1
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Lussier DJ, Ito E, McClain KR, Smith PW, Kwon H, Rutkauskaite R, Harvey BG, Shuh DK, Long JR. Metal-Halide Covalency, Exchange Coupling, and Slow Magnetic Relaxation in Triangular (Cp iPr5) 3U 3X 6 (X = Cl, Br, I) Clusters. J Am Chem Soc 2024. [PMID: 39044394 DOI: 10.1021/jacs.3c11678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
The actinide elements are attractive alternatives to transition metals or lanthanides for the design of exchange-coupled multinuclear single-molecule magnets. However, the synthesis of such compounds is challenging, as is unraveling any contributions from exchange coupling to the overall magnetism. To date, only a few actinide compounds have been shown to exhibit exchange coupling and single-molecule magnetism. Here, we report triangular uranium(III) clusters of the type (CpiPr5)3U3X (1-X; X = Cl, Br, I; CpiPr5 = pentaisopropylcyclopentadienyl), which are synthesized via reaction of the aryloxide-bridged precursor (CpiPr5)2U2(OPhtBu)4 with excess Me3SiX. Spectroscopic analysis suggests the presence of covalency in the uranium-halide interactions arising from 5f orbital participation in bonding. The dc magnetic susceptibility data reveal the presence of antiferromagnetic exchange coupling between the uranium(III) centers in these compounds, with the strength of the exchange decreasing down the halide series. Ac magnetic susceptibility data further reveal all compounds to exhibit slow magnetic relaxation under zero dc field. In 1-I, which exhibits particularly weak exchange, magnetic relaxation occurs via a Raman mechanism associated with the individual uranium(III) centers. In contrast, for 1-Br and 1-Cl, magnetic relaxation occurs via an Orbach mechanism, likely involving relaxation between ground and excited exchange-coupled states. Significantly, in the case of 1-Cl, magnetic relaxation is sufficiently slow such that open magnetic hysteresis is observed up to 2.75 K, and the compound exhibits a 100-s blocking temperature of 2.4 K. This compound provides the first example of magnetic blocking in a compound containing only actinide-based ions, as well as the first example involving the uranium(III) oxidation state.
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Affiliation(s)
- Daniel J Lussier
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Emi Ito
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - K Randall McClain
- U.S. Navy, Naval Air Warfare Center, Weapons Division, Research Department, Chemistry Division, China Lake, California 93555, United States
| | - Patrick W Smith
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Hyunchul Kwon
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Ryte Rutkauskaite
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Benjamin G Harvey
- U.S. Navy, Naval Air Warfare Center, Weapons Division, Research Department, Chemistry Division, China Lake, California 93555, United States
| | - David K Shuh
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jeffrey R Long
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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2
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Zhu Z, Paul S, Zhao C, Wu J, Ying X, Ungur L, Wernsdorfer W, Meyer F, Tang J. Record Quantum Tunneling Time in an Air-Stable Exchange-Bias Dysprosium Macrocycle. J Am Chem Soc 2024; 146:18899-18904. [PMID: 38975975 DOI: 10.1021/jacs.4c07412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
In recent years, dysprosium macrocycle single-molecule magnets (SMMs) have received increasing attention due to their excellent air/thermal stability, strong magnetic anisotropy, and rigid molecular skeleton. However, they usually display fast zero-field quantum tunneling of the magnetization (QTM) rate, severely hindering their data storage applications. Herein, we report the design, synthesis, and characterization of an air-stable monodecker didysprosium macrocycle integrating strong single-ion anisotropy, near-perfect local crystal field (CF) symmetry, and efficient exchange bias. These indispensable features enable clear-cut elucidation of the crucial role of very weak antiferromagnetic coupling on magnetization dynamics, creating a prominent SMM with a large effective energy barrier (Ueff) of 670 cm-1, open hysteresis loops at zero field up to 14.9 K, and a record relaxation time of QTM (τQTM), 24281 s, for all known nonradical-bridged lanthanide SMMs.
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Affiliation(s)
- Zhenhua Zhu
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Sagar Paul
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Chen Zhao
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Jianfeng Wu
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China
| | - Xu Ying
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Liviu Ungur
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Wolfgang Wernsdorfer
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
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3
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Castellanos E, Benner F, Demir S. Linear, Electron-Rich Erbium Single-Molecule Magnet with Dibenzocyclooctatetraene Ligands. Inorg Chem 2024; 63:9888-9898. [PMID: 38738864 PMCID: PMC11134505 DOI: 10.1021/acs.inorgchem.4c00731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/11/2024] [Accepted: 04/23/2024] [Indexed: 05/14/2024]
Abstract
Judicious design of ligand scaffolds to highly anisotropic lanthanide ions led to substantial advances in molecular spintronics and single-molecule magnetism. Erbium-based single-molecule magnets (SMMs) are rare, which is attributed to the prolate-shaped ErIII ion requiring an equatorial ligand field for enhancing its single-ion magnetic anisotropy. Here, we present an electron-rich mononuclear Er SMM, [K(crypt-222)][Er(dbCOT)2], 1 (where dbCOT = dibenzocyclooctatetraene), that was obtained from a salt metathesis reaction of ErCl3 and K2dbCOT. The dipotassium salt, K2dbCOT, was generated through a two-electron reduction of the bare dbCOT0 ligand employing potassium graphite and was crystallized from DME to give the new solvated complex, [K(DME)]2[dbCOT]n, 2. 1 was analyzed through crystallography, electrochemistry, spectroscopy, magnetometry, and CASSCF calculations. The structure of 1 consists of an anionic metallocene complex featuring a linear (180.0°) geometry with an ErIII ion sandwiched between dianionic dbCOT ligands and an outer-sphere K+ ion encapsulated in 2.2.2-cryptand. Two pronounced redox events at negative potentials allude to the formation of a trianionic erbocene complex, [Er(dbCOT)2]3-, on the electrochemical time scale. 1 shows slow magnetic relaxation with an effective spin-reversal barrier of Ueff = 114(2) cm-1, which is close in magnitude to the calculated energies of the first and second excited states of 96.9 and 109.13 cm-1, respectively. 1 exhibits waist-constricted hysteresis loops below 4 K and constitutes the first example of an erbocene-SMM bearing fused aromatic rings to the central COT ligand. Notably, 1 comprises the largest COT scaffold implemented in erbocene SMMs, yielding the most electron-rich homoleptic erbium metallocene SMM.
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Affiliation(s)
- Ernesto Castellanos
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
| | - Florian Benner
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
| | - Selvan Demir
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
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4
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Delano F, Deshapriya S, Demir S. Guanidinate Yttrium Complexes Containing Bipyridyl and Bis(benzimidazolyl) Radicals. Inorg Chem 2024; 63:9659-9669. [PMID: 38569134 PMCID: PMC11134503 DOI: 10.1021/acs.inorgchem.4c00006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 02/26/2024] [Accepted: 03/06/2024] [Indexed: 04/05/2024]
Abstract
Ancillary ligand scaffolds that sufficiently stabilize a metal ion to allow its coordination to an open-shell ligand are scarce, yet their development is essential for next-generation spin-based materials with topical applications in quantum information science. To this end, a synthetic challenge must be met: devising molecules that enable the binding of a redox-active ligand through facile displacement and clean removal of a weakly coordinating anion. Here, we probe the accessibility of unprecedented radical-containing rare-earth guanidinate complexes by combining our recently discovered yttrium tetraphenylborate complex [{(Me3Si)2NC(NiPr)2}2Y][(μ-η6-Ph)(BPh3)] with the redox-active ligands 2,2'-bipyridine (bpy) and 2,2'-bis(benzimidazole) (Bbim), respectively, under reductive conditions. Our endeavor resulted in the first evidence of guanidinate complexes that contain radicals, namely, a mononuclear bipyridyl radical complex, {(Me3Si)2NC(NiPr)2}2Y(bpy•) (1), and a dinuclear bis(benzimidazolyl) radical-bridged complex, [K(crypt-222)][{(Me3Si)2NC(NiPr)2}2Y]2(μ-Bbim•) (2'). The latter was achieved by an in situ reduction of [{(Me3Si)2NC(NiPr)2}2Y]2(μ-Bbim) (2), which was isolated from a salt metathesis reaction. 1 and 2 were characterized by X-ray crystallography and IR and UV-vis spectroscopy. Variable-temperature electron paramagnetic resonance spectroscopy was applied to gain insight into the distribution of unpaired spin density on 1 and 2'. Density functional theory calculations were conducted on 1 and 2' to elucidate further their electronic structures. The redox activity of 1 and 2' was also probed by electrochemical methods.
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Affiliation(s)
| | | | - Selvan Demir
- Department of Chemistry, Michigan
State University (MSU), 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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5
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Manna F, Oggianu M, Galán-Mascarós JR, Pop F, Le Guennic B, Mercuri ML, Avarvari N. Tuning the slow magnetic relaxation with the substituents in anilate bridged bis(dysprosium) complexes. Dalton Trans 2024; 53:8369-8381. [PMID: 38669068 DOI: 10.1039/d4dt00175c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2024]
Abstract
Dinuclear lanthanide complexes [((HB(pz)3)2Dy)2(μ-Th2An)] (1Dy) and [((HB(pz)3)2Dy)2(μ-ClCNAn)] (2Dy), based on the hydrotris(pyrazol-1-yl)borate (HBpz3-) scorpionate capping ligand and anilate (An2-) bridging linkers, namely homosubstituted dithiophene- and heterosubstituted chlorocyanoanilate, bearing electron-donating and withdrawing substituents at the 3,6-positions of the benzoquinone core, are reported. 1Dy shows an octacoordinated {N6O2} DyIII ion within a D4h distorted square antiprismatic coordination, an ideal geometry for Single-Molecule Magnet (SMM) behavior, given its oblate nature, whereas in 2Dy the octacoordinated DyIII ion adopts a D2d triangular dodecahedron geometry, while maintaining the same {N6O2} coordination sphere. Both complexes show field-induced single molecule magnet (SMM) behaviour, with tuning of the slow magnetic relaxation as a function of the nature of the substituents at the 3,6-positions of the anilate moiety. A comparison of the Arrhenius fitting parameters for 1Dy and 2Dy supports the hypothesis that square antiprismatic DyIII complexes, as 1Dy, exhibit higher energy barriers. This interpretation is supported by ab initio calculations that also shed light on the crucial role of intermolecular dipolar interactions.
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Affiliation(s)
- Fabio Manna
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
- Univ Angers, CNRS, MOLTECH-ANJOU, SFR MATRIX, F-49000 Angers, France.
