8501, Japan
| | - Tadaaki Ikoma
- Graduate School of Science and Technology, Niigata University, 2-8050, Ikarashi, Nishi-ku, Niigata950-2181, Japan
| | - Yasuhiro Kobori
- Molecular Photoscience Research Center, Kobe University, Rokkodai-cho 1-1, Nada, Kobe, 657-8501, Japan
| | - Hiroko Yamada
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara630-0192, Japan
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6
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Hamada M, Iwata T, Fuki M, Kandori H, Weber S, Kobori Y. Orientations and water dynamics of photoinduced secondary charge-separated states for magnetoreception by cryptochrome. Commun Chem 2021; 4:141. [PMID: 36697801 PMCID: PMC9814139 DOI: 10.1038/s42004-021-00573-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 09/02/2021] [Indexed: 01/28/2023] Open
Abstract
In the biological magnetic compass, blue-light photoreceptor protein of cryptochrome is thought to conduct the sensing of the Earth's magnetic field by photoinduced sequential long-range charge-separation (CS) through a cascade of tryptophan residues, WA(H), WB(H) and WC(H). Mechanism of generating the weak-field sensitive radical pair (RP) is poorly understood because geometries, electronic couplings and their modulations by molecular motion have not been investigated in the secondary CS states generated prior to the terminal RP states. In this study, water dynamics control of the electronic coupling is revealed to be a key concept for sensing the direction of weak magnetic field. Geometry and exchange coupling (singlet-triplet energy gap: 2J) of photoinduced secondary CS states composed of flavin adenine dinucleotide radical anion (FAD-•) and radical cation WB(H)+• in the cryptochrome DASH from Xenopus laevis were clarified by time-resolved electron paramagnetic resonance. We found a time-dependent energetic disorder in 2J and was interpreted by a trap CS state capturing one reorientated water molecule at 120 K. Enhanced electron-tunneling by water-libration was revealed for the terminal charge-separation event at elevated temperature. This highlights importance of optimizing the electronic coupling for regulation of the anisotropic RP yield on the possible magnetic compass senses.
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Affiliation(s)
- Misato Hamada
- grid.31432.370000 0001 1092 3077Department of Chemistry, Graduate School of Science, Kobe University, 1‒1 Rokkodai‒cho, Nada‒ku, Kobe, 657‒8501 Japan
| | - Tatsuya Iwata
- grid.265050.40000 0000 9290 9879Department of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274‒8510 Japan
| | - Masaaki Fuki
- grid.31432.370000 0001 1092 3077Department of Chemistry, Graduate School of Science, Kobe University, 1‒1 Rokkodai‒cho, Nada‒ku, Kobe, 657‒8501 Japan ,grid.31432.370000 0001 1092 3077Molecular Photoscience Research Center, Kobe University, 1‒1 Rokkodai‒cho, Nada‒ku, Kobe, 657‒8501 Japan
| | - Hideki Kandori
- grid.47716.330000 0001 0656 7591Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555 Japan ,grid.47716.330000 0001 0656 7591OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555 Japan
| | - Stefan Weber
- grid.5963.9Institute of Physical Chemistry, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Yasuhiro Kobori
- grid.31432.370000 0001 1092 3077Department of Chemistry, Graduate School of Science, Kobe University, 1‒1 Rokkodai‒cho, Nada‒ku, Kobe, 657‒8501 Japan ,grid.31432.370000 0001 1092 3077Molecular Photoscience Research Center, Kobe University, 1‒1 Rokkodai‒cho, Nada‒ku, Kobe, 657‒8501 Japan
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7
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Harvey SM, Wasielewski MR. Photogenerated Spin-Correlated Radical Pairs: From Photosynthetic Energy Transduction to Quantum Information Science. J Am Chem Soc 2021; 143:15508-15529. [PMID: 34533930 DOI: 10.1021/jacs.1c07706] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
More than a half century ago, the NMR spectra of diamagnetic products resulting from radical pair reactions were observed to have strongly enhanced absorptive and emissive resonances. At the same time, photogenerated radical pairs were discovered to exhibit unusual electron paramagnetic resonance spectra that also had such resonances. These non-Boltzmann, spin-polarized spectra were observed in both chemical systems as well as in photosynthetic reaction center proteins following photodriven charge separation. Subsequent studies of these phenomena led to a variety of chemical electron donor-acceptor model systems that provided a broad understanding of the spin dynamics responsible for these spectra. When the distance between the two radicals is restricted, these observations result from the formation of spin-correlated radical pairs (SCRPs) in which the spin-spin exchange and dipolar interactions between the two unpaired spins play an important role in the spin dynamics. Early on, it was recognized that SCRPs photogenerated by ultrafast electron transfer are entangled spin pairs created in a well-defined spin state. These SCRPs can serve as spin qubit pairs (SQPs), whose spin dynamics can be manipulated to study a wide variety of quantum phenomena intrinsic to the field of quantum information science. This Perspective highlights the role of SCRPs as SQPs, gives examples of possible quantum manipulations using SQPs, and provides some thoughts on future directions.
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Affiliation(s)
- Samantha M Harvey
- Department of Chemistry, Center for Molecular Quantum Transduction, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry, Center for Molecular Quantum Transduction, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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8
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Bancroft L, Zhang J, Harvey SM, Krzyaniak MD, Zhang P, Schaller RD, Beratan DN, Young RM, Wasielewski MR. Charge Transfer and Spin Dynamics in a Zinc Porphyrin Donor Covalently Linked to One or Two Naphthalenediimide Acceptors. J Phys Chem A 2021; 125:825-834. [PMID: 33449684 DOI: 10.1021/acs.jpca.0c10471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Quantum coherence effects on charge transfer and spin dynamics in a system having two degenerate electron acceptors are studied using a zinc 5,10,15-tri(n-pentyl)-20-phenylporphyrin (ZnP) electron donor covalently linked to either one or two naphthalene-1,8:4,5-bis(dicarboximide) (NDI) electron acceptors using an anthracene (An) spacer, ZnP-An-NDI (1) and ZnP-An-NDI2 (2), respectively. Following photoexcitation of 1 and 2 in toluene at 295 K, femtosecond transient absorption spectroscopy shows that the electron transfer (ET) rate constant for 2 is about three times larger than that of 1, which can be accounted for by the statistical nature of incoherent ET as well as the electron couplings for the charge separation reactions. In contrast, the rate constant for charge recombination (CR) of 1 is about 25% faster than that of 2. Using femtosecond transient infrared spectroscopy and theoretical analysis, we find that the electron on NDI2•- in 2 localizes onto one of the two NDIs prior to CR, thus precluding electronically coherent CR from NDI2•-. Conversely, CR in both 1 and 2 is spin coherent as indicated by the observation of a resonance in the 3*ZnP yield following CR as a function of applied magnetic field, giving spin-spin exchange interaction energies of 2J = 210 and 236 mT, respectively, where the line width of the resonance for 2 is greater than 1. These data show that while CR is a spin-coherent process, incoherent hopping of the electron between the two NDIs in 2, consistent with the lack of delocalization noted above, results in greater spin decoherence in 2 relative to 1.
