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Mizuno A, Matsuoka R, Mibu T, Kusamoto T. Luminescent Radicals. Chem Rev 2024; 124:1034-1121. [PMID: 38230673 DOI: 10.1021/acs.chemrev.3c00613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Organic radicals are attracting increasing interest as a new class of molecular emitters. They demonstrate electronic excitation and relaxation dynamics based on their doublet or higher multiplet spin states, which are different from those based on singlet-triplet manifolds of conventional closed-shell molecules. Recent studies have disclosed luminescence properties and excited state dynamics unique to radicals, such as highly efficient electron-photon conversion in OLEDs, NIR emission, magnetoluminescence, an absence of heavy atom effect, and spin-dependent and spin-selective dynamics. These are difficult or sometimes impossible to achieve with closed-shell luminophores. This review focuses on luminescent organic radicals as an emerging photofunctional molecular system, and introduces the material developments, fundamental properties including luminescence, and photofunctions. Materials covered in this review range from monoradicals, radical oligomers, and radical polymers to metal complexes with radical ligands demonstrating radical-involved emission. In addition to stable radicals, transiently formed radicals generated in situ by external stimuli are introduced. This review shows that luminescent organic radicals have great potential to expand the chemical and spin spaces of luminescent molecular materials and thus broaden their applicability to photofunctional systems.
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Affiliation(s)
- Asato Mizuno
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Ryota Matsuoka
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, HayamaKanagawa 240-0193, Japan
| | - Takuto Mibu
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Tetsuro Kusamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, HayamaKanagawa 240-0193, Japan
- JST-PRESTO, 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
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Mouchel Dit Leguerrier D, Barré R, Ruet Q, Frachet V, Imbert D, Thomas F, Molloy JK. Symmetric CEST-active lanthanide complexes for redox monitoring. Dalton Trans 2022; 51:18400-18408. [PMID: 36415954 DOI: 10.1039/d2dt02776c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two symmetric ligands harbouring two TEMPO radicals and two functionalized acetamide arms (R = OMe (L1), CF3 (L2)) were prepared and chelated to lanthanide ions (EuIII, YbIII for both L1 and L2, DyIII for L1). Luminescence measurements on the europium complexes support the coordination of a single water molecule. The TEMPO arms are magnetically interacting in L1 (and its complexes) but not in L2. The TEMPO moieties can be reversibly oxidized into an oxoammonium (0.33-0.36 V vs. Fc+/Fc) or reduced into a hydroxylamine (ill-defined redox wave, reduction by ascorbate), which are both diamagnetic. The europium complexes [Eu(L1)]3+ and [Eu(L2)]3+ in their hydroxylamine form exhibit a temperature dependent CEST effect, which is maximal at 25 °C (30%) and 37 °C (12%), respectively. The CEST activity is dramatically reduced in the corresponding nitroxide forms due to the paramagnetism of the ligand. The europium complexes show no cytotoxicity against M21 cell lines over long incubation times (72 h) at high concentration (40 μM).
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Affiliation(s)
| | - Richard Barré
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France.
| | - Quentin Ruet
- Institute for Advanced Biosciences, INSERM U1209, UMR CNRS 5309, Grenoble Alpes University, 38700 La Tronche, France.,EPHE, PSL Research University, 75014 Paris, France
| | - Véronique Frachet
- Institute for Advanced Biosciences, INSERM U1209, UMR CNRS 5309, Grenoble Alpes University, 38700 La Tronche, France.,EPHE, PSL Research University, 75014 Paris, France
| | - Daniel Imbert
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-LCBM, 38000 Grenoble, France
| | - Fabrice Thomas
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France.