- INSTM, Via Giuseppe Giusti, 9, 50121 Firenze, Italy
| | - Mariangela Oggianu
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
- INSTM, Via Giuseppe Giusti, 9, 50121 Firenze, Italy
| | - José Ramón Galán-Mascarós
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Av. Països Catalans 16, E-43007 Tarragona, Spain
- ICREA, Passeig Lluis Companys, 23, Barcelona 08010, Spain
| | - Flavia Pop
- Univ Angers, CNRS, MOLTECH-ANJOU, SFR MATRIX, F-49000 Angers, France.
| | - Boris Le Guennic
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France
| | - Maria Laura Mercuri
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
- INSTM, Via Giuseppe Giusti, 9, 50121 Firenze, Italy
| | - Narcis Avarvari
- Univ Angers, CNRS, MOLTECH-ANJOU, SFR MATRIX, F-49000 Angers, France.
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6
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Biswas B, Siddiqui AI, Majee MC, Saha SK, Mondal B, Saha R, Gómez García CJ. Heptanuclear Mixed-Valence Co 4IIICo 3II Molecular Wheel─A Molecular Analogue of Layered Double Hydroxides with Single-Molecule Magnet Behavior and Electrocatalytic Activity for Hydrogen Evolution Reactions. Inorg Chem 2024; 63:6161-6172. [PMID: 38526851 PMCID: PMC11005049 DOI: 10.1021/acs.inorgchem.3c04065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/26/2024] [Accepted: 02/26/2024] [Indexed: 03/27/2024]
Abstract
We present a bifunctional heptanuclear cobalt(II)/cobalt(III) molecular complex formulated as [Co7(μ3-OH)4(H2L1)2(HL2)2](NO3)6·6H2O (1) (where H5L1 is 2,2'-(((1E,1'E)-((2-hydroxy-5-methyl-1,3-phenylene)bis(methanylylidene))bis(azanylylidene))bis(propane-1,3-diol)) and H2L2 is 2-amino-1,3-propanediol). Compound 1 has been characterized by single-crystal X-ray diffraction analysis along with other spectral and magnetic measurements. Structural analysis indicates that 1 contains a mixed-valence Co7 cluster where a central Co(II) ion is connected to six different Co centers (four CoIII and two CoII ions) by four μ3-OH groups, giving rise to a planar heptanuclear cluster that resembles a molecular fragment of a layered double hydroxide (LDH). Two triply deprotonated (H2L1)3- ligands form the outer side of the cluster while two singly deprotonated (HL2)- ligands are located at the top and bottom of the central heptanuclear core. Variable temperature magnetic measurements indicate the presence of weak ferromagnetic CoII···CoII interactions (J = 3.53(6) cm-1) within the linear trinuclear CoII cluster. AC susceptibility measurements show that 1 is a field-induced single-molecule magnet (SMM) with τ0 = 8.2(7) × 10-7 s and Ueff = 11.3(4) K. The electrocatalytic hydrogen evolution reaction (HER) activity of 1 in homogeneous phase shows an overpotential of 455 mV, with a Faradaic efficiency of 81% and a TOF of 8.97 × 104 μmol H2 h-1 mol-1.
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Affiliation(s)
- Biplab Biswas
- Department
of Chemistry, Kazi Nazrul University, Asansol 713340, West Bengal, India
- Department
of Chemistry, Hooghly Mohsin College, Chinsurah 712101, West Bengal, India
| | | | | | - Swadhin Kumar Saha
- Department
of Chemistry, Kazi Nazrul University, Asansol 713340, West Bengal, India
| | - Biswajit Mondal
- Department
of Chemistry, IIT Gandhinagar, Palaj 382355, Gujarat, India
| | - Rajat Saha
- Department
of Chemistry, Kazi Nazrul University, Asansol 713340, West Bengal, India
- Departamento
de Química Inorgánica, Universidad
de Valencia, Burjasot, Valencia 46100, Spain
| | - Carlos J. Gómez García
- Departamento
de Química Inorgánica, Universidad
de Valencia, Burjasot, Valencia 46100, Spain
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7
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Suhr S, Hunger D, Walter RRM, Köhn A, van Slageren J, Sarkar B. Air-Stable Dinuclear Complexes of Four-Coordinate Zn II and Ni II Ions with a Radical Bridge: A Detailed Look at Redox Activity and Antiferromagnetic Coupling. Inorg Chem 2024; 63:6042-6050. [PMID: 38502792 DOI: 10.1021/acs.inorgchem.4c00351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Air-stable dinuclear complexes [(bmsab)NiII(tmsab)NiII(bmsab)]3- and [(bmsab)ZnII(tmsab)ZnII(bmsab)]3- (bmsab = bis(methanesulfoneamido)benzene, tmsab = tetra(methanesulfonamido)benzene) were prepared via a synthetic route based on heteroleptic precursor complexes. The new complexes combine a distorted tetrahedral coordination environment with an open-shell bridging ligand. The ZnII species was subjected to a detailed investigation of the (spectro-)electrochemical processes. The NiII species is a rare example of a complex that combines strong exchange coupling (J > 440 cm-1) with pronounced positive zero-field splitting (D = +72 cm-1). Combining SQUID magnetometry and (HF)EPR spectroscopy with ab initio calculations allowed for accurate quantification of the exchange interaction.
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Affiliation(s)
- Simon Suhr
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - David Hunger
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Robert R M Walter
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Andreas Köhn
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Joris van Slageren
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Biprajit Sarkar
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
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8
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Dunstan MA, Giansiracusa MJ, Calvello S, Sorace L, Krause-Heuer AM, Soncini A, Mole RA, Boskovic C. Ab initio-based determination of lanthanoid-radical exchange as visualised by inelastic neutron scattering. Chem Sci 2024; 15:4466-4477. [PMID: 38516080 PMCID: PMC10952085 DOI: 10.1039/d3sc04229d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 02/12/2024] [Indexed: 03/23/2024] Open
Abstract
Magnetic exchange coupling can modulate the slow magnetic relaxation in single-molecule magnets. Despite this, elucidation of exchange coupling remains a significant challenge for the lanthanoid(iii) ions, both experimentally and computationally. In this work, the crystal field splitting and 4f-π exchange coupling in the erbium-semiquinonate complex [ErTp2dbsq] (Er-dbsq; Tp- = hydro-tris(1-pyrazolyl)borate, dbsqH2 = 3,5-di-tert-butyl-1,2-semiquinone) have been determined by inelastic neutron scattering (INS), magnetometry, and CASSCF-SO ab initio calculations. A related complex with a diamagnetic ligand, [ErTp2trop] (Er-trop; tropH = tropolone), has been used as a model for the crystal field splitting in the absence of coupling. Magnetic and INS data indicate antiferromagnetic exchange for Er-dbsq with a coupling constant of Jex = -0.23 meV (-1.8 cm-1) (-2Jex formalism) and good agreement is found between theory and experiment, with the low energy magnetic and spectroscopic properties well modelled. Most notable is the ability of the ab initio modelling to reproduce the signature of interference between localised 4f states and delocalised π-radical states that is evident in the Q-dependence of the exchange excitation. This work highlights the power of combining INS with EPR and magnetometry for determination of ground state properties, as well as the enhanced capability of CASSCF-SO ab initio calculations and purposely developed ab initio-based theoretical models. We deliver an unprecedentedly detailed representation of the entangled character of 4f-π exchange states, which is obtained via an accurate image of the spin-orbital transition density between the 4f-π exchange coupled wavefunctions.
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Affiliation(s)
- Maja A Dunstan
- School of Chemistry, The University of Melbourne Parkville VIC 3010 Australia
| | | | - Simone Calvello
- School of Chemistry, The University of Melbourne Parkville VIC 3010 Australia
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001 Kirrawee DC 2232 Australia
| | - Lorenzo Sorace
- INFN Sez. di Firenze, Department of Chemistry, "Ugo Schiff", Università Degli Studi Firenze Via Della Lastruccia, 13 50019 Sesto Fiorentino Italy
| | - Anwen M Krause-Heuer
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001 Kirrawee DC 2232 Australia
| | - Alessandro Soncini
- School of Chemistry, The University of Melbourne Parkville VIC 3010 Australia
- Department of Chemical Sciences, University of Padova Via Marzolo 1 35131 Padova Italy
| | - Richard A Mole
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001 Kirrawee DC 2232 Australia
| | - Colette Boskovic
- School of Chemistry, The University of Melbourne Parkville VIC 3010 Australia
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9
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David G, Duplaix-Rata G, Le Guennic B. What governs magnetic exchange couplings in radical-bridged dinuclear complexes? Phys Chem Chem Phys 2024; 26:8952-8964. [PMID: 38436408 DOI: 10.1039/d3cp06243k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Coupling transition metal or lanthanide ions through a radical bridging ligand is a promising route to increase performances in the area of single molecular magnets. A better understanding of the underlying physical mechanisms governing the magnetic exchange couplings is thus of valuable importance to design future compounds. Here, couplings in three series of metal-radical-metal compounds based on transition metal ions are investigated by means of the decomposition/recomposition methods. This work presents the generalisation and first application of the method to systems with an arbitrary number of magnetic centres featuring several unpaired electrons. Thanks to the decomposition into the three main contributions (direct exchange, kinetic exchange, and spin polarisation) as well as a description in terms of electron-electron interactions, we study the influence of the nature of the metal centre and the radical ligand on the couplings. We combine the energetic contributions extracted with orbital and charge population analysis to rationalise the results.
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Affiliation(s)
- Grégoire David
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France.
| | - Gwenhaël Duplaix-Rata
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France.
| | - Boris Le Guennic
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France.
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10
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Lehtonen A. Metal Complexes of Redox Non-Innocent Ligand N, N'-Bis(3,5-di- tertbutyl-2-hydroxy-phenyl)-1,2-phenylenediamine. Molecules 2024; 29:1088. [PMID: 38474599 DOI: 10.3390/molecules29051088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
Redox non-innocent ligands react with metal precursors to form complexes where the oxidation states of the ligand and thus the metal atom cannot be easily defined. A well-known example of such ligands is bis(o-aminophenol) N,N'-bis(3,5-di-tertbutyl-2-hydroxy-phenyl)-1,2-phenylenediamine, previously developed by the Wieghardt group, which has a potentially tetradentate coordination mode and four distinct protonation states, whereas its electrochemical behavior allows for five distinct oxidation states. This rich redox chemistry, as well as the ability to coordinate to various transition metals, has been utilized in the syntheses of metal complexes with M2L, ML and ML2 stoichiometries, sometimes supported with other ligands. Different oxidation states of the ligand can adopt different coordination modes. For example, in the fully oxidized form, two N donors are sp2-hybridized, which makes the ligand planar, whereas in the fully reduced form, the sp3-hybridized N donors allow the formation of more flexible chelate structures. In general, the metal can be reduced during complexation, but redox processes of the isolated complexes typically occur on the ligand. Combination of this non-innocent ligand with redox-active transition metals may lead to complexes with interesting magnetic, electrochemical, photonic and catalytic properties.