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Affiliation(s)
- Laura Bancroft
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Jinyuan Zhang
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Samantha M Harvey
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Matthew D Krzyaniak
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Peng Zhang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Richard D Schaller
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States.,Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David N Beratan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.,Departments of Biochemistry and Physics, Duke University, Durham, North Carolina 27708, United States
| | - Ryan M Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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9
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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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10
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Kobori Y, Fuki M, Nakamura S, Hasobe T. Geometries and Terahertz Motions Driving Quintet Multiexcitons and Ultimate Triplet–Triplet Dissociations via the Intramolecular Singlet Fissions. J Phys Chem B 2020; 124:9411-9419. [DOI: 10.1021/acs.jpcb.0c07984] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yasuhiro Kobori
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Masaaki Fuki
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Shunta Nakamura
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan
| | - Taku Hasobe
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan
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11
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Matsuda S, Oyama S, Kobori Y. Electron spin polarization generated by transport of singlet and quintet multiexcitons to spin-correlated triplet pairs during singlet fissions. Chem Sci 2020; 11:2934-2942. [PMID: 34122794 PMCID: PMC8157521 DOI: 10.1039/c9sc04949e] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Singlet fission (SF) is expected to exceed the Shockley–Queisser theoretical limit of efficiency of organic solar cells. Transport of spin-entanglement in the triplet–triplet pair state via one singlet exciton is a promising phenomenon for several energy conversion applications including quantum information science. However, direct observation of electron spin polarization by transport of entangled spin-states has not been presented. In this study, time-resolved electron paramagnetic resonance has been utilized to observe the transportation of singlet and quintet characters generating correlated triplet–triplet (T + T) exciton-pair states by probing the electron spin polarization (ESP) generated in thin films of 6,13-bis(triisopropylsilylethynyl)pentacene. We have clearly demonstrated that the ESP detected at the resonance field positions of individual triplet excitons is dependent on the morphology and on the detection delay time after laser flash to cause SF. ESP was clearly explained by quantum superposition of singlet–triplet–quintet wavefunctions via picosecond triplet-exciton dissociation as the electron spin polarization transfer from strongly exchange-coupled singlet and quintet TT states to weakly-coupled spin-correlated triplet pair states. Although the coherent superposition of spin eigenstates was not directly detected, the present interpretation of the spin correlation of the separated T + T exciton pair may pave new avenues not only for elucidating the vibronic role in the de-coupling between two excitons but also for scalable quantum information processing using quick T + T dissociation via one-photon excitation. Singlet fission (SF) is expected to exceed the Shockley–Queisser theoretical limit of efficiency of organic solar cells.![]()
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Affiliation(s)
- Saki Matsuda
- Department of Chemistry, Graduate School of Science, Kobe University 1-1 Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
| | - Shinya Oyama
- Department of Chemistry, Graduate School of Science, Kobe University 1-1 Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
| | - Yasuhiro Kobori
- Department of Chemistry, Graduate School of Science, Kobe University 1-1 Rokkodai-cho, Nada-ku Kobe 657-8501 Japan .,Molecular Photoscience Research Center, Kobe University 1-1 Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
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12
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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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13
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La Porte NT, Christensen JA, Krzyaniak MD, Rugg BK, Wasielewski MR. Spin-Selective Photoinduced Electron Transfer within Naphthalenediimide Diradicals. J Phys Chem B 2019; 123:7731-7739. [DOI: 10.1021/acs.jpcb.9b06303] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Nathan T. La Porte
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Joseph A. Christensen
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Matthew D. Krzyaniak
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Brandon K. Rugg
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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14
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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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15
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Olshansky JH, Krzyaniak MD, Young RM, Wasielewski MR. Photogenerated Spin-Entangled Qubit (Radical) Pairs in DNA Hairpins: Observation of Spin Delocalization and Coherence. J Am Chem Soc 2019; 141:2152-2160. [DOI: 10.1021/jacs.8b13155] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jacob H. Olshansky
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Matthew D. Krzyaniak
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Ryan M. Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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16
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Tripathi AK, Kundu S, Das R. Distance-dependent formation of electronic charge-transfer states in the ground states of anthracene and pyrene covalently linked to a TEMPO free radical. Phys Chem Chem Phys 2018; 21:77-88. [PMID: 30515493 DOI: 10.1039/c8cp06722h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Charge-transfer (CT) electronic states are generally seen in molecules involving interactions between species of low ionization potential and high electron affinity. In this context, the 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) free radical is not considered to be a typical molecule to form charge transfer states with aromatic hydrocarbons. Nevertheless, involvement of such CT states has been invoked in rationalising the spin-dependent photophysical quenching of excited states of aromatic systems by TEMPO during bimolecular collisions. Direct observation of such CT states, however, has been elusive until recently, with our first report on the observation of CT states involving naphthalene and TEMPO moieties covalently linked through a spacer group (Rane et al., J. Fluoresc., 2015, 25, 1351-1361). With a view to demonstrating more systems of CT states involving a TEMPO donor, and establishing a possible dependence on its distance from an acceptor chromophore, we have now extended our investigation to anthracene (An) and pyrene (Py) moieties linked to TEMPO, using two different spacer groups of different lengths. The molecules are An-CH2-O-TEMPO, Py-CH2-O-TEMPO, Py-(CH2)2-O-TEMPO, Py-(CH2)4-O-TEMPO, Py-CH2-CO-O-TEMPO and Py-(CH2)3-CO-O-TEMPO, where a linear alkyl chain containing an ether or an ester moiety constitutes the spacer group. We established the formation of CT states in their ground states by comparing their electronic absorption spectra, steady-state fluorescence spectra and time-resolved fluorescence signals with those of the parent molecules An-CH2-OH, Py-CH2-OH and Py-CH2-COOH. CT bands of appreciable intensity were seen only with An-CH2-O-TEMPO, Py-CH2-O-TEMPO and Py-CH2-CO-O-TEMPO, the molecules with the shortest spacer group. Approximate shapes of the absorption and emission bands of the CT states have been determined. For the rest, very weak bands were seen. Similar trends were seen in their fluorescence lifetimes also. Absorption intensities of the CT bands were found to decrease exponentially with the length of the spacer group. The presence of the ether or the ester moiety in the spacer groups showed little influence on the intensities of the CT bands. Our results are probably the first experimental demonstration of the expected exponential dependence of the efficiency of the formation of CT states on the length of the spacer groups of chromophore-TEMPO linked molecules.
