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Mentzel P, Holzapfel M, Schmiedel A, Günther J, Michel M, Krummenacher I, Wodyński A, Kaupp M, Braunschweig H, Lambert C. Structure and Photophysics of N-Tolanyl-phenochalcogenazines and their Radical Cations. Chemistry 2024; 30:e202303782. [PMID: 38293898 DOI: 10.1002/chem.202303782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/16/2024] [Accepted: 01/26/2024] [Indexed: 02/01/2024]
Abstract
The study focuses on the structural and photophysical characteristics of neutral and oxidized forms of N-tolanyl-phenochalcogenazines PZX-tolan with X=O, S, Se, and Te. X-ray crystal structure analyses show a pseudo-equatorial (pe) structure of the tolan substituent in the O, S, and Se dyads, while the Te dyad possesses a pseudo-axial (pa) structure. DFT calculations suggest the pe structure for O and S, and the pa structure for Se and Te as stable forms. Steady-state and femtosecond-time resolved optical spectroscopy in toluene solution indicate that the O and S dyads emit from a CT state, whereas the Se and Te dyads emit from a tolan-localized state. The T1 state is tolan-localized in all cases, showing phosphorescence at 77 K. The heavy atom effect of chalcogens induces intersystem crossing from S1 to Tx, resulting in a decreasing S1 lifetime from 2.1 ns to 0.42 ps. The T1 states possess potential for singlet oxygen sensitization with a high quantum yield (ca. 40 %) for the O, S, and Se dyads. Radical cations exhibit spin density primarily localized at the heterocycle. EPR measurements and quasirelativistic DFT calculations reveal a very strong g-tensor anisotropy, supporting the pe structure for the S and Se derivatives.
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Affiliation(s)
- Paul Mentzel
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Marco Holzapfel
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Alexander Schmiedel
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Johanna Günther
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Maximilian Michel
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ivo Krummenacher
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Artur Wodyński
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Strasse des 17. Juni 135, 10623, Berlin, Germany
| | - Martin Kaupp
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Strasse des 17. Juni 135, 10623, Berlin, Germany
| | - Holger Braunschweig
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Christoph Lambert
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Center for Nanosystems Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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Dubroca T, Wang X, Mentink-Vigier F, Trociewitz B, Starck M, Parker D, Sherwin MS, Hill S, Krzystek J. Terahertz EPR spectroscopy using a 36-tesla high-homogeneity series-connected hybrid magnet. J Magn Reson 2023; 353:107480. [PMID: 37331305 DOI: 10.1016/j.jmr.2023.107480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/24/2023] [Accepted: 05/13/2023] [Indexed: 06/20/2023]
Abstract
Electron Paramagnetic Resonance (EPR) is a powerful technique to study materials and biological samples on an atomic scale. High-field EPR in particular enables extracting very small g-anisotropies in organic radicals and half-filled 3d and 4f metal ions such as MnII (3d5) or GdIII (4f7), and resolving EPR signals from unpaired spins with very close g-values, both of which provide high-resolution details of the local atomic environment. Before the recent commissioning of the high-homogeneity Series Connected Hybrid magnet (SCH, superconducting + resistive) at the National High Magnetic Field Laboratory (NHMFL), the highest-field, high-resolution EPR spectrometer available was limited to 25 T using a purely resistive "Keck" magnet at the NHMFL. Herein, we report the first EPR experiments performed using the SCH magnet capable of reaching the field of 36 T, corresponding to an EPR frequency of 1 THz for g = 2. The magnet's intrinsic homogeneity (25 ppm, that is 0.9 mT at 36 T over 1 cm diameter, 1 cm length cylinder) was previously established by NMR. We characterized the magnet's temporal stability (5 ppm, which is 0.2 mT at 36 T over one-minute, the typical acquisition time) using 2,2-diphenyl-1-picrylhydrazyl (DPPH). This high resolution enables resolving the weak g-anisotropy of 1,3-bis(diphenylene)-2-phenylallyl (BDPA), Δg = 2.5 × 10-4 obtained from measurements at 932 GHz and 33 T. Subsequently, we recorded EPR spectra at multiple frequencies for two GdIII complexes with potential applications as spin labels. We demonstrated a significant reduction in line broadening in Gd[DTPA], attributed to second order zero field splitting, and a resolution enhancement of g-tensor anisotropy for Gd[sTPATCN]-SL.