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Affiliation(s)
- Ari Lehtonen
- Intelligent Materials Chemistry Research Group, Department of Chemistry, University of Turku, FI-20014 Turku, Finland
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11
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Vieru V, Gómez-Coca S, Ruiz E, Chibotaru LF. Increasing the Magnetic Blocking Temperature of Single-Molecule Magnets. Angew Chem Int Ed Engl 2024; 63:e202303146. [PMID: 37539652 DOI: 10.1002/anie.202303146] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/18/2023] [Accepted: 08/02/2023] [Indexed: 08/05/2023]
Abstract
The synthesis of single-molecule magnets (SMMs), magnetic complexes capable of retaining magnetization blocking for a long time at elevated temperatures, has been a major concern for magnetochemists over the last three decades. In this review, we describe basic SMMs and the different approaches that allow high magnetization-blocking temperatures to be reached. We focus on the basic factors affecting magnetization blocking, magnetic axiality and the height of the blocking barrier, which can be used to group different families of complexes in terms of their SMM efficiency. Finally, we discuss several practical routes for the design of mono- and polynuclear complexes that could be applied in memory devices.
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Affiliation(s)
- Veacheslav Vieru
- Maastricht Science Programme, Faculty of Science and Engineering, Maastricht University, 6229 EN, Maastricht, The Netherlands
| | - Silvia Gómez-Coca
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, 08028, Barcelona, Spain
- Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, 08028, Barcelona, Spain
| | - Eliseo Ruiz
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, 08028, Barcelona, Spain
- Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, 08028, Barcelona, Spain
| | - Liviu F Chibotaru
- Theory of Nanomaterials Group, Katholieke Universiteit Leuven, 3001, Leuven, Belgium
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12
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Michael S, Jeyaraman P, Marimuthu B, Rajamanikam R, Thanasamy R, Arunsunai Kumar K, Mitu L, Raman N. Pharmaceutical manifestation of Knoevenagel condensed metal (II) complexes through virtual, in vitro and in vivo assessments. J Biomol Struct Dyn 2024:1-15. [PMID: 38189286 DOI: 10.1080/07391102.2023.2301059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 12/26/2023] [Indexed: 01/09/2024]
Abstract
Sulphur containing compounds possess a great deal of interest due to wide range of beneficial activities towards biotic species. This work also deals with the study of biological examination of newly synthesized sulphur containing Cu(II) and Zn(II) complexes derived from (E)-4-(phenylimino)-3-((E)-1-(phenylimino)ethyl)pent-2-ene-1-thiol Schiff bases. Moreover, the DNA nuclease efficiency of the synthesized metal complexes is studied by UV absorption studies, Fluorescence studies, Viscosity and CV titrations which confirm the intercalative mode of binding. Pharmacokinetic studies and drug like activity of these compounds are screened with the help of SWISS ADME online freeware. Their morphological nature is corroborated by various spectral techniques. Optimized geometry and biologically accessible nature of the synthesized compounds are investigated by Gaussian 09 W software. Interestingly, molecular docking studies are carried out against cancer DNA and 6J10 cancer cell. Anti-inflammatory and in vitro antioxidant activities have been studied to validate the theoretical prediction. Based on these preliminary pharmacological activities, the in vitro cytotoxicity and in vivo antitumor activities are examined using MCF-7, HeLa, Hep-2, HepG-2 and Ehrlich ascites carcinoma (EAC) cell lines. All the above examinations reveal that the nitro substituted transition metal complexes possess higher biological bustle.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Samuel Michael
- Research Department of Chemistry, VHNSN College, Virudhungar, India
- Department of Chemistry, PSR Engineering College, Sivakasi, India
| | - Porkodi Jeyaraman
- Post Graduate and Research Department of Chemistry, The Standard Fireworks Rajaratnam College for Women (Autonomous), Sivakasi, India
| | | | | | - Radha Thanasamy
- Department of Chemistry, Saiva Bhanu Kshatriya College, Aruppukottai, India
| | | | - Liviu Mitu
- Department of Chemistry, University of Pitesti, Pitesti, Romania
| | - Natarajan Raman
- Research Department of Chemistry, VHNSN College, Virudhungar, India
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13
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Haga N, Ishida T. A Triplet/Singlet Ground-State Switch via the Steric Inhibition of Conjugation in 4,6-Bis(trifluoromethyl)-1,3-phenylene Bisnitroxide. Molecules 2023; 29:70. [PMID: 38202653 PMCID: PMC10779647 DOI: 10.3390/molecules29010070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/12/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
Ground triplet 4,6-bis(trifluoromethyl)-1,3-phenylene bis(tert-butyl nitroxide) (TF2PBN) reacted with [Y(hfac)3(H2O)2] (hfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dionate), affording a doubly hydrogen-bonded adduct [Y(hfac)3(H2O)2(TF2PBN)]. The biradical was recovered from the adduct through recrystallization. Crystallographic analysis indicates that the torsion angles (|θ| ≤ 90°) between the benzene ring and nitroxide groups were 74.9 and 84.8° in the adduct, which are larger than those of the starting material TF2PBN. Steric congestion due to o-trifluoromethyl groups gives rise to the reduction of π-conjugation. Two hydrogen bonds enhance this deformation. Susceptometry of the adduct indicates a ground singlet with 2J/kB = -128(2) K, where 2J corresponds to the singlet-triplet gap. The observed magneto-structure relation is qualitatively consistent with Rajca's pioneering work. A density functional theory calculation at the UB3LYP/6-311+G(2d,p) level using the atomic coordinates determined provided a result of 2J/kB = -162.3 K for the adduct, whilst the corresponding calculation on intact TF2PBN provided +87.2 K. After a comparison among a few known compounds, the 2J vs. |θ| plot shows a negative slope with a critical torsion of 65(3)°. The ferro- and antiferromagnetic coupling contributions are balanced in TF2PBN, being responsible for ground-state interconversion by means of small structural perturbation like hydrogen bonds.
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Affiliation(s)
| | - Takayuki Ishida
- Department of Engineering Science, The University of Electro-Communications, Chofu 182-8585, Tokyo Prefecture, Japan
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14
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Lien CY, Boyn JN, Anferov SW, Mazziotti DA, Anderson JS. Origin of Weak Magnetic Coupling in a Dimanganese(II) Complex Bridged by the Tetrathiafulvalene-Tetrathiolate Radical. Inorg Chem 2023; 62:19488-19497. [PMID: 37967380 DOI: 10.1021/acs.inorgchem.3c02534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Magnetic exchange coupling (J) between different spin centers plays a crucial role in molecule-based magnetic materials. Direct exchange coupling between an organic radical and a metal is frequently stronger than superexchange through diamagnetic ligands, and the strategy of using organic radicals to engender desirable magnetic properties has been an area of active investigation. Despite significant advances and exciting bulk properties, the magnitude of J for radical linkers bridging paramagnetic centers is still difficult to rationally predict. It is thus important to elucidate the features of organic radicals that govern this parameter. Here, we measure J for the tetrathiafulvalene-tetrathiolate radical (TTFtt3-•) in a dinuclear Mn(II) complex. Magnetometry studies show that the antiferromagnetic coupling in this complex is much weaker than that in related Mn(II)-radical compounds, in contrast to what might be expected for the S-based chelating donor atoms of TTFtt. Experimental and computational analyses suggest that this small J coupling may be attributed to poor overlap between Mn- and TTFtt-based magnetic orbitals coupled with insignificant spin density on the coordinating S-atoms. These factors override any expected increase in J from the comparatively strong S-donors. This work elucidates the magnetic coupling properties of the TTFtt3-• radical for the first time and also demonstrates how multiple competing factors must be considered in rationally designing organic radical ligands for molecular-based magnetic compounds.
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Affiliation(s)
- Chen-Yu Lien
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Jan-Niklas Boyn
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Sophie W Anferov
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - David A Mazziotti
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - John S Anderson
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
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15
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Shah SJ, Pandit YA, Garribba E, Ishida M, Rath SP. Stable Dication Diradicals of Triply Fused Metallo Chlorin-Porphyrin Heterodimers: Impact of the Bridge on the Control of Spin Coupling to Reactivity. Chemistry 2023; 29:e202301963. [PMID: 37602834 DOI: 10.1002/chem.202301963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/16/2023] [Accepted: 08/16/2023] [Indexed: 08/22/2023]
Abstract
We report an unexpected rearrangement, controlled by the nature of the bridge, leading to the formation of novel, remarkably stable triply fused dinickel(II)/dicopper(II) chlorin-porphyrin dication diradical heterodimers in excellent yields. Here, a dipyrromethene bridge gets completely fused between two porphyrin macrocycles with two new C-C and one C-N bonds. The two macrocycles exhibit extensive π-conjugation through the bridge, which results in an antiferromagnetic coupling between the two π-cation radicals. In addition, the macrocyclic distortion also favours a rare intramolecular ferromagnetic interaction between the CuII and π-cation radical spins to form a triplet state. The structural and electronic perturbation in the unconjugated dication diradical possibly enables the bridging pyrrolic nitrogen to undergo a nucleophilic attack at the nearby β-carbon of the porphyrin π-cation radical with a computed free energy barrier of >20 kcal mol-1 which was supplied in the form of reflux condition to initiate such a rearrangement process. UV-vis, EPR and ESI-MS spectroscopies were used to monitor the rearrangement process in situ in order to identify the key reactive intermediates leading to such an unusual transformation.
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Affiliation(s)
- Syed Jehanger Shah
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Younis Ahmad Pandit
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Eugenio Garribba
- Dipartimento di Medicina, Chirurgia e Farmacia, Università di Sassari, Viale San Pietro, 07100, Sassari, Italy
| | - Masatoshi Ishida
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Tokyo, 192-0397, Japan
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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16
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Arumugam S, Schwarz B, Ravichandran P, Kumar S, Ungur L, Mondal KC. Dipotassiumtetrachloride-bridged dysprosium metallocenes: a single-molecule magnet. Dalton Trans 2023; 52:15326-15333. [PMID: 37387215 DOI: 10.1039/d3dt01325a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
The present work describes the dynamic magnetic properties of the complex [(CpAr3)4DyIII2Cl4K2]·3.5(C7H8) (1), synthesized by employing a tri-aryl-substituted cyclopentadienyl ligand (CpAr3), [4,4'-(4-phenylcyclopenta-1,3-diene-1,2-diyl)bis(methylbenzene) = CpAr3H]. Each Dy(III)-metallocene weakly couples via K2Cl4, displaying slow relaxation of magnetization below 14.5 K under zero applied dc field via KD3 energy levels with an energy barrier of 136.9/133.7 cm-1 on the Dy sites. The single-ion axial anisotropy energy barrier is reduced by geometrical distortion due to the coordination of two chloride ions at each Dy centre.