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Affiliation(s)
- Alok Kumar Tripathi
- Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
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17
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Schäfer J, Holzapfel M, Schmiedel A, Steiner UE, Lambert C. Fine tuning of electron transfer and spin chemistry parameters in triarylamine-bridge-naphthalene diimide dyads by bridge substituents. Phys Chem Chem Phys 2018; 20:27093-27104. [PMID: 30334029 DOI: 10.1039/c8cp04910f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photoinduced charge separation and charge recombination in a set of four molecular dyads consisting of a triarylamine donor and a naphthalene diimide acceptor were investigated by time resolved transient absorption spectroscopy with fs and ns time resolution. In these dyads the donor and acceptor are bridged by a meta-conjugated diethynylbenzene bridge whose electronic nature was tuned by small electron donating (OMe, Me) or electron withdrawing (Cl, CN) substituents. While the formation of the transient charge separated states is complete within tens of ps, charge recombination is biphasic with a shorter component of several hundred ns and a longer component of several microseconds. This behaviour could be rationalized by assuming an equilibrium of singlet and triplet charge separated states. Magnetic field dependent measurements showed a strong influence on the biphasic decay kinetics and also a pronounced level crossing effect in the magnetic field affected reaction yield (MARY) spectra caused by a significant exchange coupling. An analysis of the observed kinetics using classical kinetic rate equations yields rate constants for charge separation and charge recombination as well as the exchange interaction splitting in the radical ion pair, all of them showing a delicate dependence on the bridge substituents.
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Affiliation(s)
- Julian Schäfer
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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18
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Umeyama T, Imahori H. Electron transfer and exciplex chemistry of functionalized nanocarbons: effects of electronic coupling and donor dimerization. NANOSCALE HORIZONS 2018; 3:352-366. [PMID: 32254123 DOI: 10.1039/c8nh00024g] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the past few decades, research on the construction of donor-bridge-acceptor linked systems capable of efficient photoinduced charge separation has fundamentally contributed to the fields of artificial photosynthesis and solar energy conversion. Specifically, the above systems are often fabricated by using carbon-based nanomaterials such as fullerenes, carbon nanotubes, and graphenes, offering limitless possibilities of tuning their optical and electronic properties. Accordingly, since understanding the structure-photodynamics relationships of π-aromatic donor-bridge-nanocarbon linked systems is crucial for extracting the full potential of nanocarbon materials, this review summarizes recent research on their photophysical properties featuring nanocarbon materials as electron acceptors. In particular, we highlight the electronic coupling effects on the photodynamics of donor-bridge-nanocarbon acceptor linked systems, together with the effects of donor dimerization. On a basis of their time-resolved spectroscopic data, the photodynamics of donor-bridge-nanocarbon acceptor linked systems is shown to be substantially influenced by the formation and decay of an exciplex state, i.e., an excited-state consisting of a π-molecular donor and a nanocarbon acceptor with partial charge-transfer character. Such basic information is essential for realizing future application of carbon-based nanomaterials in optoelectronic and energy conversion devices.
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Affiliation(s)
- Tomokazu Umeyama
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
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19
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Kondo T, Matsuoka M, Azai C, Kobayashi M, Itoh S, Oh-oka H. Light-Induced Electron Spin-Polarized (ESP) EPR Signal of the P800+ Menaquinone– Radical Pair State in Oriented Membranes of Heliobacterium modesticaldum: Role/Location of Menaquinone in the Homodimeric Type I Reaction Center. J Phys Chem B 2018; 122:2536-2543. [DOI: 10.1021/acs.jpcb.7b12171] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Toru Kondo
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8602, Japan
| | - Masahiro Matsuoka
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
| | - Chihiro Azai
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
| | - Masami Kobayashi
- Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
| | - Shigeru Itoh
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8602, Japan
| | - Hirozo Oh-oka
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka 560-0043, Japan
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20
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Logsdon JL, Hartnett PE, Nelson JN, Harris MA, Marks TJ, Wasielewski MR. Charge Separation Mechanisms in Ordered Films of Self-Assembled Donor-Acceptor Dyad Ribbons. ACS APPLIED MATERIALS & INTERFACES 2017; 9:33493-33503. [PMID: 28430417 DOI: 10.1021/acsami.7b02585] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Orthogonal attachment of polar and nonpolar side-chains to a zinc porphyrin-perylenediimide dyad (ZnP-PDI, 1a) is shown to result in self-assembly of ordered supramolecular ribbons in which the ZnP and PDI molecules form segregated π-stacked columns. Following photoexcitation of the ordered ribbons, ZnP+•-PDI-• radical ion pairs form in <200 fs and subsequently produce a 30 ± 3% yield of free charge carriers that live for about 100 μs. Elongating the side chains on ZnP and PDI in 1b enhances the order of the films, but does not result in an increase in free charge carrier yield. In addition, this yield is independent of temperature, free energy of reaction, and the ZnP-PDI distance in the covalent dyad. These results suggest that the free charge carrier yield in this system is not limited by a bound charge transfer (CT) state or promoted by a vibronically hot CT state. Instead, it is likely that π-stacking of the segregated donors and acceptors within the ribbons results in delocalization of the charges following photoexcitation, allowing them to overcome Coulombic attraction and generate free charge carriers.
