Short Didysprosium Covalent Bond Enables High Magnetization Blocking Temperature of a Direct 4f–4f Coupled Dinuclear Single-Molecule Magnet

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(26), С. 17600 - 17605

Опубликована: Июнь 13, 2024

Coupling two magnetic anisotropic lanthanide ions via a direct covalent bond is an effective way to realize high magnetization blocking temperature of single-molecule magnets (SMMs) by suppressing quantum tunneling (QTM), whereas so far only single-electron lanthanide–lanthanide bonds with relatively large distances are stabilized in which coupling between and the single electron dominates over weak 4f–4f coupling. Herein, we report for first time synthesis short Dy(II)–Dy(II) (3.61 Å) confined inside carbon cage form endohedral metallofullerene Dy2@C82. Such renders strong Dy–Dy antiferromagnetic that effectively quenches QTM at zero field, thus opening up hysteresis 25 K using field sweep rate Oe/s, concomitant 100 s (TB,100s) 27.2 K.

Язык: Английский

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A comprehensive approach for elucidating the interplay between 4fⁿ⁺¹ and 4fⁿ5d¹ configurations in Ln²⁺ complexes

Chemical Science, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

To advance our ability to control the electronic properties of divalent lanthanides, interplay between deformation densities, 4f interelectronic repulsion, and ligand field effects is discussed predict nature their ground states.

Язык: Английский

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Large Hyperfine Coupling Arising from Pseudo-²S Ground States in a Series of Lutetium(II) Metallocene Complexes

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Апрель 9, 2025

The synthesis of molecules with strong coupling between electronic and nuclear spins represents an important challenge in molecular quantum information science. Here, we report the characterization divalent lutetium metallocene complexes Lu(CpMe5)(CpiPr5) (CpMe5 = pentamethylcyclopentadienyl; CpiPr5 pentaisopropylcyclopentadienyl), Lu(CpiPr4Et)2 (CpiPr4Et ethyltetraisopropylcyclopentadienyl), Lu(CpiPr4)2 (CpiPr4 tetraisopropylcyclopentadienyl). structures these complexes, as determined through single-crystal X-ray diffraction, feature a common bent sandwich geometry, average Cp-Lu-Cp angles ranging from 159.9° to 152.6°. Analysis continuous-wave electron paramagnetic resonance (EPR) spectra for reveals nearly isotropic g tensors only slight deviation that free electron. Moreover, extremely large splitting eight-line indicates presence hyperfine coupling, simulations provide constants Aiso 4.38, 4.30, 4.17 GHz across series, where value is found decrease angle becomes more acute. Notably, values are largest yet observed any lanthanide complex. EPR computational analysis show stem s-orbital character─up 41.2%─in corresponding singly occupied orbitals. To our knowledge, this degree s-character orbital reported open-shell isolable These results outline general strategy toward isolation highly doublet ground states.

Язык: Английский

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A tetravalent praseodymium complex with field-induced slow magnetic relaxation

Dalton Transactions, Год журнала: 2024, Номер 53(13), С. 5779 - 5783

Опубликована: Янв. 1, 2024

A tetravalent praseodymium complex with field-induced slow magnetic relaxation is presented.

Язык: Английский

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δ-Bonding modulates the electronic structure of formally divalent nd¹ rare earth arene complexes

Chemical Science, Год журнала: 2024, Номер 15(37), С. 15160 - 15169

Опубликована: Янв. 1, 2024

Landmark advances in rare earth (RE) chemistry have shown that divalent complexes can be isolated with non-Aufbau 4f n {5d/6s}1 electron configurations, facilitating remarkable bonding motifs and magnetic properties. We report a series of bis-tethered arene complexes, [RE(NHAriPr6 )2] (2RE; RE = Sc, Y, La, Sm, Eu, Tm, Yb; NHAriPr6 {N(H)C6H3-2,6-(C6H2-2,4,6-iPr3)2}). Fluid solution EPR spectroscopy gives g iso < 2.002 for 2Sc, 2Y, 2La, consistent formal nd1 calculations reveal metal-arene δ-bonding via mixing nd(x 2-y 2) valence electrons into π* orbitals. Experimental calculated UV-Vis-NIR spectroscopic properties 2Y show minor structural changes markedly alter the metal d(x contribution to SOMO. This contrasts where d-based resides non-bonding orbital. Complexes 2Sm, 2Eu, 2Tm, 2Yb contain highly-localised n+1 ions no appreciable by density functional calculations. These results physicochemical both configurations are nuanced, may controlled through ligand modification, require multi-pronged experimental theoretical approach fully rationalise.