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Affiliation(s)
- Selvakumar Arumugam
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, India.
| | - Björn Schwarz
- Institute for Applied Materials - Energy Storage Systems (IAM-ESS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
| | | | - Sunil Kumar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, India.
| | - Liviu Ungur
- Department of Chemistry, National University of Singapore, Singapore.
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17
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Shu C, Yang Z, Rajca A. From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals. Chem Rev 2023; 123:11954-12003. [PMID: 37831948 DOI: 10.1021/acs.chemrev.3c00406] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
Stable radicals and thermally robust high-spin di- and triradicals have emerged as important organic materials due to their promising applications in diverse fields. New fundamental properties, such as SOMO/HOMO inversion of orbital energies, are explored for the design of new stable radicals, including highly luminescent ones with good photostability. A relation with the singlet-triplet energy gap in the corresponding diradicals is proposed. Thermally robust high-spin di- and triradicals, with energy gaps that are comparable to or greater than a thermal energy at room temperature, are more challenging to synthesize but more rewarding. We summarize a number of high-spin di- and triradicals, based on nitronyl nitroxides that provide a relation between the experimental pairwise exchange coupling constant J/k in the high-spin species vs experimental hyperfine coupling constants in the corresponding monoradicals. This relation allows us to identify outliers, which may correspond to radicals where J/k is not measured with sufficient accuracy. Double helical high-spin diradicals, in which spin density is delocalized over the chiral π-system, have been barely explored, with the sole example of such high-spin diradical possessing alternant π-system with Kekulé resonance form. Finally, we discuss a high-spin diradical with electrical conductivity and derivatives of triangulene diradicals.
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Affiliation(s)
- Chan Shu
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Zhimin Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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18
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Armenis AS, Alexandropoulos DI, Worrell A, Cunha-Silva L, Dunbar KR, Stamatatos TC. Peripheral site modification in a family of dinuclear [Dy 2(hynad) 2-6(NO 3) 0-6(sol) 0-2] 0/2- single-molecule magnets bearing a {Dy 2(μ-OR) 2} 4+ diamond-shaped core and exhibiting dissimilar magnetic dynamics. Dalton Trans 2023; 52:13565-13577. [PMID: 37724338 DOI: 10.1039/d3dt02596a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
The first use of the organic chelate N-hydroxy-1,8-naphthalimide (hynadH) in DyIII chemistry has unveiled access to a synthetic 'playground' composed of four new dinuclear complexes, all of which possess the same planar {Dy2(μ-OR)2}4+ diamond-shaped core, resulting from the bridging and chelating capacity of the hynad- groups. The structural stability of the central {Dy2} core has allowed for the modulation of the peripheral coordination sites of the metal ions, and specifically the NO3-/hynad- ratio of capping groups, thus affording the compounds [Dy2(hynad)2(NO3)4(DMF)2] (1), (Me4N)2[Dy2(hynad)2(NO3)6] (2), [Dy2(hynad)4(NO3)2(H2O)2] (3), and [Dy2(hynad)6(H2O)2] (4). Because of the chemical and structural modifications in the series 1-4, the DyIII coordination polyhedra are also dissimilar, comprising the muffin (1 and 3), tetradecahedral (2), and spherical tricapped trigonal prismatic (4) geometries. Complexes 1, 2, and 4 exhibit a ferromagnetic response at low temperatures, while 3 is antiferromagnetically coupled. All compounds exhibit out-of-phase (χ''M) ac signals as a function of ac frequency and temperature, thus behaving as single-molecule magnets (SMMs), in the absence or presence of applied dc fields. Interestingly, the hynad--rich and nitrato-free complex 4, demonstrates the largest energy barrier (Ueff = 69.62(1) K) for the magnetization reversal which is attributed to the presence of the two axial triangular faces of the spherical tricapped trigonal prism by the negatively charged O-atoms of the hynad- ligands.
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Affiliation(s)
| | | | - Anne Worrell
- Department of Chemistry, 1812 Sir Isaac Brock Way, Brock University, L2S 3A1 St Catharines, Ontario, Canada.
| | - Luís Cunha-Silva
- LAQV/REQUIMTE & Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal.
| | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
| | - Theocharis C Stamatatos
- Department of Chemistry, University of Patras, 26504 Patras, Greece.
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE - HT), Platani, P.O. Box 1414, 26504, Patras, Greece
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19
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Mondal A, Price CG, Tang J, Layfield RA. Targeted Synthesis of End-On Dinitrogen-Bridged Lanthanide Metallocenes and Their Reactivity as Divalent Synthons. J Am Chem Soc 2023; 145:20121-20131. [PMID: 37656516 PMCID: PMC10510326 DOI: 10.1021/jacs.3c07600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Indexed: 09/03/2023]
Abstract
High-yield syntheses of the lanthanide dinitrogen complexes [(Cp2tttM)2(μ-1,2-N2)] (1M, M = Gd, Tb, Dy; Cpttt = 1,2,4-C5tBu3H2), in which the [N2]2- ligands solely adopt the rare end-on or 1,2-bridging mode, are reported. The bulk of the tert-butyl substituents and the smaller radii of gadolinium, terbium, and dysprosium preclude formation of the side-on dinitrogen bonding mode on steric grounds. Elongation of the nitrogen-nitrogen bond relative to N2 is observed in 1M, and their Raman spectra show a major absorption consistent with N═N double bonds. Computational analysis of 1Gd identifies that the local symmetry of the metallocene units lifts the degeneracy of two 5dπ orbitals, leading to differing overlap with the π* orbitals of [N2]2-, a consequence of which is that the dinitrogen ligand occupies a singlet ground state. Magnetic measurements reveal antiferromagnetic exchange in 1M and single-molecule magnet (SMM) behavior in 1Dy. Ab initio calculations show that the magnetic easy axis in the ground doublets of 1Tb and 1Dy align with the {M-N═N-M} connectivity, in contrast to the usual scenario in dysprosium metallocene SMMs, where the axis passes through the cyclopentadienyl ligands. The [N2]2- ligands in 1M allow these compounds to be regarded as two-electron reducing agents, serving as synthons for divalent gadolinium, terbium, and dysprosium. Proof of principle for this concept is obtained in the reactions of 1M with 2,2'-bipyridyl (bipy) to give [Cp2tttM(κ2-bipy)] (2M, M = Gd, Tb, Dy), in which the lanthanide is ligated by a bipy radical anion, with strong metal-ligand direct exchange coupling.
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Affiliation(s)
- Arpan Mondal
- Department
of Chemistry, School of Life Sciences, University
of Sussex, Brighton BN1 9QJ, U.K.
| | - Christopher G.
T. Price
- Department
of Chemistry, School of Life Sciences, University
of Sussex, Brighton BN1 9QJ, U.K.
| | - Jinkui Tang
- State
Key Laboratory of Rare Earth Resource Utilization, Changchun Institute
of Applied Chemistry, Chinese Academy of
Sciences, Changchun 130022, P.R. China
| | - Richard A. Layfield
- Department
of Chemistry, School of Life Sciences, University
of Sussex, Brighton BN1 9QJ, U.K.
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20
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Abstract
Heteroatom-centered diradical(oid)s have been in the focus of molecular main group chemistry for nearly 30 years. During this time, the diradical concept has evolved and the focus has shifted to the rational design of diradical(oid)s for specific applications. This review article begins with some important theoretical considerations of the diradical and tetraradical concept. Based on these theoretical considerations, the design of diradical(oid)s in terms of ligand choice, steric, symmetry, electronic situation, element choice, and reactivity is highlighted with examples. In particular, heteroatom-centered diradical reactions are discussed and compared with closed-shell reactions such as pericyclic additions. The comparison between closed-shell reactivity, which proceeds in a concerted manner, and open-shell reactivity, which proceeds in a stepwise fashion, along with considerations of diradical(oid) design, provides a rational understanding of this interesting and unusual class of compounds. The application of diradical(oid)s, for example in small molecule activation or as molecular switches, is also highlighted. The final part of this review begins with application-related details of the spectroscopy of diradical(oid)s, followed by an update of the heteroatom-centered diradical(oid)s and tetraradical(oid)s published in the last 10 years since 2013.
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Affiliation(s)
- Alexander Hinz
- Institut für Anorganische Chemie (AOC), Karlsruher Institut für Technologie (KIT), Engesserstrasse 15, 76131 Karlsruhe, Germany
| | - Jonas Bresien
- Institut für Chemie, Universität Rostock, Albert-Einstein-Strasse 3a, 18059 Rostock, Germany
| | - Frank Breher
- Institut für Anorganische Chemie (AOC), Karlsruher Institut für Technologie (KIT), Engesserstrasse 15, 76131 Karlsruhe, Germany
| | - Axel Schulz
- Institut für Chemie, Universität Rostock, Albert-Einstein-Strasse 3a, 18059 Rostock, Germany
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21
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Wakizaka M, Ishikawa R, Tanaka H, Gupta S, Takaishi S, Yamashita M. Creation of a Field-Induced Co(II) Single-Ion Magnet by Doping into a Zn(II) Diamagnetic Metal-Organic Framework. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2301966. [PMID: 37178437 DOI: 10.1002/smll.202301966] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 05/01/2023] [Indexed: 05/15/2023]
Abstract
The combination of single-ion magnets (SIMs) and metal-organic frameworks (MOFs) is expected to produce new quantum materials. The principal issue to be solved in this regard is the development of new strategies for the synthesis of SIM-MOFs. This work demonstrates a new simple strategy for the synthesis of SIM-MOFs where a diamagnetic MOF is used as the framework into which the SIM sites are doped. 1, 0.5, and 0.2 mol% of the Co(II) ions are doped into the Zn(II) sites of [CH6 N3 ][ZnII (HCOO)3 ]. The doped Co(II) sites in the MOFs perform as SIM with a positive D term of zero-field splitting. The longest magnetic relaxation time is 150 ms (0.2 mol% Co) at 1.8 K under a static field of 0.1 T. Temperature dependency of the relaxation time suggests suppressing magnetic relaxation by reduction of spin-spin interaction upon doping in the rigid framework. Thus, this work represents a proof of concept for the creation of a single-ion doped magnet in the MOF. This simple synthetic strategy will be widely applied for the creation of quantum magnetic materials.