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Affiliation(s)
- Jenna L Logsdon
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Patrick E Hartnett
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Jordan N Nelson
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Michelle A Harris
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Tobin J Marks
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
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21
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Miura T, Fujiwara D, Akiyama K, Horikoshi T, Suzuki S, Kozaki M, Okada K, Ikoma T. Magnetic Control of the Charge-Separated State Lifetime Realized by Covalent Attachment of a Platinum Complex. J Phys Chem Lett 2017; 8:661-665. [PMID: 28085290 DOI: 10.1021/acs.jpclett.6b02887] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Dynamics of the photogenerated charge-separated (CS) state is studied for a newly synthesized molecular triad, in which the donor (D) dimethoxytriphenylamine, 1,3-bis(2-pyridylimino)isoindolate platinum (BPIPt), and the acceptor (A) naphthaldiimide are linked with a triethynylbenzene unit (BPIPt-DA). Photoexcitation of BPIPt gives rise to generation of a long-lived (∼4 μs) CS state BPIPt-D+A-, of which the lifetime is considerably increased by an applied magnetic field of 270 mT. The positive magnetic field effect (MFE) is in contrast to the negative MFE for the reference DA molecule, which indicates successful switching of the initial spin state of the CS state from singlet to triplet. Simulations of the MFE and time-resolved electron paramagnetic resonance show that spin-selective charge recombination and spin relaxation are unaffected by attachment of BPIPt. The minimum impact of heavy atom substitution on the electronic and magnetic properties has been realized by the small electronic coupling mediated by the rigid meta-triethynylbenzene.
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Affiliation(s)
- Tomoaki Miura
- Department of Chemistry, Faculty of Science, Niigata University , 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Dai Fujiwara
- Department of Chemistry, Faculty of Science, Niigata University , 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Kimio Akiyama
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Aoba-ku, Sendai 980-8577, 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 Chemistry, Faculty of Science, Niigata University , 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
- Center for Instrumental Analysis, Niigata University , 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
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22
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Wu YL, Horwitz NE, Chen KS, Gomez-Gualdron DA, Luu NS, Ma L, Wang TC, Hersam MC, Hupp JT, Farha OK, Snurr RQ, Wasielewski MR. G-quadruplex organic frameworks. Nat Chem 2016; 9:466-472. [DOI: 10.1038/nchem.2689] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/03/2016] [Indexed: 11/09/2022]
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23
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Evans EW, Kattnig DR, Henbest KB, Hore PJ, Mackenzie SR, Timmel CR. Sub-millitesla magnetic field effects on the recombination reaction of flavin and ascorbic acid radicals. J Chem Phys 2016; 145:085101. [DOI: 10.1063/1.4961266] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Emrys W. Evans
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, Oxford, United Kingdom
| | - Daniel R. Kattnig
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Kevin B. Henbest
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, Oxford, United Kingdom
| | - P. J. Hore
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Stuart R. Mackenzie
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Christiane R. Timmel
- Department of Chemistry, Centre for Advanced Electron Spin Resonance, University of Oxford, Oxford, United Kingdom
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24
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Fuki M, Murai H, Tachikawa T, Kobori Y. Time Resolved EPR Study on the Photoinduced Long-Range Charge-Separated State in Protein: Electron Tunneling Mediated by Arginine Residue in Human Serum Albumin. J Phys Chem B 2016; 120:4365-72. [DOI: 10.1021/acs.jpcb.6b01072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Masaaki Fuki
- Graduate
School of Science and Technology, Shizuoka University, 836 Ohya
Suruga-ku, Shizuoka 422-8529, Japan
| | - Hisao Murai
- Graduate
School of Science and Technology, Shizuoka University, 836 Ohya
Suruga-ku, Shizuoka 422-8529, Japan
| | - Takashi Tachikawa
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1
Rokkoudai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Yasuhiro Kobori
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1
Rokkoudai-cho, Nada-ku, Kobe 657-8501, Japan
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25
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Horwitz NE, Phelan BT, Nelson JN, Krzyaniak MD, Wasielewski MR. Picosecond Control of Photogenerated Radical Pair Lifetimes Using a Stable Third Radical. J Phys Chem A 2016; 120:2841-53. [PMID: 27108738 DOI: 10.1021/acs.jpca.6b02621] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photoinduced electron transfer reactions in organic donor-acceptor systems leading to long-lived radical ion pairs (RPs) have attracted broad interest for their potential applications in fields as diverse as solar energy conversion and spintronics. We present the photophysics and spin dynamics of an electron donor - electron acceptor - stable radical system consisting of a meta-phenylenediamine (mPD) donor covalently linked to a 4-aminonaphthalene-1,8-dicarboximide (ANI) electron-accepting chromophore as well as an α,γ-bisdiphenylene-β-phenylallyl (BDPA) stable radical. Selective photoexcitation of ANI produces the BDPA-mPD(+•)-ANI(-•) triradical in which the mPD(+•)-ANI(-•) RP spins are strongly exchange coupled. The presence of BDPA is found to greatly increase the RP intersystem crossing rate from the initially photogenerated BDPA-(1)(mPD(+•)-ANI(-•)) to BDPA-(3)(mPD(+•)-ANI(-•)), resulting in accelerated RP recombination via the triplet channel to produce BDPA-mPD-(3*)ANI as compared to a reference molecule lacking the BDPA radical. The RP recombination rates observed are much faster than those previously reported for weakly coupled triradical systems. Time-resolved EPR spectroscopy shows that this process is also associated with strong spin polarization of the stable radical. Overall, these results show that RP intersystem crossing rates can be strongly influenced by stable radicals nearby strongly coupled RP systems, making it possible to use a third spin to control RP lifetimes down to a picosecond time scale.