Язык: Английский

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Spin‐State Control in Dysprosium(III) Metallacrown Magnets via Thioacetal Modification

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(31)

Опубликована: Май 3, 2024

Integrating controllable spin states into single-molecule magnets (SMMs) enables precise manipulation of magnetic interactions at a molecular level, but remains synthetic challenge. Herein, we developed 3d-4f metallacrown (MC) magnet [DyNi

Язык: Английский

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Mono(guanidinate) chromium(II) chloride complexes: Selective synthesis and structural characterization

Polyhedron, Год журнала: 2025, Номер unknown, С. 117481 - 117481

Опубликована: Март 1, 2025

Язык: Английский

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Perplexing EPR Signals from 5f³6d¹ U(II) Complexes

Inorganic Chemistry, Год журнала: 2024, Номер 63(6), С. 2945 - 2953

Опубликована: Янв. 27, 2024

Metal complexes with unpaired electrons in orbitals of different angular momentum quantum numbers (e.g., f and d orbitals) are unusual opportunities to study the interactions among these rare. X-band electron paramagnetic resonance (EPR) data were collected at <10 77 K on 10 U(II) 5f36d1 configurations some analogous Ce(II), Pr(II), Nd(II) 4fn5d1 configurations. The compounds unexpectedly display similar two-line axial signals g|| = 2.04 g⊥ 2.00 K. In contrast, 5f4 EPR-silent. Unlike U(II), congenic 4f35d1 complex is Ce(II) a 4f15d1 configuration also EPR-silent, but signal observed for Pr(II) complex, which has 4f25d1 configuration. Whether or not an EPR expected depends coupling between electrons. Since systems be sufficiently strong preclude from configuration, results viewed as unexplained phenomena. However, they do show that samples can differentiated by spectroscopy.

Язык: Английский

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Understanding the Coordination Chemistry and Structural and Photophysical Properties of Eu^II- and Sm^II-Containing Complexes of Hexamethylhexacyclen and Noncyclic Tetradentate Amines

Inorganic Chemistry, Год журнала: 2024, Номер 63(37), С. 16991 - 17004

Опубликована: Сен. 6, 2024

Ligands play a crucial role in supporting or stabilizing the divalent oxidation state of lanthanide metals. To expand range ligands used to chelate ions, we synthesized and studied structural photophysical properties complexes Eu

Язык: Английский

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Guanidinate Yttrium Complexes Containing Bipyridyl and Bis(benzimidazolyl) Radicals

Inorganic Chemistry, Год журнала: 2024, Номер 63(21), С. 9659 - 9669

Опубликована: Апрель 3, 2024

Ancillary ligand scaffolds that sufficiently stabilize a metal ion to allow its coordination an open-shell are scarce, yet their development is essential for next-generation spin-based materials with topical applications in quantum information science. To this end, synthetic challenge must be met: devising molecules enable the binding of redox-active through facile displacement and clean removal weakly coordinating anion. Here, we probe accessibility unprecedented radical-containing rare-earth guanidinate complexes by combining our recently discovered yttrium tetraphenylborate complex [{(Me3Si)2NC(NiPr)2}2Y][(μ-η6-Ph)(BPh3)] ligands 2,2′-bipyridine (bpy) 2,2′-bis(benzimidazole) (Bbim), respectively, under reductive conditions. Our endeavor resulted first evidence contain radicals, namely, mononuclear bipyridyl radical complex, {(Me3Si)2NC(NiPr)2}2Y(bpy•) (1), dinuclear bis(benzimidazolyl) radical-bridged [K(crypt-222)][{(Me3Si)2NC(NiPr)2}2Y]2(μ-Bbim•) (2′). The latter was achieved situ reduction [{(Me3Si)2NC(NiPr)2}2Y]2(μ-Bbim) (2), which isolated from salt metathesis reaction. 1 2 were characterized X-ray crystallography IR UV–vis spectroscopy. Variable-temperature electron paramagnetic resonance spectroscopy applied gain insight into distribution unpaired spin density on 2′. Density functional theory calculations conducted 2′ elucidate further electronic structures. redox activity also probed electrochemical methods.

Язык: Английский

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