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Affiliation(s)
- Masanori Wakizaka
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Ryuta Ishikawa
- Department of Chemistry, Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-Ku, Fukuoka, 814-0180, Japan
| | - Hisaaki Tanaka
- Department of Applied Physics, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya, 464.-8603, Japan
| | - Shraddha Gupta
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Shinya Takaishi
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Masahiro Yamashita
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
- School of Materials Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
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22
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Su J, Gong Y, Batista ER, Lucena AF, Maria L, Marçalo J, Van Stipdonk MJ, Berden G, Martens J, Oomens J, Gibson JK, Yang P. Unusual Actinyl Complexes with a Redox-Active N,S-Donor Ligand. Inorg Chem 2023. [PMID: 37390399 DOI: 10.1021/acs.inorgchem.3c00990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2023]
Abstract
Understanding the fundamental chemistry of soft N,S-donor ligands with actinides across the series is critical for separation science toward sustainable nuclear energy. This task is particularly challenging when the ligands are redox active. We herein report a series of actinyl complexes with a N,S-donor redox-active ligand that stabilizes different oxidation states across the actinide series. These complexes are isolated and characterized in the gas phase, along with high-level electronic structure studies. The redox-active N,S-donor ligand in the products, C5H4NS, acts as a monoanion in [UVIO2(C5H4NS-)]+ but as a neutral radical with unpaired electrons localized on the sulfur atom in [NpVO2(C5H4NS•)]+ and [PuVO2(C5H4NS•)]+, resulting in different oxidation states for uranium and transuranic elements. This is rationalized by considering the relative energy levels of actinyl(VI) 5f orbitals and S 3p lone pair orbitals of the C5H4NS- ligand and the cooperativity between An-N and An-S bonds that provides additional stability for the transuranic elements.
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Affiliation(s)
- Jing Su
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Yu Gong
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Enrique R Batista
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ana F Lucena
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal
| | - Leonor Maria
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal
| | - Joaquim Marçalo
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal
| | - Michael J Van Stipdonk
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, United States
| | - Giel Berden
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525ED Nijmegen, The Netherlands
| | - Jonathan Martens
- van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525ED Nijmegen, The Netherlands
- van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - John K Gibson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ping Yang
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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23
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Zhang L, Kozhevnikov A, Schulthess T, Trickey SB, Cheng HP. All-electron APW+lo calculation of magnetic molecules with the SIRIUS domain-specific package. J Chem Phys 2023; 158:234801. [PMID: 37326162 DOI: 10.1063/5.0139497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 05/23/2023] [Indexed: 06/17/2023] Open
Abstract
We report APW+lo (augmented plane wave plus local orbital) density functional theory (DFT) calculations of large molecular systems using the domain specific SIRIUS multi-functional DFT package. The APW and FLAPW (full potential linearized APW) task and data parallelism options and the advanced eigen-system solver provided by SIRIUS can be exploited for performance gains in ground state Kohn-Sham calculations on large systems. This approach is distinct from our prior use of SIRIUS as a library backend to another APW+lo or FLAPW code. We benchmark the code and demonstrate performance on several magnetic molecule and metal organic framework systems. We show that the SIRIUS package in itself is capable of handling systems as large as a several hundred atoms in the unit cell without having to make technical choices that result in the loss of accuracy with respect to that needed for the study of magnetic systems.
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Affiliation(s)
- Long Zhang
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
- Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA
- Center for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, Florida 32611, USA
| | | | | | - S B Trickey
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
- Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA
- Center for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Hai-Ping Cheng
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
- Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA
- Center for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, Florida 32611, USA
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Benner F, La Droitte L, Cador O, Le Guennic B, Demir S. Magnetic hysteresis and large coercivity in bisbenzimidazole radical-bridged dilanthanide complexes. Chem Sci 2023; 14:5577-5592. [PMID: 37265712 PMCID: PMC10231311 DOI: 10.1039/d3sc01562a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 04/10/2023] [Indexed: 06/03/2023] Open
Abstract
A judicious combination of radical ligands innate to diffuse spin orbitals with paramagnetic metal ions elicits strong magnetic exchange coupling which leads to properties important for future technologies. This metal-radical approach aids in effective magnetic communication of especially lanthanide ions as their 4f orbitals are contracted and not readily accessible. Notably, a high spin density on the donor atoms of the radical is required for strong coupling. Such molecules are extremely rare owing to high reactivity rendering their isolation challenging. Herein, we present two unprecedented series of bisbenzimidazole-based dilanthanide complexes [(Cp*2Ln)2(μ-Bbim)] (1-Ln = Gd, Tb, Dy, Bbim = 2,2'-bisbenzimidazole) and [K(crypt-222)][(Cp*2Ln)2(μ-Bbim˙)] -(2-Ln = Gd, Tb, Dy), where the latter contains the first Bbim3-˙ radical matched with any paramagnetic metal ion. The magnetic exchange constant for 2-Gd of J = -1.96(2) cm-1 suggests strong antiferromagnetic Gd-radical coupling, whereas the lanthanides in 1-Gd are essentially uncoupled. Ab initio calculations on 2-Tb and 2-Dy uncovered coupling strengths of -4.8 and -1.8 cm-1. 1-Dy features open hysteresis loops with a coercive field of Hc of 0.11 T where the single-molecule magnetism can be attributed to the single-ion effect due to lack of coupling. Excitingly, pairing the effective magnetic coupling with the strong magnetic anisotropy of Dy results in magnetic hysteresis with a blocking temperature TB of 5.5 K and coercive field HC of 0.54 T, ranking 2-Dy as the second best dinuclear single-molecule magnet containing an organic radical bridge. A Bbim4- species is formed electrochemically hinting at the accessibility of Bbim-based redox-active materials.
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Affiliation(s)
- Florian Benner
- Department of Chemistry, Michigan State University 578 South Shaw Lane East Lansing Michigan 48824 USA
| | - Léo La Droitte
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226 F-35000 Rennes France
| | - Olivier Cador
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226 F-35000 Rennes France
| | - Boris Le Guennic
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226 F-35000 Rennes France
| | - Selvan Demir
- Department of Chemistry, Michigan State University 578 South Shaw Lane East Lansing Michigan 48824 USA
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Hossack C, Abdul F, Cahill C, Besson C. Tuning the optical and magnetic properties of lanthanide single-ion magnets using nitro-functionalized trispyrazolylborate ligands. Dalton Trans 2023; 52:7336-7351. [PMID: 37183775 DOI: 10.1039/d3dt01018j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We report the synthesis, crystal structures, photophysical and magnetic properties of 11 novel lanthanide complexes with the asymmetrically functionalized trispyrazolylborate ligand 4-nitrotrispyrazolylborate, 4-NO2Tp-: [Ln(4-NO2Tp)3] (Ln = La-Dy, except Pm). In-depth photophysical characterization of the ligands via luminescence, reflectance and absorption spectroscopic techniques, decay lifetimes, quantum yields supported by time-dependent density functional theory (TD-DFT) and natural bond order (NBO) analysis reveal that n-NO2Tp- ligands are dominated by intra-ligand charge transfer (ILCT) transitions and that second-sphere interactions are critical to the stabilization of the T1 state of n-NO2Tp- ligands and hence their ability to sensitize Ln3+ emission. The luminescence properties of the complexes indicate that 4-NO2Tp- is a poor sensitizer of Ln3+ emission, unlike 3-NO2Tp-. Moreover, [Nd(4-NO2Tp)3] (crystallized as a hexane solvate) displays single-molecule magnet (SMM) properties, with longer relaxation times and larger barrier than the non-functionalized [NdTp3], attributed to the addition of the NO2-group and subsequent rigidification of the molecular structure.
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Affiliation(s)
- Christopher Hossack
- Department of Chemistry, The George Washington University, 800 22nd Street, NW, Washington, D.C. 20052, USA.
| | - Folasade Abdul
- Department of Chemistry, The George Washington University, 800 22nd Street, NW, Washington, D.C. 20052, USA.
| | - Christopher Cahill
- Department of Chemistry, The George Washington University, 800 22nd Street, NW, Washington, D.C. 20052, USA.
| | - Claire Besson
- Department of Chemistry, The George Washington University, 800 22nd Street, NW, Washington, D.C. 20052, USA.
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26
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Yan H, Wu B, Wei J, Zhang WX. Insight into the Ligand-to-Ligand Charge-Transfer Process in Rare-Earth-Metal Diradical Complexes. Inorg Chem 2023; 62:8052-8057. [PMID: 37184543 DOI: 10.1021/acs.inorgchem.3c00900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
While a ligand-to-ligand charge-transfer (LLCT) process is an important way to understand the interactions between metal-bridged radicals for late-transition-metal complexes, there is little clear and evident observation of the LLCT process for rare-earth-metal complexes. In this work, rare-earth-metal diradical complexes supported by diazabutadiene (DAD) ligands [(DAD)2RE(BH4)] [RE = Yb (1), Sm (2)] were synthesized and studied. The coordination geometries of 1 and 2 are different due to the different ionic radii. Reduction of 1 or 2 generated monoradical complexes, with one of their DAD radical anions being reduced. In all of the complexes, Sm and Yb remain at the 3+ valence state. In their UV-vis spectra, the LLCT transition of 1 could be clearly observed, but complex 2 did not show the same transition. These results could be related to the geometric structures of the complexes as well as exchange coupling between diradicals, thus clearly expanding the model for late-transition-metal-bridged diradicals to rare-earth systems experimentally.
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Affiliation(s)
- Haihan Yan
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare-earth Materials Chemistry and Applications, and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Botao Wu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare-earth Materials Chemistry and Applications, and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Junnian Wei
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare-earth Materials Chemistry and Applications, and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wen-Xiong Zhang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare-earth Materials Chemistry and Applications, and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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27
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Li HD, Wu SG, Tong ML. Lanthanide-radical single-molecule magnets: current status and future challenges. Chem Commun (Camb) 2023; 59:6159-6170. [PMID: 37129902 DOI: 10.1039/d2cc07042a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In the field of molecular magnetism, the lanthanide-radical (Ln-Rad) method has become one of the most appealing tactics for introducing strong magnetic interactions and has spurred on the booming development of heterospin single-molecule magnets (SMMs). The article is a timely retrospect on the research progress of Ln-Rad heterospin systems and special attention is invested on low dimensional Ln-Rad compounds with SMM behavior, primarily concerning with nitrogen-based radicals, semiquinone and nitroxide radicals. Rational design, molecular structures, magnetic behaviors and magneto-structural correlations are highlighted. Meanwhile, particular attention is focused on the influence of exchange couplings on the dynamic magnetic properties, with the purpose of helping to guide the design of prospective radical-based Ln-SMMs.