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Affiliation(s)
- Noah E Horwitz
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Brian T Phelan
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Jordan N Nelson
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Matthew D Krzyaniak
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and Institute for Sustainability and Energy at Northwestern, Northwestern University , Evanston, Illinois 60208-3113, United States
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26
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Miura T, Tao R, Shibata S, Umeyama T, Tachikawa T, Imahori H, Kobori Y. Geometries, Electronic Couplings, and Hole Dissociation Dynamics of Photoinduced Electron–Hole Pairs in Polyhexylthiophene–Fullerene Dyads Rigidly Linked by Oligophenylenes. J Am Chem Soc 2016; 138:5879-85. [DOI: 10.1021/jacs.5b13414] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Taku Miura
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1
Rokkodaicho, Nada-ku, Kobe 657-8501, Japan
| | - Ran Tao
- Department
of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Sho Shibata
- Department
of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Tomokazu Umeyama
- Department
of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Takashi Tachikawa
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1
Rokkodaicho, Nada-ku, Kobe 657-8501, Japan
| | - Hiroshi Imahori
- Department
of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
- Institute
for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yasuhiro Kobori
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1
Rokkodaicho, Nada-ku, Kobe 657-8501, Japan
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27
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Kobori Y, Miura T. Overcoming Coulombic Traps: Geometry and Electronic Characterizations of Light-Induced Separated Spins at the Bulk Heterojunction Interface. J Phys Chem Lett 2015; 6:113-123. [PMID: 26263099 DOI: 10.1021/jz5023202] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Recent progress is overviewed on experimental elucidations of fundamental molecular functions of the light-energy conversions by the photoactive layers of the organic photovoltalic (OPV) cells by means of the time-resolved electron paramagnetic resonance spectroscopy. Positions and orientations of the unpaired electrons and electronic coupling matrix elements are clarified in photoinduced, primary charge-separated (CS) states. Connections between the molecular geometries and the electronic couplings have been characterized for the initial CS states to elucidate how the structure, orbital delocalization, and molecular libration play roles on exothermic carrier dissociation via a vibrationally relaxed charge-transfer complex with prevention of the energy-wasting charge recombination. Superior functions to biological molecules are presented for the efficient photocurrent generations induced by orbital delocalization and by shallow trap depths at polymer-stacking domains. The above structural and electronic characteristics of the primary electron-hole pairs are essential to evaluations, designs, and developments of the efficient solar cells using organic molecules.
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Affiliation(s)
- Yasuhiro Kobori
- §Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkoudai-cho, Nada-ku, Kobe 657-8501, Japan
- †PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi-shi, Saitama 332-0012, Japan
| | - Taku Miura
- §Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkoudai-cho, Nada-ku, Kobe 657-8501, Japan
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28
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Miura T, Aikawa M, Kobori Y. Time-Resolved EPR Study of Electron-Hole Dissociations Influenced by Alkyl Side Chains at the Photovoltaic Polyalkylthiophene:PCBM Interface. J Phys Chem Lett 2014; 5:30-35. [PMID: 26276177 DOI: 10.1021/jz402300m] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nanosecond time-resolved electron paramagnetic resonance (TREPR) spectroscopy has been utilized at T = 77 K to characterize alkyl side-chain effects on geometries and on the electronic couplings (VCR) of transient charge-separated (CS) states in the photoactive layers fabricated by the spin-coating of mixed solutions of regioregular polyalkylthiophenes (RR-P3AT) and [6,6]-C61-butyric acid methyl ester (PCBM). By increasing the alkyl side-chain number from 6 to 12 in P3AT, a highly distant and long-lived CS state has been obtained. This result is explained by a coupling of the hole dissociation to the polymer librations by the side-chains. From an exponential decay of VCR with respect to the CS distance, the attenuation factor (βe) has been determined to be βe = 0.2 Å(-1). Such a long-range tunneling feature is explained by the generations of the shallowly trapped, delocalized electron-hole pairs by the dissociation of the hole toward π-stacking directions at the organic photovoltaic interface.
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Affiliation(s)
- Taku Miura
- †Department of Chemistry, Graduate School of Science, Shizuoka University, 836 Ohya Suruga-ku, Shizoka 422-8529, Japan
| | - Motoko Aikawa
- †Department of Chemistry, Graduate School of Science, Shizuoka University, 836 Ohya Suruga-ku, Shizoka 422-8529, Japan
| | - Yasuhiro Kobori
- ‡Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkoudai-cho, Nada-ku, Kobe 657-8501, Japan
- §PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi-shi, Saitama 332-0012, Japan
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29
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Colvin MT, Carmieli R, Miura T, Richert S, Gardner DM, Smeigh AL, Dyar SM, Conron SM, Ratner MA, Wasielewski MR. Electron Spin Polarization Transfer from Photogenerated Spin-Correlated Radical Pairs to a Stable Radical Observer Spin. J Phys Chem A 2013; 117:5314-25. [DOI: 10.1021/jp4045012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Michael T. Colvin
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Raanan Carmieli
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Tomoaki Miura
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Sabine Richert
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Daniel M. Gardner
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Amanda L. Smeigh
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Scott M. Dyar
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Sarah M. Conron
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Mark A. Ratner
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department
of Chemistry and Argonne-Northwestern Solar
Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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30
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Carmieli R, Smeigh AL, Mickley Conron SM, Thazhathveetil AK, Fuki M, Kobori Y, Lewis FD, Wasielewski MR. Structure and Dynamics of Photogenerated Triplet Radical Ion Pairs in DNA Hairpin Conjugates with Anthraquinone End Caps. J Am Chem Soc 2012; 134:11251-60. [DOI: 10.1021/ja303721j] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Raanan Carmieli
- Department of Chemistry and Argonne-Northwestern
Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Amanda L. Smeigh
- Department of Chemistry and Argonne-Northwestern
Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Sarah M. Mickley Conron
- Department of Chemistry and Argonne-Northwestern
Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Arun K. Thazhathveetil
- Department of Chemistry and Argonne-Northwestern
Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Masaaki Fuki
- Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya Surugaku, Shizuoka 422-8529,
Japan
| | - Yasuhiro Kobori
- Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya Surugaku, Shizuoka 422-8529,
Japan
- PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho
Kawaguchi, Saitama 332-0012, Japan
| | - Frederick D. Lewis
- Department of Chemistry and Argonne-Northwestern
Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Argonne-Northwestern
Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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31
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Kobori Y, Fuki M. Protein–Ligand Structure and Electronic Coupling of Photoinduced Charge-Separated State: 9,10-Anthraquinone-1-sulfonate Bound to Human Serum Albumin. J Am Chem Soc 2011; 133:16770-3. [DOI: 10.1021/ja206898j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Yasuhiro Kobori
- Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka 422-8529, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi-shi, Saitama 332-0012, Japan
| | - Masaaki Fuki
- Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka 422-8529, Japan
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32