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Affiliation(s)
- Thierry Dubroca
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA.
| | - Xiaoling Wang
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Center for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, FL 32611, USA
| | - Frédéric Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Bianca Trociewitz
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Matthieu Starck
- Department of Chemistry, University of Durham, Durham DH13LE, UK
| | - David Parker
- Department of Chemistry, University of Durham, Durham DH13LE, UK
| | - Mark S Sherwin
- Department of Physics, University of California Santa Barbara, CA 93106, USA
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Center for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, FL 32611, USA; Department of Physics, Florida State University, Tallahassee FL 32306, USA
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA.
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Zhang T, Liu H, Gao F, Xu G, Wang K, Zhang X, Cao G, Wang T, Zhang J, Hu X, Li HO, Guo GP. Anisotropic g-Factor and Spin-Orbit Field in a Germanium Hut Wire Double Quantum Dot. Nano Lett 2021; 21:3835-3842. [PMID: 33914549 DOI: 10.1021/acs.nanolett.1c00263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Holes in nanowires have drawn significant attention in recent years because of the strong spin-orbit interaction, which plays an important role in constructing Majorana zero modes and manipulating spin-orbit qubits. Here, from the strongly anisotropic leakage current in the spin blockade regime for a double dot, we extract the full g-tensor and find that the spin-orbit field is in plane with an azimuthal angle of 59° to the axis of the nanowire. The direction of the spin-orbit field indicates a strong spin-orbit interaction along the nanowire, which may have originated from the interface inversion asymmetry in Ge hut wires. We also demonstrate two different spin relaxation mechanisms for the holes in the Ge hut wire double dot: spin-flip co-tunneling to the leads, and spin-orbit interaction within the double dot. These results help establish feasibility of a Ge-based quantum processor.
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Affiliation(s)
- Ting Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - He Liu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fei Gao
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Gang Xu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ke Wang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xin Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gang Cao
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ting Wang
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianjun Zhang
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Xuedong Hu
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, United States
| | - Hai-Ou Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guo-Ping Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Origin Quantum Computing Company Limited, Hefei, Anhui 230026, China
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Abstract
Fullerenes attract much attention in various scientific fields, but their electronic properties are still not completely understood. Here we report on a combined EPR and DFT study of the fullerene anion C60- in solid glassy environment. DFT calculations were used to characterize its electronic structure through spin density distribution and magnetic resonance parameters. The electron spin density is not uniformly distributed throughout the C60- cage but shows a pattern similar to PC61BM-. EPR spectroscopy reveals a rhombic g-tensor sensitive to the environment in the frozen glassy solutions, which can be rationalized by deformation of the fullerenes along low-frequency vibrational modes upon cooling. DFT modeling confirms that these deformations lead to variation in the C60- g values. The decrease in g-tensor anisotropy with sample annealing is related to the lessening of g-tensor strain upon temperature relaxation of the most distorted sites in the glassy state.
