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Kostin GA, Tolstikov SE, Kuratieva NV, Nadolinny VA, Ovcharenko VI. FIRST EXAMPLE OF RUTHENIUM NITROSO COMPLEXES WITH A NITROXYL RADICAL AS A LIGAND. J STRUCT CHEM+ 2023. [DOI: 10.1134/s0022476623020014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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Tretyakov EV, Ovcharenko VI, Terent'ev AO, Krylov IB, Magdesieva TV, Mazhukin DG, Gritsan NP. Conjugated nitroxide radicals. RUSSIAN CHEMICAL REVIEWS 2022. [DOI: 10.1070/rcr5025] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Poggini L, Lunghi A, Collauto A, Barbon A, Armelao L, Magnani A, Caneschi A, Totti F, Sorace L, Mannini M. Chemisorption of nitronyl-nitroxide radicals on gold surface: an assessment of morphology, exchange interaction and decoherence time. NANOSCALE 2021; 13:7613-7621. [PMID: 33881100 DOI: 10.1039/d1nr00640a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A combined Tof-SIMS, XPS and STM characterization has been performed to study the deposition of a sulphur-functionalized nitronyl nitroxide radical on Au(111) clearly demonstrating the chemisorption of intact molecules. Continuous -wave EPR characterization showed that the radical molecules maintain their paramagnetic character. Pulsed EPR measurements allowed to determine the decoherence time of the nanostructure at 80 K, which turned out to be comparable to the one measured in frozen solution and longer than previously reported for many radicals and other paramagnetic molecules at much lower temperatures. Furthermore, we conducted a state-of-the-art ab initio molecular dynamics study, suggesting different possible scenarios for chemisorption geometries and predicting the energetically favoured geometry. Calculation of the magnetic properties indicates a partial non-innocent role of the gold surface in determining the magnetic interactions between radicals in packed structures. This suggests that the observed EPR spectrum is to be attributed to low-density domains of disordered radicals interacting via dipolar interactions.
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Affiliation(s)
- Lorenzo Poggini
- Department of Chemistry "Ugo Schiff" and INSTM Research Unit, University of Florence, I-50019 Sesto Fiorentino, Italy. and ICCOM-CNR, via Madonna del Piano 10, 50019 Sesto, Fiorentino, Italy.
| | - Alessandro Lunghi
- Department of Chemistry "Ugo Schiff" and INSTM Research Unit, University of Florence, I-50019 Sesto Fiorentino, Italy.
| | - Alberto Collauto
- Department of Chemical Sciences and INSTM Research Unit, University of Padua, I-35131 Padova, Italy
| | - Antonio Barbon
- Department of Chemical Sciences and INSTM Research Unit, University of Padua, I-35131 Padova, Italy
| | - Lidia Armelao
- Department of Chemical Sciences and INSTM Research Unit, University of Padua, I-35131 Padova, Italy and Institute of Condensed Matter Chemistry and Technologies for Energy, National Research Council of Italy, ICMATE-CNR, via Marzolo 1, 35131 Padua, Italy and Department of Chemical Sciences and Materials Technologies, National Research Council of Italy, DSCTM - CNR, Piazzale A. Moro 7, 00185 Rome, Italy
| | - Agnese Magnani
- Department of Biotechnologies, Chemistry and Pharmacy, and INSTM Research Unit, University of Siena, I-53100 Siena, Italy
| | - Andrea Caneschi
- DIEF - Department of Industrial Engineering and INSTM Research Unit, University of Florence, Via S. Marta 3, I-50139 Florence, Italy
| | - Federico Totti
- Department of Chemistry "Ugo Schiff" and INSTM Research Unit, University of Florence, I-50019 Sesto Fiorentino, Italy.
| | - Lorenzo Sorace
- Department of Chemistry "Ugo Schiff" and INSTM Research Unit, University of Florence, I-50019 Sesto Fiorentino, Italy.
| | - Matteo Mannini
- Department of Chemistry "Ugo Schiff" and INSTM Research Unit, University of Florence, I-50019 Sesto Fiorentino, Italy.