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New TEMPO-Appended 2,2'-Bipyridine-Based Eu(III), Tb(III), Gd(III) and Sm(III) Complexes: Synthesis, Photophysical Studies and Testing Photoluminescence-Based Bioimaging Abilities. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238414. [PMID: 36500504 PMCID: PMC9739109 DOI: 10.3390/molecules27238414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/05/2022]
Abstract
Linked to Alzheimer's disease (AD), amyloids and tau-protein are known to contain a large number of cysteine (Cys) residues. In addition, certain levels of some common biogenic thiols (cysteine (Cys), homocysteine (Hcy), glutathione (GSH), etc.) in biological fluids are closely related to AD as well as other diseases. Therefore, probes with a selective interaction with the above-mentioned thiols can be used for the monitoring and visualizing changes of (bio)thiols in the biological fluids as well as in the brain of animal models of Alzheimer's disease. In this study, new Eu(III), Tb(III), Gd(III) and Sm(III) complexes of 2,2'-bipyridine ligands containing TEMPO fragments as receptor units for (bio)thiols are reported. The presence of free radical fragments of the ligand in the complexes was proved by using the electronic paramagnetic resonance (EPR) method. Among all the complexes, the Eu(III) complex turned out to be the most promising one as luminescence- and spin-probe for the detection of biogenic thiols. The EPR and fluorescent titration methods showed the interaction of the resulting complex with free Cys and GSH in solution. To study the practical applicability of the probes for the monitoring of AD in-vivo, by using the above-mentioned Eu(III)-based probe, the staining of the brain of mice with amyloidosis and Vero cell cultures supplemented with the cysteine-enriched medium was studied as well as the fluorescence titration of Bovine Serum Albumin, BSA (as the model for the thiol moieties containing protein), was carried out. Based on the results of fluorescence titration, the formation of a non-covalent inclusion complex between the above-mentioned Eu(III) complex and BSA was suggested.
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Gálico DA, Mazali IO, Sigoli FA. Bifunctional Temperature and Oxygen Dual Probe Based on Anthracene and Europium Complex Luminescence. Int J Mol Sci 2022; 23:ijms232314526. [PMID: 36498852 PMCID: PMC9740382 DOI: 10.3390/ijms232314526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/17/2022] [Accepted: 11/20/2022] [Indexed: 11/23/2022] Open
Abstract
In this work, we synthesized a polydimethylsiloxane membrane containing two emitter groups chemically attached to the membrane structure. For this, we attached the anthracene group and the [Eu(bzac)3] complex as blue and red emitters, respectively, in the matrix via hydrosilylation reactions. The synthesized membrane can be used as a bifunctional temperature and oxygen ratiometric optical probe by analyzing the effects that temperature changes and oxygen levels produce on the ratio of anthracene and europium(III) emission components. As a temperature probe, the system is operational in the 203-323 K range, with an observed maximum relative sensitivity of 2.06% K-1 at 290 K and temperature uncertainties below 0.1 K over all the operational range. As an oxygen probe, we evaluated the ratiometric response at 25, 30, 35, and 40 °C. These results show an interesting approach to obtaining bifunctional ratiometric optical probes and also suggest the presence of an anthracene → europium(III) energy transfer, even though there is no chemical bonding between species.
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Affiliation(s)
- Diogo Alves Gálico
- Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, Campinas 13083-970, Sao Paulo, Brazil
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Correspondence: (D.A.G.); (F.A.S.)
| | - Italo Odone Mazali
- Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, Campinas 13083-970, Sao Paulo, Brazil
| | - Fernando Aparecido Sigoli
- Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, Campinas 13083-970, Sao Paulo, Brazil
- Correspondence: (D.A.G.); (F.A.S.)