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Scott AM, Wasielewski MR. Temperature Dependence of Spin-Selective Charge Transfer Pathways in Donor−Bridge−Acceptor Molecules with Oligomeric Fluorenone and p-Phenylethynylene Bridges. J Am Chem Soc 2011; 133:3005-13. [DOI: 10.1021/ja1095649] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Amy M. Scott
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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33
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Miura T, Wasielewski MR. Manipulating Photogenerated Radical Ion Pair Lifetimes in Wirelike Molecules Using Microwave Pulses: Molecular Spintronic Gates. J Am Chem Soc 2011; 133:2844-7. [DOI: 10.1021/ja110789q] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomoaki Miura
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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34
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Ricks AB, Solomon GC, Colvin MT, Scott AM, Chen K, Ratner MA, Wasielewski MR. Controlling Electron Transfer in Donor−Bridge−Acceptor Molecules Using Cross-Conjugated Bridges. J Am Chem Soc 2010; 132:15427-34. [DOI: 10.1021/ja107420a] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Annie Butler Ricks
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Gemma C. Solomon
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael T. Colvin
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Amy M. Scott
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Kun Chen
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Mark A. Ratner
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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35
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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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36
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Moribe S, Yonemura H, Wakita Y, Yamashita T, Yamada S. Reverse phenomena of magnetic field effects and time-resolved EPR spectra in the photogenerated biradical from intramolecular electron-transfer in a phenothiazine–C60linked compound with a semi-rigid spacer. Mol Phys 2010. [DOI: 10.1080/00268976.2010.497778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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37
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Kobori Y, Fuki M, Murai H. Electron Spin Polarization Transfer to the Charge-Separated State from Locally Excited Triplet Configuration: Theory and Its Application to Characterization of Geometry and Electronic Coupling in the Electron Donor−Acceptor System. J Phys Chem B 2010; 114:14621-30. [DOI: 10.1021/jp102330a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Yasuhiro Kobori
- Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya Surugaku, Shizuoka 422-8529 Japan
| | - Masaaki Fuki
- Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya Surugaku, Shizuoka 422-8529 Japan
| | - Hisao Murai
- Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya Surugaku, Shizuoka 422-8529 Japan
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38
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Scott A, Butler Ricks A, Colvin M, Wasielewski M. Comparing Spin-Selective Charge Transport through Donor-Bridge-Acceptor Molecules with Different Oligomeric Aromatic Bridges. Angew Chem Int Ed Engl 2010; 49:2904-8. [DOI: 10.1002/anie.201000171] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Indexed: 02/04/2023]
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39
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Scott A, Butler Ricks A, Colvin M, Wasielewski M. Comparing Spin-Selective Charge Transport through Donor-Bridge-Acceptor Molecules with Different Oligomeric Aromatic Bridges. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201000171] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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40
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Yago T, Gohdo M, Wakasa M. Hydrogen Bonding Effects on the Reorganization Energy for Photoinduced Charge Separation Reaction between Porphyrin and Quinone Studied by Nanosecond Laser Flash Photolysis. J Phys Chem B 2010; 114:2476-83. [DOI: 10.1021/jp909927w] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Tomoaki Yago
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Masao Gohdo
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Masanobu Wakasa
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
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41
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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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42
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Kobori Y, Shibano Y, Endo T, Tsuji H, Murai H, Tamao K. Time-resolved EPR characterization of a folded conformation of photoinduced charge-separated state in porphyrin-fullerene dyad bridged by diphenyldisilane. J Am Chem Soc 2009; 131:1624-5. [PMID: 19159228 DOI: 10.1021/ja8073775] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For development of the molecular solar-energy conversion systems, it is crucial to investigate how both the molecular geometry and electronic structure of electron donor-bridge-acceptor (D-B-A) molecules contribute to the electronic coupling for the charge-separation (CS) and charge-recombination (CR) processes. In a D-B-A system of a porphyrin-fullerene dyad (ZnP-C(60)) bridged by a diphenyldisilane spacer, we have characterized one specific folded molecular conformation in the CS state among several existing conformations using the time-resolved electron paramagnetic resonance (TREPR) method at low temperature. To determine the molecular conformation and spin-spin exchange coupling of the CS state, we have considered (1) the electron spin polarization transfer from the excited triplet state of the C(60) moiety to the CS state and (2) the sublevel-selective spin relaxations and CR in the CS state. In the CS state of this conformation, although the ZnP cation and C(60) anion radicals are in close proximity, direct overlap between their singly occupied molecular orbitals is small, resulting in detection of the long-lived CS state which has a totally different conformation from the optically detected, charge-transfer (CT) complex. It has been demonstrated that, among several folded and extended molecular conformations created by the flexibility of the -Si-Si- bridge, the EPR conformation can play a role on the prevention of the energy-wasting CR.
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Affiliation(s)
- Yasuhiro Kobori
- Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya Surugaku, Shizuoka 422-8529, Japan
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43
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Zeidan TA, Carmieli R, Kelley RF, Wilson TM, Lewis FD, Wasielewski MR. Charge-transfer and spin dynamics in DNA hairpin conjugates with perylenediimide as a base-pair surrogate. J Am Chem Soc 2008; 130:13945-55. [PMID: 18811163 DOI: 10.1021/ja803765r] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A perylenediimide chromophore (P) was incorporated into DNA hairpins as a base-pair surrogate to prevent the self-aggregation of P that is typical when it is used as the hairpin linker. The photoinduced charge-transfer and spin dynamics of these hairpins were studied using femtosecond transient absorption spectroscopy and time-resolved EPR spectroscopy (TREPR). P is a photooxidant that is sufficiently powerful to quantitatively inject holes into adjacent adenine (A) and guanine (G) nucleobases. The charge-transfer dynamics observed following hole injection from P into the A-tract of the DNA hairpins is consistent with formation of a polaron involving an estimated 3-4 A bases. Trapping of the (A 3-4) (+*) polaron by a G base at the opposite end of the A-tract from P is competitive with charge recombination of the polaron and P (-*) only at short P-G distances. In a hairpin having 3 A-T base pairs between P and G ( 4G), the radical ion pair that results from trapping of the hole by G is spin-correlated and displays TREPR spectra at 295 and 85 K that are consistent with its formation from (1*)P by the radical-pair intersystem crossing mechanism. Charge recombination is spin-selective and produces (3*)P, which at 85 K exhibits a spin-polarized TREPR spectrum that is diagnostic of its origin from the spin-correlated radical ion pair. Interestingly, in a hairpin having no G bases ( 0G), TREPR spectra at 85 K revealed a spin-correlated radical pair with a dipolar interaction identical to that of 4G, implying that the A-base in the fourth A-T base pair away from the P chromophore serves as a hole trap. Our data suggest that hole injection and transport in these hairpins is completely dominated by polaron generation and movement to a trap site rather than by superexchange. On the other hand, the barrier for charge injection from G (+*) back onto the A-T base pairs is strongly activated, so charge recombination from G (or even A trap sites at 85 K) most likely proceeds by a superexchange mechanism.