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Affiliation(s)
- Hong-Dao Li
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
- Department of Chemistry and Chemical Engineering, Taiyuan Institute of Technology, Taiyuan 030008, China
| | - Si-Guo Wu
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
| | - Ming-Liang Tong
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
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28
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Jiang N, Nakritskaia DD, Xie J, Ramanathan A, Varganov SA, La Pierre HS. Tuning symmetry and magnetic blocking of an exchange-coupled lanthanide ion in isomeric, tetrametallic complexes: [LnCl 6(TiCp 2) 3]. Chem Sci 2023; 14:4302-4307. [PMID: 37123176 PMCID: PMC10132101 DOI: 10.1039/d2sc06263a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 03/23/2023] [Indexed: 05/02/2023] Open
Abstract
The synthesis and magnetic properties of two pairs of isomeric, exchange-coupled complexes, [LnCl6(TiCp2)3] (Ln = Gd, Tb), are reported. In each isomeric pair, the central lanthanide ion adopts either a pseudo-octahedral (O-Ln) or trigonal prismatic geometry (TP-Ln) yielding complexes with C 1 or C 3h molecular symmetry, respectively. Ferromagnetic exchange coupling is observed in TP-Ln as indicated by the increases in χ m T below 30 K. For TP-Gd, a fit to the susceptibility reveals ferromagnetic coupling between the Gd3+ ion and the Ti3+ ions (J = 2.90(1) cm-1). In contrast to O-Tb, which shows no single-molecule magnetic behavior, the TP-Tb complex presents slow magnetic relaxation with a 100s-blocking temperature of 2.3 K and remanent magnetization at zero field up to 3 K. The calculated electronic structures of both compounds imply that trigonal prismatic geometry of TP-Tb is critical to the observed magnetic behavior.
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Affiliation(s)
- Ningxin Jiang
- School of Chemistry and Biochemistry, Georgia Institute of Technology Atlanta Georgia 30332-0400 USA
| | | | - Jiaze Xie
- Department of Chemistry, University of Chicago Chicago Illinois 60637 USA
| | - Arun Ramanathan
- School of Chemistry and Biochemistry, Georgia Institute of Technology Atlanta Georgia 30332-0400 USA
| | - Sergey A Varganov
- Department of Chemistry, University of Nevada Reno Nevada 89557-0216 USA
| | - Henry S La Pierre
- School of Chemistry and Biochemistry, Georgia Institute of Technology Atlanta Georgia 30332-0400 USA
- Nuclear and Radiological Engineering and Medical Physics Program, School of Mechanical Engineering, Georgia Institute of Technology Atlanta Georgia 30332-0400 USA
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29
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Zhang P, Nabi R, Staab JK, Chilton NF, Demir S. Taming Super-Reduced Bi 23- Radicals with Rare Earth Cations. J Am Chem Soc 2023; 145:9152-9163. [PMID: 37043770 PMCID: PMC10141245 DOI: 10.1021/jacs.3c01058] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Here, we report the synthesis of two new sets of dibismuth-bridged rare earth molecules. The first series contains a bridging diamagnetic Bi22- anion, (Cp*2RE)2(μ-η2:η2-Bi2), 1-RE (where Cp* = pentamethylcyclopentadienyl; RE = Gd (1-Gd), Tb (1-Tb), Dy (1-Dy), Y (1-Y)), while the second series comprises the first Bi23- radical-containing complexes for any d- or f-block metal ions, [K(crypt-222)][(Cp*2RE)2(μ-η2:η2-Bi2•)]·2THF (2-RE, RE = Gd (2-Gd), Tb (2-Tb), Dy (2-Dy), Y (2-Y); crypt-222 = 2.2.2-cryptand), which were obtained from one-electron reduction of 1-RE with KC8. The Bi23- radical-bridged terbium and dysprosium congeners, 2-Tb and 2-Dy, are single-molecule magnets with magnetic hysteresis. We investigate the nature of the unprecedented lanthanide-bismuth and bismuth-bismuth bonding and their roles in magnetic communication between paramagnetic metal centers, through single-crystal X-ray diffraction, ultraviolet-visible/near-infrared (UV-vis/NIR) spectroscopy, SQUID magnetometry, DFT and multiconfigurational ab initio calculations. We find a πz* ground SOMO for Bi23-, which has isotropic spin-spin exchange coupling with neighboring metal ions of ca. -20 cm-1; however, the exchange coupling is strongly augmented by orbitally dependent terms in the anisotropic cases of 2-Tb and 2-Dy. As the first examples of p-block radicals beneath the second row bridging any metal ions, these studies have important ramifications for single-molecule magnetism, main group element, rare earth metal, and coordination chemistry at large.
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Affiliation(s)
- Peng Zhang
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Rizwan Nabi
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jakob K Staab
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Nicholas F Chilton
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Selvan Demir
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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30
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Xie J, Han J, Huang X, Jin C, Li L, Sutter JP. Enhancing the Magnetization Blocking Energy of Biradical-Metal System by Merging Discrete Complexes into One-Dimensional Chains. Chemistry 2023; 29:e202203852. [PMID: 36562658 DOI: 10.1002/chem.202203852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/24/2022]
Abstract
The reaction of nitronyl nitroxide biradical NITPhMeImbis [5-(2-methylimidazole)-1,3-bis(1-oxyl-3'-oxido-4',4',5',5'-tetramethyl-4,5-hydro-1H-imidazol-2-yl)-benzene] with Ln(hfac)3 ⋅ 2H2 O and Cu(hfac)2 (hfac=hexafluoroacetylacetonate), led to two series of 2p-3d-4f complexes, namely, nona-spin clusters, [Ln2 Cu3 (hfac)12 (NITPhMeImbis)2 ] (Ln=Gd 1, Dy 2), or one-dimensional chains [LnCu2 (hfac)7 (NITPhMeImbis)] (Ln=Y 3, Dy 4, Tb 5) depending on the temperature of the reaction. All five complexes contain a biradical-Ln unit in which the biradical chelates the LnIII ion by the means of one aminoxyl (i. e. NO) group of each NIT unit. For the discrete complexes, a Cu(hfac)2 links two biradical-Ln units via one of the remaining NO groups, while for the chain compounds, the two remaining NO groups of the biradical-Ln moiety are each coordinated to a Cu(hfac)2 unit to form a 1D coordination polymer. Moreover, a terminal Cu(hfac)2 unit is coordinated to the imidazole-N atom of the NITPhMeImbis ligand. Spin dynamics investigations evidenced the onset of slow relaxation of the magnetization for 2, whereas 4 and 5 exhibit a typical single-chain magnet behavior. This highlights the vital role of the 1D spin correlation in the blocking of the magnetization. These results illustrate that from the same basic building blocks, magnetic relaxation can be carefully modulated by structural adjustments.
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Affiliation(s)
- Junfang Xie
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Jing Han
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Xiaohui Huang
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Chaoyi Jin
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Licun Li
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Jean-Pascal Sutter
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, 31077, Toulouse, France
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31
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Swain A, Sharma T, Rajaraman G. Strategies to quench quantum tunneling of magnetization in lanthanide single molecule magnets. Chem Commun (Camb) 2023; 59:3206-3228. [PMID: 36789911 DOI: 10.1039/d2cc06041h] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Enhancing blocking temperature (TB) is one of the holy grails in Single Molecule Magnets(SMMs), as any future potential application in this class of molecules is directly correlated to this parameter. Among many factors contributing to a reduction of TB value, Quantum Tunnelling of Magnetisation (QTM), a phenomenon that is a curse or a blessing based on the application sought after, tops the list. Theoretical tools based on density functional and ab initio CASSCF/RASSI-SO methods have played a prominent role in estimating various spin Hamiltonian parameters and establishing the mechanism of magnetization relaxation in this class of molecules. Particularly, various strategies to quench QTM effects go hand-in-hand with experiments, and different methods proposed to quell QTM effects are scattered in the literature. In this perspective, we have explored various approaches that are proposed in the literature to quench QTM effects, and these include the role of (i) local symmetry of lanthanides, (ii) super-exchange interaction in {3d-4f} complexes, (iii) direct-exchange interaction in {radical-4f} and metal-metal bonded complexes to suppress the QTM, (iv) utilizing external stimuli such as an electric field or pressure to modulate the QTM and (v) avoiding QTM effects by stabilising toroidal states in 4f and {3d-4f} clusters. We believe the strategies summarized here will help to design new-generation SMMs.
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Affiliation(s)
- Abinash Swain
- Department of Chemistry, IIT Bombay, Powai, Mumbai - 400076, India.
| | - Tanu Sharma
- Department of Chemistry, IIT Bombay, Powai, Mumbai - 400076, India.
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32
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Curcella A, Sblendorio D, Rusponi S, Pivetta M, Patthey F, Brune H. Valence Orbitals Driving the Spin Dynamics in a Rare-Earth Single-Atom Magnet. PHYSICAL REVIEW LETTERS 2023; 130:106702. [PMID: 36962040 DOI: 10.1103/physrevlett.130.106702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/17/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
We combine spin-polarized scanning tunneling microscopy with quantum master equation analysis to investigate the spin dynamics of the single atom magnet Dy on graphene/Ir(111). By performing reading and writing experiments, we show that the strongly spin polarized 5d6s valence shells, as well as their intra-atomic exchange coupling to the 4f shell, determine the pathways for magnetization relaxation and thus the spin dynamics. The good quantum number that determines which states are stable and which mechanisms for reversal exist in a given crystal field is the atomic total angular momentum J_{z}^{tot} and not the commonly considered J_{z}^{4f} of the 4f shell only.