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Lecourt C, Izumi Y, Khrouz L, Toche F, Chiriac R, Bélanger-Desmarais N, Reber C, Fabelo O, Inoue K, Desroches C, Luneau D. Thermally-induced hysteretic valence tautomeric conversions in the solid state via two-step labile electron transfers in manganese-nitronyl nitroxide 2D-frameworks. Dalton Trans 2020; 49:15646-15662. [PMID: 33156311 DOI: 10.1039/d0dt03243c] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Near room temperature hysteretic thermo-induced valence tautomerism was discovered in a layered 2D-coordination polymer of manganese(ii) with nitronyl nitroxide radicals separated by ClO4- anions (1). This opens a novel approach towards switchable materials with hysteresis and under ambient conditions with prospects for applications and for investigating solid-state intramolecular electron transfers. Herein, two new compounds with similar layered structures where the anions (X) are BF4- (2) or PF6- (3) are presented. Their magnetic behaviors also reveal hysteretic thermo-induced valence tautomeric conversions but in two steps and evidencing a strong effect of the anion. This occurs near room temperature (278-220 K) for 2 and higher for 3 (380-330 K). Their single crystal structures at different temperatures show that this involves two successive thermally-triggered electron transfers with switching between three redox tautomers formulated as {[MnII2-yMnIIIy(NITIm)3-y(NITRed)y]X}n, where y is temperature dependent. Upon cooling from the high-temperature redox-tautomer (y = 0) to the intermediate one (y = 1), half of the manganese(ii) centers are oxidized to manganese(iii) and 1/3 of the nitronyl nitroxide radicals (NITIm-) are reduced to the aminoxyl form (NITRed2-). On further cooling, the second half of the manganese(ii) centers are oxidized and another 1/3 of the radicals are reduced to reach the low-temperature redox-tautomer (y = 2). Upon reheating, reverse electron transfers occur. This is complementarily supported by X-ray powder measurements, differential scanning calorimetry, and electron paramagnetic resonance and Raman spectroscopies. These multi-stable compounds in which manganese ions exchange reversibly their electron with the nitronyl nitroxide radical are outstanding rare examples of two-step valence tautomerism in the solid state promoted by the polymeric structure.
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Affiliation(s)
- Constance Lecourt
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Univ Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France.
| | - Yuuta Izumi
- Department of Chemistry, Graduate School of Science and Chirality Research Center (CResCent), Hiroshima University, 1-3-1, Kagamiyama, Higashi Hiroshima, Hiroshima, 739-8526, Japan
| | - Lhoussain Khrouz
- Univ Lyon, ENS de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, F69342, Lyon, France
| | - François Toche
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Univ Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France.
| | - Rodica Chiriac
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Univ Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France.
| | | | - Christian Reber
- Département de chimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Oscar Fabelo
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Katsuya Inoue
- Department of Chemistry, Graduate School of Science and Chirality Research Center (CResCent), Hiroshima University, 1-3-1, Kagamiyama, Higashi Hiroshima, Hiroshima, 739-8526, Japan
| | - Cédric Desroches
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Univ Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France.
| | - Dominique Luneau
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Univ Lyon, Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France.
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Assembly of Imidazolyl-Substituted Nitronyl Nitroxides into Ferromagnetically Coupled Chains. CRYSTALS 2019. [DOI: 10.3390/cryst9040219] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
New nitronyl nitroxides, namely, 2-(4,5-dimethylimidazol-2-yl)- and 2-(4,5-dichloroimidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl, were prepared in crystalline form. According to single-crystal X-ray data, intra- and intermolecular hydrogen bonds are formed between NH groups of the imidazole cycles and O atoms of the nitroxide moieties. The intermolecular H-bonds contribute to the alignment of molecules into chains along the a-axis; this alignment causes short intrachain contacts between O and C atoms carrying spin density of opposite signs. Such an arrangement of nitroxides induces ferromagnetic intrachain interactions (J ≈ 10 cm−1) between neighboring radicals.
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