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Affiliation(s)
- Tarek A Zeidan
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, USA
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44
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Kawai A, Shibuya K. Charge-Transfer Controlled Exchange Interaction in Radical-Triplet Encounter Pairs as Studied by FT-EPR Spectroscopy. J Phys Chem A 2007; 111:4890-901. [PMID: 17518447 DOI: 10.1021/jp067753d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The exchange interaction, J, producing quartet and doublet energy separation in radical-triplet excited molecule encounter pairs, was investigated in solution by measuring chemically induced dynamic electron polarization (CIDEP) created through the radical-triplet pair mechanism. A time-resolved FT-EPR method was utilized to measure CIDEP of galvinoxyl radical by recording FID signals and an absolute magnitude of CIDEP, P(n), was determined for each radical-triplet system by detailed analysis of the time evolution curves of CIDEP. A transient FT-EPR signal phase remarkably depends on the triplet molecule. The signal phase is related to the sign of J value, which is responsible for the radical-triplet pair interaction. Most of galvinoxyl-triplet systems showed normal negative sign. An unusual positive sign was found in some systems characterized by a small energy gap, DeltaG, between the radical-triplet pair and intermolecular charge transfer (CT) states. A theoretical calculation of J value for radical-triplet encounter pairs was carried out by considering exchange integral and intermolecular CT interaction. According to the calculated J value and the diffusion theory for CIDEP magnitude, experimental Pn values were theoretically reproduced as a function of DeltaG. The present results confirm our previously reported CT model explaining the complicated nature of the sign of J value in the galvinoxyl-triplet encounter pairs. According to the proposed model for CT effect on J value and CIDEP results, nature of J value in radical-triplet pairs is discussed.
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Affiliation(s)
- Akio Kawai
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ohokayama, Tokyo 152-8551, Japan.
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45
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Ichino T, Fessenden RW. Reactions of Hydrated Electron with Various Radicals: Spin Factor in Diffusion-Controlled Reactions. J Phys Chem A 2007; 111:2527-41. [PMID: 17388346 DOI: 10.1021/jp0684527] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reactions of hydrated electron (eaq-) with various radicals have been studied in pulse radiolysis experiments. These radicals are hydroxyl radical (*OH), sulfite radical anion (*SO3-), carbonate radical anion (CO3*-), carbon dioxide radical anion (*CO2-), azidyl radical (*N3), dibromine radical anion (Br2*-), diiodine radical anion (I2*-), 2-hydroxy-2-propyl radical (*C(CH3)2OH), 2-hydroxy-2-methyl-1-propyl radical ((*CH2)(CH3)2COH), hydroxycyclohexadienyl radical (*C6H6OH), phenoxyl radical (C6H5O*), p-methylphenoxyl radical (p-(H3C)C6H4O*), p-benzosemiquinone radical anion (p-OC6H4O*-), and phenylthiyl radical (C6H5S*). The kinetics of eaq- was followed in the presence of the counter radicals in transient optical absorption measurements. The rate constants of the eaq- reactions with radicals have been determined over a temperature range of 5-75 degrees C from the kinetic analysis of systems of multiple second-order reactions. The observed high rate constants for all the eaq- + radical reactions have been analyzed with the Smoluchowski equation. This analysis suggests that many of the eaq- + radical reactions are diffusion-controlled with a spin factor of 1/4, while other reactions with *OH, *N3, Br2*-, I2*-, and C6H5S* have spin factors significantly larger than 1/4. Spin dynamics for the eaq-/radical pairs is discussed to explain the different spin factors. The reactions with *OH, *N3, Br2*-, and I2*- have also been found to have apparent activation energies less than that for diffusion control, and it is suggested that the spin factors for these reactions decrease with increasing temperature. Such a decrease in spin factor may reflect a changing competition between spin relaxation/conversion and diffusive escape from the radical pairs.
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Affiliation(s)
- Takatoshi Ichino
- Radiation Laboratory and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5674, USA
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46
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Chernick ET, Mi Q, Vega AM, Lockard JV, Ratner MA, Wasielewski MR. Controlling Electron Transfer Dynamics in Donor−Bridge−Acceptor Molecules by Increasing Unpaired Spin Density on the Bridge. J Phys Chem B 2007; 111:6728-37. [PMID: 17309293 DOI: 10.1021/jp068741v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A t-butylphenylnitroxide (BPNO*) stable radical is attached to an electron donor-bridge-acceptor (D-B-A) system having well-defined distances between the components: MeOAn-6ANI-Ph(BPNO*)-NI, where MeOAn=p-methoxyaniline, 6ANI=4-(N-piperidinyl)naphthalene-1,8-dicarboximide, Ph=phenyl, and NI=naphthalene-1,8:4,5-bis(dicarboximide). MeOAn-6ANI, BPNO*, and NI are attached to the 1, 3, and 5 positions of the Ph bridge, respectively. Time-resolved optical and EPR spectroscopy show that BPNO* influences the spin dynamics of the photogenerated triradical states 2,4(MeOAn+*-6ANI-Ph(BPNO*)-NI-*), resulting in slower charge recombination within the triradical, as compared to the corresponding biradical lacking BPNO*. The observed spin-spin exchange interaction between the photogenerated radicals MeOAn+* and NI-* is not altered by the presence of BPNO*. However, the increased spin density on the bridge greatly increases radical pair (RP) intersystem crossing from the photogenerated singlet RP to the triplet RP. Rapid formation of the triplet RP makes it possible to observe a biexponential decay of the total RP population with components of tau=740 ps (0.75) and 104 ns (0.25). Kinetic modeling shows that the faster decay rate is due to rapid establishment of an equilibrium between the triplet RP and the neutral triplet state resulting from charge recombination, whereas the slower rate monitors recombination of the singlet RP to ground state.