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Affiliation(s)
- A Curcella
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - D Sblendorio
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - S Rusponi
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M Pivetta
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - F Patthey
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - H Brune
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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33
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Cyclic [Cu-biRadical]2 Secondary Building Unit in 2p-3d and 2p-3d-4f Complexes: Crystal Structure and Magnetic Properties. Molecules 2023; 28:molecules28062514. [PMID: 36985497 PMCID: PMC10058193 DOI: 10.3390/molecules28062514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/07/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
Employing the new nitronyl nitroxide biradical ligand biNIT-3Py-5-Ph (2-(5-phenyl-3-pyridyl)-bis(4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide)), a 16-spin Cu-radical complex, [Cu8(biNIT-3Py-5-Ph)4(hfac)16] 1, and three 2p-3d-4f chain complexes, {[Ln(hfac)3][Cu(hfac)2]2(biNIT-3Py-5-Ph)2}n (LnⅢ= Gd 2, Tb 3, Dy 4; hfac = hexafluoroacetylacetonate), have been prepared and characterized. X-ray crystallographic analysis revealed in all derivatives a common cyclic [Cu-biNIT]2 secondary building unit in which two bi-NIT-3Py-5-Ph biradical ligands and two CuII ions are associated via the pyridine N atoms and NO units. For complex 1, two such units assemble with four additional CuII ions to form a discrete complex involving 16 S = 1/2 spin centers. For complexes 2–4, the [Cu-biNIT]2 units are linked by LnIII ions via NO groups in a 1D coordination polymer. Magnetic studies show that the coordination of the aminoxyl groups with Cu or Ln ions results in behaviors combining ferromagnetic and antiferromagnetic interactions. No slow magnetic relaxation behavior was observed for Tb and Dy derivatives.
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Blackmore WA, Mattioni A, Corner SC, Evans P, Gransbury GK, Mills DP, Chilton NF. Measurement of the Quantum Tunneling Gap in a Dysprosocenium Single-Molecule Magnet. J Phys Chem Lett 2023; 14:2193-2200. [PMID: 36812166 PMCID: PMC9986949 DOI: 10.1021/acs.jpclett.3c00034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
We perform magnetization sweeps on the high-performing single-molecule magnet [Dy(Cpttt)2][B(C6F5)4] (Cpttt = C5H2tBu3-1,2,4; tBu = C(CH3)3) to determine the quantum tunneling gap of the ground-state avoided crossing at zero-field, finding a value on the order of 10-7 cm-1. In addition to the pure crystalline material, we also measure the tunnel splitting of [Dy(Cpttt)2][B(C6F5)4] dissolved in dichloromethane (DCM) and 1,2-difluorobenzene (DFB). We find that concentrations of 200 or 100 mM [Dy(Cpttt)2][B(C6F5)4] in these solvents increases the size of the tunneling gap compared to the pure sample, despite a similarity in the strength of the dipolar fields, indicating that either a structural or vibrational change due to the environment increases quantum tunneling rates.
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35
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Li H, Jin C, Han J, Xi L, Han X. Distinct Magnetic Relaxation Behaviors in Nitronyl Nitroxide-Based Cocrystalline Supramolecular System with DyIII-O-H⋯O-N Hydrogen Bond. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2023.135284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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36
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Wakizaka M, Sato T, Yoshino Y, Takaishi S, Yamashita M. Intramolecular Ferromagnetism in Di-Nuclear 3 d-Transition-Metal Single-Molecule Magnets by Pseudo-Serial Arrangement. Chemistry 2023; 29:e202203421. [PMID: 36479715 DOI: 10.1002/chem.202203421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/30/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022]
Abstract
Di-nuclear citrate complexes, [CH6 N3 ]2 [M2 (citH)2 (H2 O)4 ] ⋅ 2H2 O (citH4 =citric acid; M=FeII (Fe-2), CoII (Co-2), and NiII (Ni-2)), are synthesized. The ligand, citH3- , is deprotonated only at the three carboxy groups, which is different from the previously reported tetra-nuclear structures with cit4- ligands. Magnetic measurements reveal that these complexes have intramolecular ferromagnetism with J=∼0 cm-1 (Ni-2), 0.02 cm-1 (Co-2), and 0.04 cm-1 (Fe-2). Co-2 and Fe-2 show slow magnetic relaxation, and are field-induced SMMs with activation energy of spin-reversal Ueff =27 cm-1 (Co-2) and 4.2 cm-1 (Fe-2). Density functional theory calculations indicate that the uniaxial anisotropy along the z-axis of each metal ion center forms the pseudo-serial arrangement, leading to intramolecular ferromagnetism via the magnetic dipole interaction. This work demonstrates the creation of ferromagnetic SMMs by the magnetic dipole engineering of 3d di-nuclear metal ion centers.
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Affiliation(s)
- Masanori Wakizaka
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Tetsu Sato
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Yuko Yoshino
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Shinya Takaishi
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Masahiro Yamashita
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan.,School of Materials Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
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Low-Coordinate Mixed Ligand NacNac Complexes of Rare Earth Metals. Molecules 2023; 28:molecules28041994. [PMID: 36838980 PMCID: PMC9965685 DOI: 10.3390/molecules28041994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/12/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
We report the synthesis and characterization of two types of new mixed-ligand rare earth complexes: tetracoordinate (NacNacMes)Ln(BIANdipp) (Ln = Dy (1), Er (2) and Y (3)) and pentacoordinate (NacNacMes)Ln(APdipp)(THF) (Ln = Dy (4), Er (5) and Y (6)). The first three compounds were prepared by the reaction of [(BIANDipp)LnI] with potassium β-diketiminate. The salt metathesis of β-diketiminato-supported rare earth dichlorides (NacNacMes)LnCl2(THF)2 with sodium o-amidophenolate results in compounds 4-6. The crystal structures of complexes 1-6 were determined by single-crystal analysis. The combination of bulky monoanionic N-mesityl-substituted β-diketiminates with sterically hindered redox-active ligands led to the very low coordination numbers of rare earths and strong distortion of the chelate ligands.
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Ziółkowska A, Witwicki M. Understanding the Exchange Interaction between Paramagnetic Metal Ions and Radical Ligands: DFT and Ab Initio Study on Semiquinonato Cu(II) Complexes. Int J Mol Sci 2023; 24:ijms24044001. [PMID: 36835412 PMCID: PMC9959031 DOI: 10.3390/ijms24044001] [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: 12/07/2022] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023] Open
Abstract
The exchange coupling, represented by the J parameter, is of tremendous importance in understanding the reactivity and magnetic behavior of open-shell molecular systems. In the past, it was the subject of theoretical investigations, but these studies are mostly limited to the interaction between metallic centers. The exchange coupling between paramagnetic metal ions and radical ligands has hitherto received scant attention in theoretical studies, and thus the understanding of the factors governing this interaction is lacking. In this paper, we use DFT, CASSCF, CASSCF/NEVPT2, and DDCI3 methods to provide insight into exchange interaction in semiquinonato copper(II) complexes. Our primary objective is to identify structural features that affect this magnetic interaction. We demonstrate that the magnetic character of Cu(II)-semiquinone complexes are mainly determined by the relative position of the semiquinone ligand to the Cu(II) ion. The results can support the experimental interpretation of magnetic data for similar systems and can be used for the in-silico design of magnetic complexes with radical ligands.
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Affiliation(s)
- Aleksandra Ziółkowska
- Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, F. Joliot-Curie 14, 50-283 Wroclaw, Poland
- Correspondence:
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Interplay of Anisotropic Exchange Interactions and Single-Ion Anisotropy in Single-Chain Magnets Built from Ru/Os Cyanidometallates(III) and Mn(III) Complex. Molecules 2023; 28:molecules28031516. [PMID: 36771182 PMCID: PMC9921754 DOI: 10.3390/molecules28031516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/08/2023] Open
Abstract
Two novel 1D heterobimetallic compounds {[MnIII(SB2+)MIII(CN)6]·4H2O}n (SB2+ = N,N'-ethylenebis(5-trimethylammoniomethylsalicylideneiminate) based on orbitally degenerate cyanidometallates [OsIII(CN)6]3- (1) and [RuIII(CN)6]3- (2) and MnIII Schiff base complex were synthesized and characterized structurally and magnetically. Their crystal structures consist of electrically neutral, well-isolated chains composed of alternating [MIII(CN)6]3- anions and square planar [MnIII(SB2+)]3+ cations bridged by cyanide groups. These -ion magnetic anisotropy of MnIII centers. These results indicate that the presence of compounds exhibit single-chain magnet (SCM) behavior with the energy barriers of Δτ1/kB = 73 K, Δτ2/kB = 41.5 K (1) and Δτ1/kB = 51 K, Δτ2 = 27 K (2). Blocking temperatures of TB = 2.8, 2.1 K and magnetic hysteresis with coercive fields (at 1.8 K) of 8000, 1600 Oe were found for 1 and 2, respectively. Theoretical analysis of the magnetic data reveals that their single-chain magnet behavior is a product of a complicated interplay of extremely anisotropic triaxial exchange interactions in MIII(4d/5d)-CN-MnIII fragments: -JxSMxSMnx-JySMySMny-JzSMzSMnz, with opposite sign of exchange parameters Jx = -22, Jy = +28, Jz = -26 cm-1 and Jx = -18, Jy = +20, Jz = -18 cm-1 in 1 and 2, respectively) and single orbitally degenerate [OsIII(CN)6]3- and [RuIII(CN)6]3- spin units with unquenched orbital angular momentum in the chain compounds 1 and 2 leads to a peculiar regime of slow magnetic relaxation, which is beyond the scope of the conventional Glaubers's 1D Ising model and anisotropic Heisenberg model.
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Liao PY, Liu Y, Ruan ZY, Wang HL, Shi CG, Deng W, Wu SG, Jia JH, Tong ML. Magnetic and Luminescent Dual Responses of Photochromic Hexaazamacrocyclic Lanthanide Complexes. Inorg Chem 2023; 62:1075-1085. [PMID: 36625763 DOI: 10.1021/acs.inorgchem.2c02868] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Herein, hexaazamacrocyclic ligand LN6 was employed to construct a series of photochromic rare-earth complexes, [Ln(LN6)(NO3)2](BPh4) [1-Ln, Ln = Dy, Tb, Eu, Gd, Y; LN6 = (3E,5E,10E,12E)-3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane-3,5,10,12-tetraene]. The behavior of photogenerated radicals of hexaazamacrocyclic ligands was revealed for the first time. Upon 365 nm light irradiation, complexes 1-Ln exhibit photochromic behavior induced by photogenerated radicals according to EPR and UV-vis analyses. Static and dynamic magnetic studies of 1-Dy and irradiated product 1-Dy* indicate weak ferromagnetic interactions among DyIII ions and photogenerated LN6 radicals, as well as slow magnetization relaxation behavior under a 2 kOe applied field. Further fitting analyses show that the magnetization relaxation in 1-Dy* is markedly different from 1-Dy. Time-dependent fluorescence measurements reveal the characteristic luminescence quenching dynamics of lanthanide in the photochromic process. Especially for irradiated product 1-Eu*, the luminescence is almost completely quenched within 5 min with a quenching efficiency of 98.4%. The results reported here provide a prospect for the design of radical-induced photochromic lanthanide single-molecule magnets and will promote the further development of multiresponsive photomagnetic materials.
