1
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Panariti D, Conron SM, Zhang J, Wasielewski MR, Di Valentin M, Tait CE. Control of excitation selectivity in pulse EPR on spin-correlated radical pairs with shaped pulses. Phys Chem Chem Phys 2024; 26:3842-3856. [PMID: 38221856 DOI: 10.1039/d3cp06009h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Spin-correlated radical pairs generated by photoinduced electron transfer are characterised by a distinctive spin polarisation and a unique behaviour in pulse electron paramagnetic resonance (EPR) spectroscopy. Under non-selective excitation, an out-of-phase echo signal modulated by the dipolar and exchange coupling interactions characterising the radical pair is observed and allows extraction of geometric information in the two-pulse out-of-phase electron spin echo envelope modulation (ESEEM) experiment. The investigation of the role of spin-correlated radical pairs in a variety of biological processes and in the fundamental mechanisms underlying device function in optoelectronics, as well as their potential use in quantum information science, relies on the ability to precisely address and manipulate the spins using microwave pulses. Here, we explore the use of shaped pulses for controlled narrowband selective and broadband non-selective excitation of spin-correlated radical pairs in two model donor-bridge-acceptor triads, characterised by different spectral widths, at X- and Q-band frequencies. We demonstrate selective excitation with close to rectangular excitation profiles using BURP (band-selective, uniform response, pure-phase) pulses and complete non-selective excitation of both spins of the radical pair using frequency-swept chirp pulses. The use of frequency-swept pulses in out-of-phase ESEEM experiments enables increased modulation depths and, combined with echo transient detection and Fourier transformation, correlation of the dipolar frequencies with the EPR spectrum and therefore the potential to extract additional information on the donor-acceptor pair geometry.
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Affiliation(s)
- Daniele Panariti
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy
| | - Sarah M Conron
- Department of Chemistry, Applied Physics Program, and Center for Molecular Quantum Transduction, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Jinyuan Zhang
- Department of Chemistry, Applied Physics Program, and Center for Molecular Quantum Transduction, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Michael R Wasielewski
- Department of Chemistry, Applied Physics Program, and Center for Molecular Quantum Transduction, Northwestern University, Evanston, Illinois 60208-3113, USA
| | | | - Claudia E Tait
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK.
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2
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Endeward B, Bretschneider M, Trenkler P, Prisner TF. Implementation and applications of shaped pulses in EPR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2023; 136-137:61-82. [PMID: 37716755 DOI: 10.1016/j.pnmrs.2023.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 04/12/2023] [Accepted: 04/26/2023] [Indexed: 09/18/2023]
Abstract
In this review, we describe the application of shaped pulses for EPR spectroscopy. Pulses generated by fast arbitrary waveform generators are mostly used in the field of EPR spectroscopy for broadband (200 MHz-1 GHz) excitation of paramagnetic species. The implementation and optimization of such broadband pulses in existing EPR spectrometers, often designed and optimized for short rectangular microwave pulses, is demanding. Therefore, a major part of this review will describe in detail the implementation, testing and optimization of shaped pulses in existing EPR spectrometers. Additionally, we review applications using such pulses for broadband inversion of longitudinal magnetization as well as for the creation and manipulation of transverse magnetization in the field of dipolar and hyperfine EPR spectroscopy. They demonstrate the great potential of shaped pulses to improve the performance of pulsed EPR experiments. We give a brief theoretical description of shaped pulses and their limitations, especially for adiabatic pulses, most often used in EPR. We believe that this review can on the one hand be of practical use to EPR groups starting to work with such pulses, and on the other hand give readers an overview of the state of the art of shaped pulse applications in EPR spectroscopy.
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Affiliation(s)
- Burkhard Endeward
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Matthias Bretschneider
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Paul Trenkler
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438 Frankfurt am Main, Germany.