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Barré R, Mouchel Dit Leguerrier D, Ruet Q, Fedele L, Imbert D, Martel-Frachet V, Fries PH, Molloy JK, Thomas F. Lanthanide complexes (GdIII and EuIII) based on a DOTA-TEMPO platform for redox monitoring via relaxivity. Chem Asian J 2022; 17:e202200544. [PMID: 35796463 PMCID: PMC9544908 DOI: 10.1002/asia.202200544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/06/2022] [Indexed: 11/27/2022]
Abstract
Three lanthanide complexes (Ln=Gd, Eu) based on a DO3 A ([Ln(L1)]) or DO2 A ([Ln(L2–3)]+) platform appended by a redox active TEMPO‐based arm were prepared. Complex [Ln(L2)]+ shows an alkyne arm, offering the possibility of postfunctionalization by click reaction to yield [Ln(L3)]+. The complexes demonstrate a redox response whereby the hydroxylamine, nitroxide and oxoammonium forms of the arm can be obtained in turn. Luminescence measurements on the europium complexes support an octadentate (L1, L3) or heptadentate (L2) chelation by the ligand, with one water molecule in the inner coordination sphere. The relaxivity was determined from 20 kHz to 30 MHz by fast‐field cycling NMR. The three GdIII complexes under their hydroxylamine form [Gd(L1)] and [Gd(L2–3)]+ show r1 values of 7.0, 5.1 and 5.0 mM−1 s−1 (30 KHz), which increase to 8.8, 5.5 and 6.1 mM−1 s−1 in the nitroxide form. The radical complexes are not toxic against M21 cell lines, at least up to 40 μM. By using EPR spectroscopy we establish that they do not penetrate the cells with the exception of [Eu(L2)]+.
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Affiliation(s)
- Richard Barré
- Université Grenoble Alpes: Universite Grenoble Alpes, Department of molecular chemistry, FRANCE
| | | | - Quentin Ruet
- Université Grenoble Alpes: Universite Grenoble Alpes, Department of molecular chemistry, FRANCE
| | - Lionel Fedele
- CEA lRlG: Commissariat a l'energie atomique et aux energies alternatives lnstitut de Recherche Interdisciplinaire de Grenoble, SYMMES, FRANCE
| | - Daniel Imbert
- CEA lRlG: Commissariat a l'energie atomique et aux energies alternatives lnstitut de Recherche Interdisciplinaire de Grenoble, LCBM, FRANCE
| | | | - Pascal H Fries
- CEA lRlG: Commissariat a l'energie atomique et aux energies alternatives lnstitut de Recherche Interdisciplinaire de Grenoble, SYMMES, FRANCE
| | - Jennifer K Molloy
- Université Grenoble Alpes: Universite Grenoble Alpes, Department of molecular chemistry, FRANCE
| | - Fabrice Thomas
- Université Grenoble Alpes: Universite Grenoble Alpes, Department of molecular chemistry, 301 rue de la Chimie, CS 40700, 38058, Grenoble, cedex 9, FRANCE
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Mouchel Dit Leguerrier D, Barré R, Molloy J, Thomas F. Lanthanide complexes as redox and ROS/RNS probes: A new paradigm that makes use of redox-reactive and redox non-innocent ligands. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Mouchel Dit Leguerrier D, Barré R, Ruet Q, Imbert D, Philouze C, Fries PH, Martel-Frachet V, Molloy JK, Thomas F. Lanthanide complexes of DOTA-nitroxide conjugates for redox imaging: spectroelectrochemistry, CEST, relaxivity, and cytotoxicity. Dalton Trans 2021; 50:10826-10837. [PMID: 34291274 DOI: 10.1039/d1dt01628h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The lanthanide(iii) complexes (Gd, Eu, Dy, and Yb) of DOTA tris(amide) and bis(amide) derivatives (L1 and L2) featuring one redox active TEMPO arm were prepared. Ligand L2 harbours an alkyne fragment for further functionalization. The X-ray crystal structure of ligand L2 in complexation with Na+ was solved. The complexes showed in their CV one oxidation wave (0.26-0. 34 V vs. Fc+/Fc) due to an oxoammonium/nitroxide redox couple and a broad reduction corresponding to the nitroxide/hydroxylamine system. The Eu complexes demonstrated the presence of one water molecule in their coordination sphere. The nitroxide complexes were characterized by EPR spectroscopy, showing the typical 3-line pattern in the high temperature regime, which is quenched upon the addition of ascorbate (reduction into hydroxylamine). In their nitroxide form, the complexes show essentially no CEST peak. Conversely, the reduced complexes demonstrate a 12% CEST peak at 51 ppm, corresponding to the metal bound water molecule. Fast exchange precluded the CEST activity for the amide protons. All the complexes proved to be essentially non-toxic for M21 cells at concentrations up to 50 μM.