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Affiliation(s)
- Pei-Yu Liao
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Yang Liu
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Ze-Yu Ruan
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Hai-Ling Wang
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Chen-Guang Shi
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Wei Deng
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Si-Guo Wu
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Jian-Hua Jia
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Ming-Liang Tong
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
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David G, Ferré N, Le Guennic B. Consistent Evaluation of Magnetic Exchange Couplings in Multicenter Compounds in KS-DFT: The Recomposition Method. J Chem Theory Comput 2023; 19:157-173. [PMID: 36475691 DOI: 10.1021/acs.jctc.2c01022] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The use of broken-symmetry calculations in Kohn-Sham density functional theory has offered an affordable route to study magnetic exchange couplings in transition-metal-based compounds. However, computing this property in compounds exhibiting several couplings is still challenging and especially due to the difficulties to overcome the well-known problem of spin contamination. Here, we present a new and general method to compute magnetic exchange couplings in systems featuring several spin sites. To provide a consistent spin decontamination of J values, our strategy exploits the decomposition method of the magnetic exchange coupling proposed by Coulaud et al. and generalizes our previous work on diradical compounds where the overall magnetic exchange coupling is defined as the sum of its three main and properly extracted physical contributions (direct exchange, kinetic exchange, and spin polarization). In this aim, the generalized extraction of all contributions is presented to systems with multiple spin sites bearing one unpaired electron. This is done by proposing a new paradigm to treat the kinetic exchange contribution, which proceeds through monorelaxations of the magnetic orbitals. This method, so-called the recomposition method, is applied to a compound featuring three Cu(II) ions with a linear arrangement and to a recently synthesized complex containing a Cu4O4 cubane unit presenting an unusual magnetic behavior.
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Affiliation(s)
- Grégoire David
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000Rennes, France
| | - Nicolas Ferré
- Aix-Marseille Univ, CNRS, ICR, 13013Marseille, France
| | - Boris Le Guennic
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000Rennes, France
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Roy S, Paul S, Misra A. A Theoretical Account of the Coupling between Metal- and Ligand-centred Spins. Chemphyschem 2023; 24:e202200889. [PMID: 36622254 DOI: 10.1002/cphc.202200889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/04/2023] [Accepted: 01/09/2023] [Indexed: 01/10/2023]
Abstract
This study addresses the magnetic interaction between paramagnetic metal ions and the radical ligands taking the [CuII (hfac)2 (imVDZ)] and [MII (hfac)2 (pyDTDA)] (imVDZ=1,5-dimethyl-3-(1-methyl-2-imidazolyl)-6-oxoverdazyl; hfac=(1,1,1,5,5,5)hexafluroacetylacetonate; pyDTDA=4-(2'-pyridyl)-1,2,3,5-dithiadiazolyl), (M=Cu, Ni, Co, Fe, Mn) compounds as reference systems. The coupling between the metal and ligand spins is quantified in terms of the exchange coupling constant (J) in the platform of density functional theory (DFT) and the wave function-based complete active space self-consistent field (CASSCF) method. Application of DFT and broken symmetry (BS) formalism results ferromagnetic coupling for all the transition metal complexes except the Mn(II) complex. This DFT-BS prediction of magnetic nature matches with the experimental finding for all the complexes other than the Fe(II)-pyDTDA complex, for which an antiferromagnetic coupling between high spin iron and the thiazyl ligand has been reported. However, evaluation of spin state energetics through the multiconfigurational wave function-based method produces the S=3/2 ground spin state for the iron-thiazyl in parity with experiment. Electronic structure analyses find the overlap between the metal- and ligand-based singly occupied molecular orbitals (SOMOs) to be one of the major reasons attributing to different extent of exchange coupling in the systems under investigation.
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Affiliation(s)
- Sriparna Roy
- Department of Chemistry, University of North Bengal, Siliguri, Darjeeling , 734013, India
| | - Satadal Paul
- Department of Chemistry, Bangabasi Morning College, 19 R.C Sarani, Kolkata, 700009, India
| | - Anirban Misra
- Department of Chemistry, University of North Bengal, Siliguri, Darjeeling , 734013, India
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Kumar Sahu P, Kharel R, Shome S, Goswami S, Konar S. Understanding the unceasing evolution of Co(II) based single-ion magnets. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Domański M, van Leusen J, Metzelaars M, Kögerler P, Grochala W. Ag(II) as Spin Super-Polarizer in Molecular Spin Clusters. J Phys Chem A 2022; 126:9618-9626. [PMID: 36521028 PMCID: PMC9806831 DOI: 10.1021/acs.jpca.2c06032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Using quantum mechanical calculations, we examine magnetic (super)exchange interactions in hypothetical, chemically reasonable molecular coordination clusters containing fluoride-bridged late transition metals or selected lanthanides, as well as Ag(II). By referencing to analogous species comprising closed-shell Cd(II), we provide theoretical evidence that the presence of Ag(II) may modify the magnetic properties of such systems (including metal-metal superexchange) to a surprising degree, specifically both coupling sign and strength may markedly change. Remarkably, this happens in spite of the fact that the fluoride ligand is the least susceptible to spin polarization among all monoatomic ligands known in chemistry. In an extreme case of an oxo-bridged Ni(II)2 complex, the presence of Ag(II) leads to a nearly 17-fold increase of magnetic superexchange and switching from antiferro (AFM)- to ferromagnetic (FM) coupling. Ag(II)─with one hole in its d shell that may be shared with or transferred to ligands─effectively acts as spin super-polarizer, and this feature could be exploited in spintronics and diverse molecular devices.
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Affiliation(s)
- Mateusz Domański
- Center
of New Technologies, University of Warsaw, Zwirki i Wigury 93, 02089Warsaw, Poland
| | - Jan van Leusen
- Institut
für Anorganische Chemie, RWTH Aachen
University, 52056Aachen, Germany
| | - Marvin Metzelaars
- Institut
für Anorganische Chemie, RWTH Aachen
University, 52056Aachen, Germany
| | - Paul Kögerler
- Institut
für Anorganische Chemie, RWTH Aachen
University, 52056Aachen, Germany,
| | - Wojciech Grochala
- Center
of New Technologies, University of Warsaw, Zwirki i Wigury 93, 02089Warsaw, Poland,
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Abstract
Three decades of research in molecular nanomagnets have raised their magnetic memories from liquid helium to liquid nitrogen temperature thanks to a wise choice of the magnetic ion and coordination environment. Still, serendipity and chemical intuition played a main role. In order to establish a powerful framework for statistically driven chemical design, here we collected chemical and physical data for lanthanide-based nanomagnets, catalogued over 1400 published experiments, developed an interactive dashboard (SIMDAVIS) to visualise the dataset, and applied inferential statistical analysis. Our analysis shows that the Arrhenius energy barrier correlates unexpectedly well with the magnetic memory. Furthermore, as both Orbach and Raman processes can be affected by vibronic coupling, chemical design of the coordination scheme may be used to reduce the relaxation rates. Indeed, only bis-phthalocyaninato sandwiches and metallocenes, with rigid ligands, consistently present magnetic memory up to high temperature. Analysing magnetostructural correlations, we offer promising strategies for improvement, in particular for the preparation of pentagonal bipyramids, where even softer complexes are protected against molecular vibrations.
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Pospieszna-Markiewicz I, Fik-Jaskółka MA, Hnatejko Z, Patroniak V, Kubicki M. Synthesis and Characterization of Lanthanide Metal Ion Complexes of New Polydentate Hydrazone Schiff Base Ligand. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238390. [PMID: 36500479 PMCID: PMC9736465 DOI: 10.3390/molecules27238390] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/11/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022]
Abstract
The new homodinuclear complexes of the general formula [Ln2L3(NO3)3] (where HL is newly synthesized 2-((2-(benzoxazol-2-yl)-2-methylhydrazono)methyl)phenol and Ln = Sm3+ (1), Eu3+ (2), Tb3+ (3a, 3b), Dy3+ (4), Ho3+ (5), Er3+ (6), Tm3+ (7), Yb3+ (8)), have been synthesized from the lanthanide(III) nitrates with the polydentate hydrazone Schiff base ligand. The flexibility of this unsymmetrical Schiff base ligand containing N2O binding moiety, attractive for lanthanide metal ions, allowed for a self-assembly of these complexes. The compounds were characterized by spectroscopic data (ESI-MS, IR, UV/Vis, luminescence) and by the X-ray structure determination of the single crystals, all of which appeared to be different solvents. The analytical data suggested 2:3 metal:ligand stoichiometry in these complexes, and this was further confirmed by the structural results. The metal cations are nine-coordinated, by nitrogen and oxygen donor atoms. The complexes are two-centered, with three oxygen atoms in bridging positions. There are two types of structures, differing by the sources of terminal (non-bridging) coordination centers (group A: two ligands, one nitro anion/one ligand, two nitro anions, group B: three ligands, three anions).
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Wang M, Meng X, Liu N, Zhang YQ, Xu N, Shi W, Cheng P. Two monofluoride-bridged DyIII dimers with different magnetization dynamics. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.107995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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48
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Oxalato as polyatomic coordination center and magnetic coupler in copper(II)-polypyrazole inverse polynuclear complexes and coordination polymers. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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49
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Starikov AG, Starikova AA, Shapovalova SO, Guda AA, Soldatov AV. 1,10-Phenanthroline-5,6-dione-bridged FeCo complexes: a DFT investigation of the electronic lability. Struct Chem 2022. [DOI: 10.1007/s11224-022-02077-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Lunghi A, Sanvito S. Computational design of magnetic molecules and their environment using quantum chemistry, machine learning and multiscale simulations. Nat Rev Chem 2022; 6:761-781. [PMID: 37118096 DOI: 10.1038/s41570-022-00424-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2022] [Indexed: 11/09/2022]
Abstract
Having served as a playground for fundamental studies on the physics of d and f electrons for almost a century, magnetic molecules are now becoming increasingly important for technological applications, such as magnetic resonance, data storage, spintronics and quantum information. All of these applications require the preservation and control of spins in time, an ability hampered by the interaction with the environment, namely with other spins, conduction electrons, molecular vibrations and electromagnetic fields. Thus, the design of a novel magnetic molecule with tailored properties is a formidable task, which does not only concern its electronic structures but also calls for a deep understanding of the interaction among all the degrees of freedom at play. This Review describes how state-of-the-art ab initio computational methods, combined with data-driven approaches to materials modelling, can be integrated into a fully multiscale strategy capable of defining design rules for magnetic molecules.
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