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Ferrocenyl-substituted nitronyl nitroxide in the design of one-dimensional magnets. Dalton Trans 2024; 53:1714-1721. [PMID: 38167942 DOI: 10.1039/d3dt03858k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
By the reaction of M(hfac)2 (M = Mn(II), Co(II), Cu(II), and Zn(II); hfac is the hexafluoroacetylacetonate anion) and ferrocenyl-substituted nitronyl nitroxide (L), we succeeded in the synthesis of stable heterospin complexes: mononuclear [Zn(hfac)2L], trinuclear {[Cu(hfac)2]3L2} and chain polymer [Mn(hfac)2L]n and [Co(hfac)2L]n. The specific steric bulkiness of the ferrocenyl substituent leads to the formation of trans-type coordination polyhedra in the [Mn(hfac)2L]n and [Co(hfac)2L]n chains. The introduction of the ferrocene substituent leads to an effective weakening of intermolecular or interchain magnetic exchange coupling. Ferrimagnetic ordering was observed for one-dimensional complexes [M(hfac)2L]n (M = Mn(II), Co(II)). [Co(hfac)2L]n exhibits features of single-chain magnet behaviour: slow relaxation of magnetization below 13 K is associated with a high coercive field (54 kOe at 2 K).
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Magnetic Exchange Coupling through the Nonalternant Cyclopentadienyl π-System of Ferrocene. Org Lett 2021; 23:8235-8239. [PMID: 34586811 DOI: 10.1021/acs.orglett.1c02982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electronic and magnetic coupling through nonalternant π-systems is an area of intense interest in photonics and molecular electronics research, yet relatively little is known regarding coupling through nonalternant π-systems. Herein we present magnetic exchange coupling in two semiquinone-based biradicals: 1,3-SQ2Fc has two semiquinone radicals attached to the one- and three-positions of the same cyclopentadienyl ligand (a nonalternant π-system) of ferrocene, whereas 1,1'-SQ2Fc has one semiquinone radical attached to each of the two cyclopentadienyl ligands of ferrocene.
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Abstract
Electronic coupling through organic bridges facilitates magnetic exchange interactions and controls electron transfer and single-molecule device electron transport. Electronic coupling through alternant π-systems (e.g., benzene) is better understood than the corresponding coupling through nonalternant π-systems (e.g., azulene). Herein, we examine the structure, spectroscopy, and magnetic exchange coupling in two biradicals (1,3-SQ2Az and 1,3-SQ-Az-NN; SQ = the zinc(II) complex of spin-1/2 semiquinone radical anion, NN = spin-1/2 nitronylnitroxide; Az = azulene) that possess nonalternant azulene π-system bridges. The SQ radical spin density in both molecules is delocalized into the Az π-system, while the NN spin is effectively localized onto the five-atom ONCNO π-system of NN radical. The spin distributions and interactions are probed by EPR spectroscopy and magnetic susceptibility measurements. We find that J = +38 cm-1 for 1,3-SQ2Az and J = +9 cm-1 for 1,3-SQ-Az-NN (H=-2JS^SQ·S^SQorNN). Our results highlight the differences in exchange coupling mediated by azulene compared to exchange coupling mediated by alternant π-systems.
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Re( i)-nitroxide complexes. RSC Adv 2021; 11:19902-19907. [PMID: 35479223 PMCID: PMC9033687 DOI: 10.1039/d1ra02159a] [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: 03/18/2021] [Accepted: 05/25/2021] [Indexed: 11/21/2022] Open
Abstract
Stable nitroxide-substituted cyrhetrenes were synthesized and characterized by EPR, CV, XRD, magnetochemistry and quantum chemistry methods.
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Tris-pyridylmethylamine (TPMA) complexes functionalized with persistent nitronyl nitroxide organic radicals. Dalton Trans 2020; 49:10011-10016. [PMID: 32643714 DOI: 10.1039/d0dt01553a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The chance to have persistent organic radicals in combination with metals has attracted much interest since it offers the possibility of having new functional molecules with multiple open-shell elements. In this study, we report the synthesis of two tripodal tris(2-pyridyl)methylamine ligands (TPMA) functionalized with nitronyl nitroxide persistent radicals. The newly formed ligands have been used to coordinate zinc(ii), copper(ii), iron(ii) and cobalt(ii). The resulting complexes have been investigated by means of electron paramagnetic resonance (EPR), ESI-MS, FT-IR spectroscopy and X-ray diffraction. An electron reduction of the N-O radical moiety has been observed, depending on the metal used for the formation of the complex and the reaction conditions. We have observed small differences in the EPR spectra depending on the meta or para position of the radical moiety in the complex structure and some antiferromagnetic interactions between the paramagnetic M(ii) ions and the radical species.