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Affiliation(s)
- Erin T Chernick
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208-3113, USA
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47
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Dance ZEX, Mi Q, McCamant DW, Ahrens MJ, Ratner MA, Wasielewski MR. Time-Resolved EPR Studies of Photogenerated Radical Ion Pairs Separated by p-Phenylene Oligomers and of Triplet States Resulting from Charge Recombination. J Phys Chem B 2006; 110:25163-73. [PMID: 17165960 DOI: 10.1021/jp063690n] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Photoexcitation of a series of donor-bridge-acceptor (D-B-A) systems, where D = phenothiazine (PTZ), B = p-phenylene (Phn), n = 1-5, and A= perylene-3,4:9,10-bis(dicarboximide) (PDI) results in rapid electron transfer to produce 1(PTZ+*-Phn-PDI-*). Time-resolved EPR (TREPR) studies of the photogenerated radical pairs (RPs) show that above 150 K, when n = 2-5, the radical pair-intersystem crossing mechanism (RP-ISC) produces spin-correlated radical ion pairs having electron spin polarization patterns indicating that the spin-spin exchange interaction in the radical ion pair is positive, 2J > 0, and is temperature dependent. This temperature dependence is most likely due to structural changes of the p-phenylene bridge. Charge recombination in the RPs generates PTZ-Phn-3*PDI, which exhibits a spin-polarized signal similar to that observed in photosynthetic reaction-center proteins and some biomimetic systems. At temperatures below 150 K and/or at shorter donor-acceptor distances, e.g., when n = 1, PTZ-Phn-3*PDI is also formed from a competitive spin-orbit-intersystem crossing (SO-ISC) mechanism that is a result of direct charge recombination: 1(PTZ+*-Phn-PDI-*) --> PTZ-Phn-3*PDI. This SO-ISC mechanism requires the initial RP intermediate and depends strongly on the orientation of the molecular orbitals involved in the charge recombination as well as the magnitude of 2J.
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Affiliation(s)
- Zachary E X Dance
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208-3113, USA
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Wasielewski MR. Energy, Charge, and Spin Transport in Molecules and Self-Assembled Nanostructures Inspired by Photosynthesis. J Org Chem 2006; 71:5051-66. [PMID: 16808492 DOI: 10.1021/jo060225d] [Citation(s) in RCA: 479] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Electron transfer in biological molecules provides both insight and inspiration for developing chemical systems having similar functionality. Photosynthesis is an example of an integrated system in which light harvesting, photoinduced charge separation, and catalysis combine to carry out two thermodynamically demanding processes, the oxidation of water and the reduction of carbon dioxide. The development of artificial photosynthetic systems for solar energy conversion requires a fundamental understanding of electron-transfer reactions between organic molecules. Since these reactions most often involve single-electron transfers, the spin dynamics of photogenerated radical ion pairs provide important information on how the rates and efficiencies of these reactions depend on molecular structure. Given this knowledge, the design and synthesis of large integrated structures to carry out artificial photosynthesis is moving forward. An important approach to achieving this goal is the development of small, functional building blocks, having a minimum number of covalent bonds, which also have the appropriate molecular recognition sites to facilitate self-assembly into a complete, functional artificial photosynthetic system.
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Affiliation(s)
- Michael R Wasielewski
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208-3113, USA.
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Chernick ET, Mi Q, Kelley RF, Weiss EA, Jones BA, Marks TJ, Ratner MA, Wasielewski MR. Electron Donor−Bridge−Acceptor Molecules with Bridging Nitronyl Nitroxide Radicals: Influence of a Third Spin on Charge- and Spin-Transfer Dynamics. J Am Chem Soc 2006; 128:4356-64. [PMID: 16569012 DOI: 10.1021/ja0576435] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Appending a stable radical to the bridge molecule in a donor-bridge-acceptor system (D-B-A) is potentially an important way to control charge- and spin-transfer dynamics through D-B-A. We have attached a nitronyl nitroxide (NN*) stable radical to a D-B-A system having well-defined distances between the components: MeOAn-6ANI-Ph(NN*)-NI, where MeOAn = p-methoxyaniline, 6ANI = 4-(N-piperidinyl)naphthalene-1,8-dicarboximide, Ph = phenyl, and NI = naphthalene-1,8:4,5-bis(dicarboximide). MeOAn-6ANI, NN*, and NI are attached to the 1, 3, and 5 positions of the Ph bridge. Using both time-resolved optical and EPR spectroscopy, we show that NN* influences the spin dynamics of the photogenerated triradical states (2,4)(MeOAn(+)*-6ANI-Ph(NN*)-NI(-)*), resulting in slower charge recombination within the triradical compared to the corresponding biradical lacking NN*. The observed spin-spin exchange interaction between the photogenerated radicals MeOAn(+)(*) and NI(-)(*) is not altered by the presence of NN*, which only accelerates radical pair intersystem crossing. Charge recombination within the triradical results in the formation of (2,4)(MeOAn-6ANI-Ph(NN*)-(3)NI), in which NN* is strongly spin-polarized. Normally, the spin dynamics of correlated radical pairs do not produce a net spin polarization; however, net spin polarization appears on NN* with the same time constant as describes the photogenerated radical ion pair decay. This effect is attributed to antiferromagnetic coupling between NN* and the local triplet state (3)NI, which is populated following charge recombination. This requires an effective switch in the spin basis set between the triradical and the three-spin charge recombination product having both NN* and (3)NI present.
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Affiliation(s)
- Erin T Chernick
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
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Rozenshtein V, Berg A, Stavitski E, Levanon H, Franco L, Corvaja C. Electron Spin Polarization of Functionalized Fullerenes. Reversed Quartet Mechanism. J Phys Chem A 2005; 109:11144-54. [PMID: 16331897 DOI: 10.1021/jp0540104] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Time-resolved electron paramagnetic resonance (TREPR) spectroscopy was used to study two functionalized fullerenes consisting of a C60 moiety covalently linked to TEMPO radical via spacers of different length. Photoinduced electron spin polarization (ESP) reflecting a non-Boltzmann population within the energy levels of the spin system was observed in the electronic ground and excited states. Both fullerenes are characterized by a sign inversion of their TREPR spectra. A new mechanism of ESP generation was suggested to explain the experimental results. This mechanism, termed as the reversed quartet mechanism (RQM), includes the intersystem crossing process, which generates ESP in the excited trip-doublet and trip-quartet (2T1 and 4T1) states. This ISC is accompanied by ESP transfer to the ground state (2S0) by either electron-transfer reaction (in our case via charge transfer state, 2CT, i.e., 2T1--> 2CT --> 2S0 or internal conversion, 2T1--> 2S0.
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Affiliation(s)
- Vladimir Rozenshtein
- Department of Physical Chemistry and The Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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