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3
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Klose D, Vemulapalli SPB, Richman M, Rudnick S, Aisha V, Abayev M, Chemerovski M, Shviro M, Zitoun D, Majer K, Wili N, Goobes G, Griesinger C, Jeschke G, Rahimipour S. Cu 2+-Induced self-assembly and amyloid formation of a cyclic D,L-α-peptide: structure and function. Phys Chem Chem Phys 2022; 24:6699-6715. [PMID: 35234757 DOI: 10.1039/d1cp05415e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In a wide spectrum of neurodegenerative diseases, self-assembly of pathogenic proteins to cytotoxic intermediates is accelerated by the presence of metal ions such as Cu2+. Only low concentrations of these early transient oligomeric intermediates are present in a mixture of species during fibril formation, and hence information on the extent of structuring of these oligomers is still largely unknown. Here, we investigate dimers as the first intermediates in the Cu2+-driven aggregation of a cyclic D,L-α-peptide architecture. The unique structural and functional properties of this model system recapitulate the self-assembling properties of amyloidogenic proteins including β-sheet conformation and cross-interaction with pathogenic amyloids. We show that a histidine-rich cyclic D,L-α-octapeptide binds Cu2+ with high affinity and selectivity to generate amyloid-like cross-β-sheet structures. By taking advantage of backbone amide methylation to arrest the self-assembly at the dimeric stage, we obtain structural information and characterize the degree of local order for the dimer. We found that, while catalytic amounts of Cu2+ promote aggregation of the peptide to fibrillar structures, higher concentrations dose-dependently reduce fibrillization and lead to formation of spherical particles, showing self-assembly to different polymorphs. For the initial self-assembly step to the dimers, we found that Cu2+ is coordinated on average by two histidines, similar to self-assembled peptides, indicating that a similar binding interface is perpetuated during Cu2+-driven oligomerization. The dimer itself is found in heterogeneous conformations that undergo dynamic exchange, leading to the formation of different polymorphs at the initial stage of the aggregation process.
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Affiliation(s)
- Daniel Klose
- Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland.
| | - Sahithya Phani Babu Vemulapalli
- NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany. .,Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, 26129 Oldenburg, Germany
| | - Michal Richman
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Safra Rudnick
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel. .,Bar-Ilan Institute for Technology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Vered Aisha
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Meital Abayev
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Marina Chemerovski
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Meital Shviro
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel. .,Bar-Ilan Institute for Technology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - David Zitoun
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel. .,Bar-Ilan Institute for Technology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Katharina Majer
- Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland.
| | - Nino Wili
- Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland.
| | - Gil Goobes
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Christian Griesinger
- NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland.
| | - Shai Rahimipour
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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Verstraete JB, Myers WK, Foroozandeh M. Chirped ordered pulses for ultra-broadband ESR spectroscopy. J Chem Phys 2021; 154:094201. [PMID: 33685137 DOI: 10.1063/5.0038511] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recently, applications of swept-frequency pulses proved to be a useful approach to circumvent the problem of limited excitation bandwidth in pulsed ESR posed by conventional pulses. Here, we present a chirped excitation sequence, CHirped ORdered pulses for Ultra-broadband Spectroscopy (CHORUS), for ultra-broadband ESR spectroscopy. It will be demonstrated that the application of this sequence can address the problems of excitation non-uniformity and sensitivity to instrumental instabilities to a greater extent compared to the current state of the art. This sequence is highly promising for finding applications beyond single excitation in many ESR experiments. Theoretical and experimental results for the proposed method are presented along with calibration strategies for experimental implementation.
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Affiliation(s)
- Jean-Baptiste Verstraete
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - William K Myers
- Centre for Advanced ESR, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Mohammadali Foroozandeh
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
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Ashuiev A, Allouche F, Wili N, Searles K, Klose D, Copéret C, Jeschke G. Molecular and supported Ti(iii)-alkyls: efficient ethylene polymerization driven by the π-character of metal-carbon bonds and back donation from a singly occupied molecular orbital. Chem Sci 2020; 12:780-792. [PMID: 34163812 PMCID: PMC8178971 DOI: 10.1039/d0sc04436a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