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Affiliation(s)
| | - R Barré
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France.
| | - Q Ruet
- Institute for Advanced Biosciences, INSERM U1209, UMR CNRS 5309, Grenoble Alpes University, 38700 La Tronche, France
| | - D Imbert
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-LCBM, 38000 Grenoble, France
| | - C Philouze
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France.
| | - P H Fries
- Univ. Grenoble Alpes, CEA, CNRS, IRIG-LCBM, 38000 Grenoble, France
| | - V Martel-Frachet
- Institute for Advanced Biosciences, INSERM U1209, UMR CNRS 5309, Grenoble Alpes University, 38700 La Tronche, France and EPHE, PSL Research University, 75014 Paris, France
| | - J K Molloy
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France.
| | - F Thomas
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France.
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Galaup C, Picard C, Couderc F, Gilard V, Collin F. Luminescent lanthanide complexes for reactive oxygen species biosensing and possible application in Alzheimer's diseases. FEBS J 2021; 289:2516-2539. [PMID: 33811448 DOI: 10.1111/febs.15859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/19/2021] [Accepted: 04/01/2021] [Indexed: 12/19/2022]
Abstract
Histopathological hallmarks of Alzheimer's disease (AD) are intracellular neurofibrillary tangles and extracellular formation of senile plaques composed of the aggregated amyloid-beta peptide along with metal ions (copper, iron or zinc). In addition, oxidative stress is considered as an important factor in the etiology of AD and a multitude of metalloproteins and transporters is affected, leading to metal ion misregulation. Redox-active metal ions (e.g., copper) can catalyze the production of reactive oxygen species (ROS) in the presence of molecular oxygen and a reductant such as ascorbate. The ROS thus produced, in particular the hydroxyl radical which is the most reactive one, may contribute to oxidative stress conditions. Thus, detecting ROS in vivo or in biological models of AD is of interest for better understanding AD etiology. The use of biocompatible and highly specific and sensitive probes is needed for such a purpose, since ROS are transient species whose steady-state concentrations are very low. Luminescent lanthanide complexes are sensitive probes that can meet these criteria. The present review focuses on the recent advances in the use of luminescent lanthanide complexes for ROS biosensing. It shows why the use of luminescent lanthanide complexes is of particular interest for selectively detecting ROS ( O 2 · - , HO• , 1 O2 , H2 O2 , etc.) in biological samples in the µM-nM range. It particularly focuses on the most recent strategies and discusses what could be expected with the use of luminescent lanthanide complexes for better understanding some of the molecular mechanisms underlying the development of Alzheimer's disease.