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Revisiting the Ullman's Radical Chemistry for Phthalocyanine Derivatives. Chemistry 2018; 24:5359-5365. [DOI: 10.1002/chem.201704903] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Indexed: 11/07/2022]
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Ferrocene-based diradicals of imino nitroxide, nitronyl nitroxide and verdazyl, and their cations are possible SMM: A quantum chemical study. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.03.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Dynamics of intramolecular spin exchange interaction of a nitronyl nitroxide diradical in solution and on surfaces. NANOSCALE 2016; 8:5049-5058. [PMID: 26864080 DOI: 10.1039/c5nr08824k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this paper we report the study of the dynamics of a thermally modulated intramolecular spin exchange interaction of a novel diradical nitronyl nitroxide-substituted disulfide in solution and when it is grafted on a gold surface. The structure of this diradical was designed to have flexible chains leading to intramolecular collisions and hence spin exchange interaction, and with an appropriate binding group to be grafted on the gold surface to study its behavior on the surface. In solution, this diradical shows a strong spin exchange interaction between both radicals which is modulated by temperature, but also gold nanoparticles (AuNPs) functionalized with this diradical permit investigation of such a phenomenon in surface-grafted radicals. The spin-labelled AuNP synthesis was optimized to obtain high coverage of spin labels to lead to high spin exchange interaction. The obtained AuNPs were studied by Electron Paramagnetic Resonance (EPR), UV-Vis, and IR spectroscopies, HR-TEM microscopy, Cyclic Voltammetry (CV), Energy Dispersive X-ray analysis (EDX) and Thermogravimetric Analysis (TGA). This inorganic-organic hybrid material also showed dipolar interactions between its radicals which were confirmed by the appearance in the EPR spectra of an |Δms| = 2 transition at half-field. This signal gives direct evidence of the presence of a high-spin state and permitted us to study the nature of the magnetic coupling between the spins which was found to be antiferromagnetic. Self-Assembled Monolayers (SAMs) of these radicals on the Au (111) substrate were also prepared and studied by contact angle, X-Ray Photoelectron Spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Cyclic Voltammetry and EPR. The magnetic as well as the electrochemical properties of the hybrid surfaces were studied and compared with the properties of this diradical in solution. Analogies between the properties of AuNPs with high coverage of radicals and those of SAM were observed.
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Synthesis, Characterization, and Photophysical Studies of an Iron(III) Catecholate–Nitronylnitroxide Spin-Crossover Complex. Inorg Chem 2015; 54:4466-74. [DOI: 10.1021/acs.inorgchem.5b00298] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nano islet formation of formyl- and carboxyferrocene, -ruthenocene, -osmocene and cobaltocenium on amine-functionalized silicon wafers highlighted by crystallographic, AFM and XPS studies. J Organomet Chem 2013. [DOI: 10.1016/j.jorganchem.2013.08.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Three-Dimensional Porous Metal−Organic Frameworks Exhibiting Metamagnetic Behaviors: Synthesis, Structure, Adsorption, and Magnetic Properties. Inorg Chem 2010; 49:4301-6. [PMID: 20364849 DOI: 10.1021/ic100188w] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Novel ferrocenyl nitroxides: Synthesis, structures, electrochemistry and antioxidative activity. J Organomet Chem 2009. [DOI: 10.1016/j.jorganchem.2009.08.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Highly ylidic imidazoline-based fulvenes as suitable precursors for the synthesis of imidazolium-substituted metallocenes. Chemistry 2009; 14:10909-14. [PMID: 19003835 DOI: 10.1002/chem.200801956] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
The solid state structure of 1,1'-bis(verdazyl)ferrocene reveals the two radical moieties associated intramolecularly to give the first example of a pi-dimer of a stable verdazyl radical. The pi-dimer structure is not maintained in solution. Magnetic characterization indicates that the radicals are sufficiently strongly antiferromagnetically coupled so as to render the molecule diamagnetic at room temperature.
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Synthesis, X-ray structure and characterization of a novel [fc(IMH)2H]+[Co(hfac)3]− salt with hydrogen bonded ferrocenyl bis(imino hydroxylamino) building blocks. J Organomet Chem 2003. [DOI: 10.1016/s0022-328x(03)00502-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Synthesis, structure and reactivity study of 1,1′-bis(N-ter-butyl-N-hydroxyamino)ferrocene. J Organomet Chem 2002. [DOI: 10.1016/s0022-328x(02)01365-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ferrocene as a ferromagnetic coupler. Synthesis and characterization of a ferrocene bridged polychlorotriphenylmethyl diradical. J Organomet Chem 2001. [DOI: 10.1016/s0022-328x(01)00912-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Ferrocene substituted nitronyl nitroxide and imino nitroxide radicals. Synthesis, X-ray structure and magnetic properties. J Organomet Chem 2001. [DOI: 10.1016/s0022-328x(01)00954-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Synthesis, crystal structures and magnetic properties of transition metal–azide complexes coordinated with pyridyl nitronyl nitroxides. Inorganica Chim Acta 2001. [DOI: 10.1016/s0020-1693(01)00482-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Spin Frustration in a Dimeric Mn(II) Complex with a Metallocene-Substituted alpha-Nitronyl Nitroxide Radical This work was supported by grants from DGES (project PB96-0802-C02-01), CIRIT (project SGR 96-00106), Fonds zur Förderung der Wissenschaftlichen Forschung, Vienna (Project P 13128), Austrian Federal Ministry of Science (BMWV), Acción Integrada Hispano-Austríaca (HU-1999-0015), and the 3MD Network of the TMR program of the E.U. (contract ERBFMRX CT980181). C.S. thanks the Austrian Federal Ministry of Science for the award of a research scholarship. D.R.-M. thanks the Generalitat de Catalunya for a postdoctoral grant. The authors acknowledge the suggestions given by one of the referees. Angew Chem Int Ed Engl 2000; 39:3688-3691. [PMID: 11091441 DOI: 10.1002/1521-3773(20001016)39:20<3688::aid-anie3688>3.0.co;2-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Spinfrustration in einem dimeren MnII-Komplex mit Metallocen-substituiertenα-Nitronyl-Nitroxid-Radikalen. Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20001016)112:20<3842::aid-ange3842>3.0.co;2-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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