While Ti(iii) alkyl species are the proposed active sites in Ziegler–Natta ethylene polymerization catalysts, the corresponding well-defined homogeneous catalysts are not known. We report that well-defined neutral β-diiminato Ti(iii) alkyl species, namely [Ti(nacnac)(CH2tBu)2] and its alumina-grafted derivative [(AlsO)Ti(nacnac)(CH2tBu)], are active towards ethylene polymerization at moderate pressures and temperatures and possess an electron configuration well-adapted to insertion of ethylene. Advanced EPR spectroscopy showed that ethylene insertion into a Ti(iii)–C bond takes place during polymerization from Ti(nacnac)(CH2tBu)2. A combination of pulsed EPR spectroscopy and DFT calculations, based on a crystal structure of [Ti(nacnac)(CH2tBu)2], enabled us to reveal details about the structure and electronic configurations of both molecular and surface-grafted species. For both compounds, the α-agostic C–H interaction, which involves the singly occupied molecular orbital, indicates a π character of the metal–carbon bond; this π character is enhanced upon ethylene coordination, leading to a nearly barrier-less C2H4 insertion into Ti(iii)–C bonds after this first step. During coordination, back donation from the SOMO to the π*(C2H4) occurs, leading to stabilization of π-ethylene complexes and to a significant lowering of the overall energy of the C2H4 insertion transition state. In d1 alkyl complexes, ethylene insertion follows an original “augmented” Cossee–Arlman mechanism that involves the delocalization of unpaired electrons between the SOMO, π*(C2H4) and σ*(Ti–C) in the transition state, which further favors ethylene insertion. All these factors facilitate ethylene polymerization on Ti(iii) neutral alkyl species and make d1 alkyl complexes potentially more effective polymerization catalysts than their d0 analogues. Ti(iii) alkyl species polymerize ethylene via an original mechanism, which involves back donation to the π*(C2H4) and a delocalization of the unpaired electron in the transition state of C2H4 insertion into the partially alkylidenic Ti(iii)–C bond.![]()
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Affiliation(s)
- Anton Ashuiev
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1-5 CH-8093 Zürich Switzerland
| | - Florian Allouche
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1-5 CH-8093 Zürich Switzerland
| | - Nino Wili
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1-5 CH-8093 Zürich Switzerland
| | - Keith Searles
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1-5 CH-8093 Zürich Switzerland
| | - Daniel Klose
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1-5 CH-8093 Zürich Switzerland
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1-5 CH-8093 Zürich Switzerland
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1-5 CH-8093 Zürich Switzerland
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6
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Foroozandeh M. Spin dynamics during chirped pulses: applications to homonuclear decoupling and broadband excitation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 318:106768. [PMID: 32917298 DOI: 10.1016/j.jmr.2020.106768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 05/27/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
Swept-frequency pulses have found applications in a wide range of areas including spectroscopic techniques where efficient control of spins is required. For many of these applications, a good understanding of the evolution of spin systems during these pulses plays a vital role, not only in describing the mechanism of techniques, but also in enabling new methodologies. In magnetic resonance spectroscopy, broadband inversion, refocusing, and excitation using these pulses are among the most used applications in NMR, ESR, MRI, and in vivo MRS. In the present survey, a general expression for chirped pulses will be introduced, and some numerical approaches to calculate the spin dynamics during chirped pulses via solutions of the well-known Liouville-von Neumann equation and the lesser-explored Wei-Norman Lie algebra along with comprehensive examples are presented. In both cases, spin state trajectories are calculated using the solution of differential equations. Additionally, applications of the proposed methods to study the spin dynamics during the PSYCHE pulse element for broadband homonuclear decoupling and the CHORUS sequence for broadband excitation will be presented.
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7
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Ramirez Cohen M, Feintuch A, Goldfarb D, Vega S. Study of electron spectral diffusion process under DNP conditions by ELDOR spectroscopy focusing on the 14N solid effect. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2020; 1:45-57. [PMID: 37904885 PMCID: PMC10500736 DOI: 10.5194/mr-1-45-2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/26/2020] [Indexed: 11/01/2023]
Abstract
Electron spectral diffusion (eSD) plays an important role in solid-state, static dynamic nuclear polarization (DNP) with polarizers that have inhomogeneously broadened EPR spectra, such as nitroxide radicals. It affects the electron spin polarization gradient within the EPR spectrum during microwave irradiation and thereby determines the effectiveness of the DNP process via the so-called indirect cross-effect (iCE) mechanism. The electron depolarization profile can be measured by electron-electron double resonance (ELDOR) experiments, and a theoretical framework for deriving eSD parameters from ELDOR spectra and employing them to calculate DNP profiles has been developed. The inclusion of electron depolarization arising from the 14 N solid effect (SE) has not yet been taken into account in this theoretical framework and is the subject of the present work. The 14 N SE depolarization was studied using W-band ELDOR of a 0.5 mM TEMPOL solution, where eSD is negligible, taking into account the hyperfine interaction of both 14 N and 1 H nuclei, the long microwave irradiation applied under DNP conditions, and electron and nuclear relaxation. The results of this analysis were then used in simulations of ELDOR spectra of 10 and 20 mM TEMPOL solutions, where eSD is significant using the eSD model and the SE contributions were added ad hoc employing the 1 H and 14 N frequencies and their combinations, as found from the analysis of the 0.5 mM sample. This approach worked well for the 20 mM solution, where a good fit for all ELDOR spectra recorded along the EPR spectrum was obtained and the inclusion of the 14 N SE mechanism improved the agreement with the experimental spectra. For the 10 mM solution, simulations of the ELDOR spectra recorded along the g z position gave a lower-quality fit than for spectra recorded in the center of the EPR spectrum. This indicates that the simple approach we used to describe the 14 N SE is limited when its contribution is relatively high as the anisotropy of its magnetic interactions was not considered explicitly.