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Affiliation(s)
- Jens Niklas
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Kristy L. Mardis
- Department of Chemistry, Physics, and Engineering Studies, Chicago State University, Chicago, Illinois 60628, USA
| | - Oleg G. Poluektov
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
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Mardis KL, Webb JN, Holloway T, Niklas J, Poluektov OG. Electronic Structure of Fullerene Acceptors in Organic Bulk-Heterojunctions: A Combined EPR and DFT Study. J Phys Chem Lett 2015; 6:4730-5. [PMID: 26569578 PMCID: PMC4985179 DOI: 10.1021/acs.jpclett.5b02111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Organic photovoltaic (OPV) devices are a promising alternative energy source. Attempts to improve their performance have focused on the optimization of electron-donating polymers, while electron-accepting fullerenes have received less attention. Here, we report an electronic structure study of the widely used soluble fullerene derivatives PC61BM and PC71BM in their singly reduced state, that are generated in the polymer:fullerene blends upon light-induced charge separation. Density functional theory (DFT) calculations characterize the electronic structures of the fullerene radical anions through spin density distributions and magnetic resonance parameters. The good agreement of the calculated magnetic resonance parameters with those determined experimentally by advanced electron paramagnetic resonance (EPR) allows the validation of the DFT calculations. Thus, for the first time, the complete set of magnetic resonance parameters including directions of the principal g-tensor axes were determined. For both molecules, no spin density is present on the PCBM side chain, and the axis of the largest g-value lies along the PCBM molecular axis. While the spin density distribution is largely uniform for PC61BM, it is not evenly distributed for PC71BM.
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Affiliation(s)
- Kristy L Mardis
- Department of Chemistry and Physics, Chicago State University , Chicago, Illinois 60628, United States
| | - Jeremy N Webb
- Department of Chemistry and Physics, Chicago State University , Chicago, Illinois 60628, United States
| | - Tarita Holloway
- Department of Chemistry and Physics, Chicago State University , Chicago, Illinois 60628, United States
| | - Jens Niklas
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Oleg G Poluektov
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
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Pedersen MN, Hedegård ED, Kongsted J. Basis set error estimation for DFT calculations of electronic g-tensors for transition metal complexes. J Comput Chem 2014; 35:1809-14. [PMID: 25060998 DOI: 10.1002/jcc.23688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 06/30/2014] [Accepted: 07/02/2014] [Indexed: 11/10/2022]
Abstract
We present a detailed study of the basis set dependence of electronic g-tensors for transition metal complexes calculated using Kohn-Sham density functional theory. Focus is on the use of locally dense basis set schemes where the metal is treated using either the same or a more flexible basis set than used for the ligand sphere. The performance of all basis set schemes is compared to the extrapolated complete basis set limit results. Furthermore, we test the performance of the aug-cc-pVTZ-J basis set developed for calculations of NMR spin-spin and electron paramagnetic resonance hyperfine coupling constants. Our results show that reasonable results can be obtain when using small basis sets for the ligand sphere, and very accurate results are obtained when an aug-cc-pVTZ basis set or similar is used for all atoms in the complex.
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Affiliation(s)
- Morten N Pedersen
- Department of Physics Chemistry Pharmacy, University of Southern Denmark, DK-5230, Odense M, Denmark
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Liu W, Rumbley J, Englander SW, Wand AJ. Backbone and side-chain heteronuclear resonance assignments and hyperfine NMR shifts in horse cytochrome c. Protein Sci 2003; 12:2104-8. [PMID: 12931009 PMCID: PMC2324007 DOI: 10.1110/ps.03211303] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2003] [Revised: 06/05/2003] [Accepted: 05/08/2003] [Indexed: 10/27/2022]
Abstract
The [H26N, H33N] mutant of horse heart cytochrome c was expressed in E. coli during growth on isotopically enriched minimal media. Complete resonance assignments of both the diamagnetic reduced (spin zero) and paramagnetic oxidized (spin (1/2)) states of the protein were obtained using standard triple resonance and total correlation spectroscopy using the previously determined (1)H chemical shifts of the wild-type protein as a guide. The correspondence of chemical shifts between the wild type and the mutant protein is excellent, indicating that they have nearly identical structures. The expanded library of chemical shifts for both redox states in both proteins allowed the refinement of the electron spin g-tensor of the oxidized states. The g-tensors of the oxidized states of the wild-type and [H26N, H33N] mutant proteins are closely similar, indicating that the subtle details of the ligand fields are nearly identical. The refined g-tensors were then used to probe for redox-dependent structure change in the two proteins.
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Affiliation(s)
- Weixia Liu
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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