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Affiliation(s)
- Chantal Galaup
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique (SPCMIB), Université Paul Sabatier-Toulouse III/CNRS (UMR5068), France
| | - Claude Picard
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique (SPCMIB), Université Paul Sabatier-Toulouse III/CNRS (UMR5068), France
| | - François Couderc
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, France
| | - Véronique Gilard
- Laboratoire de Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique (SPCMIB), Université Paul Sabatier-Toulouse III/CNRS (UMR5068), France
| | - Fabrice Collin
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, France
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Li M, Wang C, Wang D, Li J. Structure-Dependent Photoluminescence of Europium(III) Coordination Oligomeric Silsesquioxane: Synthesis and Mechanism. ACS OMEGA 2021; 6:227-238. [PMID: 33458475 PMCID: PMC7807471 DOI: 10.1021/acsomega.0c04365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/18/2020] [Indexed: 05/08/2023]
Abstract
The coordination environment of Eu3+ is a crucial factor in the optical performance of the complex. Herein, a new kind of oligomeric silsesquioxane was employed to improve the coordination environment of central ions, the luminescence intensity of which was greatly enhanced with an efficient emission peak at 619 nm. More importantly, the photoluminescent properties of the product will be altered because of the formation of the Si-O-Si structure. The relevant mechanism has also been investigated and proposed by a series of characterization analyses. Additionally, the fluorescence lifetime, intrinsic quantum yield, and energy transfer efficiency were calculated. In addition, the observed trend of Judd-Ofelt intensity parameters was used to justify the coordination environment of Eu3+ ions. The experimental results reveal that the sol-gel reaction of the ligands can effectively promote intramolecular energy transfer. In addition, we introduced four theory modules of ligands (LSi, LSi-1, LSi-2, and LSi-3) with certain rules of formation of Si-O-Si, and density functional theory (DFT) and time-dependent DFT (TD-DFT) were used to explore their excited electron transfer process and their electronic absorption spectra, combined with Marcus theory. The calculated results show that the sol-gel reaction will induce the separation of the distribution of excited holes and electrons, leading to an efficient charge-transfer (CT) process. The predictable results were in good accordance with the experimental findings. Consequently, the sol-gel reaction occurring among ligands will be attributed to an efficient CT process, leading to a strong luminescence intensity, as observed experimentally.
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Affiliation(s)
- Ming Li
- Key
Laboratory of Bio-based Material Science and Technology of Ministry
of Education, Northeast Forestry University, Hexing Road 26, Harbin 150040, P. R. China
- Material
Science and Engineering College Northeast Forestry University, Hexing Road 26, Harbin 150040, P. R. China
| | - Chengyu Wang
- Key
Laboratory of Bio-based Material Science and Technology of Ministry
of Education, Northeast Forestry University, Hexing Road 26, Harbin 150040, P. R. China
| | - Di Wang
- Key
Laboratory of Bio-based Material Science and Technology of Ministry
of Education, Northeast Forestry University, Hexing Road 26, Harbin 150040, P. R. China
| | - Jian Li
- Key
Laboratory of Bio-based Material Science and Technology of Ministry
of Education, Northeast Forestry University, Hexing Road 26, Harbin 150040, P. R. China
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Kunert R, Philouze C, Berthiol F, Jarjayes O, Storr T, Thomas F. Distorted copper(ii) radicals with sterically hindered salens: electronic structure and aerobic oxidation of alcohols. Dalton Trans 2020; 49:12990-13002. [PMID: 32909589 DOI: 10.1039/d0dt02524k] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The sterically hindered salen ligands featuring biphenyl and tetramethyl putrescine linkers were synthesized and chelated to copper. The resulting complexes CuLbp,tBu, CuLbp,OMe, CuLpu,tBu and CuLpu,OMe were structurally characterized, showing a significanty tetrahedrally distorted metal center. The complexes show two reversible oxidation waves in the range 0.2 to 0.8 V vs. Fc+/Fc. A further reduction wave is detected in the range -1.4 to -1.7 V vs. Fc+/Fc. It is reversible for CuLbp,tBu and CuLbp,OMe and assigned to the CuII/CuI redox couple. One-electron oxidation of CuLbp,OMe, CuLpu,tBu and CuLpu,OMe was performed chemically and electrochemically. It is accompanied by a quenching of the EPR resonances. Phenoxyl radical formation was established by X-Ray diffraction on the cations [CuLbp,OMe]+ and [CuLpu,OMe]+, whereby the coordination sphere is elongated upon oxidation with quinoidal distributions of bond distances. The cations exhibit a NIR band of moderate intensity in their optical spectrum, supporting their classification as class II mixed-valent radical species according to the Robin Day classification. The proposed electronic structures are supported by DFT calculations. The cations [CuLbp,OMe]+, [CuLpu,tBu]+ and [CuLpu,OMe]+ were active towards aerobic oxidation of the unactivated alcohol 2-phenylethanol, with TON numbers up to 58 within 3 h.
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Affiliation(s)
- R Kunert
- Univ. Grenoble Alpes, CNRS, DCM, 38000 Grenoble, France.
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