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Affiliation(s)
- Marie Ramirez Cohen
- Department of Chemical and Biological Physics, Weizmann Institute of Science,
Rehovot, Israel
| | - Akiva Feintuch
- Department of Chemical and Biological Physics, Weizmann Institute of Science,
Rehovot, Israel
| | - Daniella Goldfarb
- Department of Chemical and Biological Physics, Weizmann Institute of Science,
Rehovot, Israel
| | - Shimon Vega
- Department of Chemical and Biological Physics, Weizmann Institute of Science,
Rehovot, Israel
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8
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A trade-off for covalent and intercalation binding modes: a case study for Copper (II) ions and singly modified DNA nucleoside. Sci Rep 2019; 9:12602. [PMID: 31467417 PMCID: PMC6715747 DOI: 10.1038/s41598-019-48935-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 07/29/2019] [Indexed: 12/03/2022] Open
Abstract
Selective binding to nucleic acids and, more generally, to biopolymers, very often requires at a minimum the presence of specific functionalities and precise spatial arrangement. DNA can fold into defined 3D structures upon binding to metal centers and/or lanthanides. Binding efficiency can be boosted by modified nucleosides incorporated into DNA sequences. In this work the high selectivity of modified nucleosides towards copper (II) ions, when used in the monomeric form, is unexpectedly and drastically reduced upon being covalently attached to the DNA sequence in single-site scenario. Surprisingly, such selectivity is partially retained upon non-covalent (i.e. intercalation) mixture formed by native DNA duplex and a nucleoside in the monomeric form. Exploiting the electron spin properties of such different and rich binding mode scenarios, 1D/2D pulsed EPR experiments have been used and tailored to differentiate among the different modes. An unusual correlation of dispersion of hyperfine couplings and strength of the binding mode(s) is described.
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9
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Hetzke T, Bowen AM, Vogel M, Gauger M, Suess B, Prisner TF. Binding of tetracycline to its aptamer determined by 2D-correlated Mn 2+ hyperfine spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 303:105-114. [PMID: 31039520 DOI: 10.1016/j.jmr.2019.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/16/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
The tetracycline-binding RNA aptamer (TC-aptamer) binds its cognate ligand the antibiotic tetracycline (TC) via a Mg2+ or Mn2+ ion with high affinity at high divalent metal ion concentrations (KD=800pM, ⩾10 mM). These concentrations lie above the physiological divalent metal ion concentration of ca. 1 mM and it is known from literature, that the binding affinity decreases upon decreasing the divalent metal ion concentration. This work uses a Mn2+ concentration of 1 mM and 1D-hyperfine experiments reveal two pronounced 31P couplings from the RNA besides the 13C signal of 13C-labeled TC. From these 1D-hyperfine data alone, however, no conclusions can be drawn on the binding of TC. Either TC may bind via Mn2+ to the aptamer or TC may form a free Mn-TC complex and some Mn2+ also binds to the aptamer. In this work, we show using 2D-correlated hyperfine spectroscopy at Q-band frequencies (34 GHz), that the 13C and 31P signals can be correlated; thus arising from a single species. We use THYCOS (triple hyperfine correlation spectroscopy) and 2D ELDOR-detected NMR (2D electron electron double resonance detected NMR) for this purpose showing that they are suitable techniques to correlate two different nuclear spin species (13C and 31P) on two different molecules (RNA and TC) to the same electron spin (Mn2+). Out of the two observed 31P-hyperfine couplings, only one shows a clear correlation to 13C. Although THYCOS and 2D EDNMR yield identical results, 2D EDNMR is far more sensitive. THYCOS spectra needed a time factor of ×20 in comparison to 2D EDNMR to achieve a comparable signal-to-noise.
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Affiliation(s)
- Thilo Hetzke
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Alice M Bowen
- Center for Advanced Electron Spin Resonance (CAESR), Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Marc Vogel
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Maximilian Gauger
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Beatrix Suess
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany.
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10
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Wili N, Richert S, Limburg B, Clarke SJ, Anderson HL, Timmel CR, Jeschke G. ELDOR-detected NMR beyond hyperfine couplings: a case study with Cu(ii)-porphyrin dimers. Phys Chem Chem Phys 2019; 21:11676-11688. [DOI: 10.1039/c9cp01760g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pulse EPR method ELDOR-detected NMR gives information about electron–electron couplings in Cu(ii) porphyrin dimers.
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Affiliation(s)
- Nino Wili
- Laboratorium für Physikalische Chemie
- ETH Zürich
- 8093 Zürich
- Switzerland
| | - Sabine Richert
- Centre for Advanced Electron Spin Resonance (CÆSR)
- University of Oxford
- Oxford
- UK
| | - Bart Limburg
- Chemistry Research Laboratory
- University of Oxford
- Oxford
- UK
| | | | | | | | - Gunnar Jeschke
- Laboratorium für Physikalische Chemie
- ETH Zürich
- 8093 Zürich
- Switzerland
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