Electro-activity and magnetic switching in lanthanide-based single-molecule magnets

Cador, Olivier; Guennic, Boris Le; Pointillart, Fabrice

doi:10.1039/c9qi00875f

Cited by 69 publications

(54 citation statements)

References 196 publications

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“…The experimental data were fitted to the van Vleck analytical expression of the susceptibility derived from the following isotropic Heisenberg spin Hamiltonian: H = −2J(S Gd1 •S Gd2 ). The best-fit parameters obtained are J/k B = −0.020(6) K and g = 2.023 (1). The observed antiferromagnetic exchange interaction is very weak as a consequence of the shielded 4f orbitals that have little overlap with the orbitals of the bridging oxygen atoms.…”

Section: Ac Magnetic Susceptibilty Studiesmentioning

confidence: 91%

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Asymmetric Dinuclear Lanthanide(III) Complexes from the Use of a Ligand Derived from 2-Acetylpyridine and Picolinoylhydrazide: Synthetic, Structural and Magnetic Studies

et al. 2020

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A family of four Ln(III) complexes has been synthesized with the general formula [Ln2(NO3)4(L)2(S)] (Ln = Gd, Tb, Er, and S = H2O; 1, 2 and 4, respectively/Ln = Dy, S = MeOH, complex 3), where HL is the flexible ditopic ligand N’-(1-(pyridin-2-yl)ethylidene)pyridine-2-carbohydrazide. The structures of isostructural MeOH/H2O solvates of these complexes were determined by single-crystal X-ray diffraction. The two LnIII ions are doubly bridged by the deprotonated oxygen atoms of two “head-to-head” 2.21011 (Harris notation) L¯ ligands, forming a central, nearly rhombic {LnIII2(μ-OR)2}4+ core. Two bidentate chelating nitrato groups complete a sphenocoronal 10-coordination at one metal ion, while two bidentate chelating nitrato groups and one solvent molecule (H2O or MeOH) complete a spherical capped square antiprismatic 9-coordination at the other. The structures are critically compared with those of other, previously reported metal complexes of HL or L¯. The IR spectra of 1–4 are discussed in terms of the coordination modes of the organic and inorganic ligands involved. The f-f transitions in the solid-state (diffuse reflectance) spectra of the Tb(III), Dy(III), and Er(III) complexes have been fully assigned in the UV/Vis and near-IR regions. Magnetic susceptibility studies in the 1.85–300 K range reveal the presence of weak, intramolecular GdIII∙∙∙GdIII antiferromagnetic exchange interactions in 1 [J/kB = −0.020(6) K based on the spin Hamiltonian Ĥ = −2J(ŜGd1∙ ŜGd2)] and probably weak antiferromagnetic LnIII∙∙∙LnIII exchange interactions in 2–4. Ac susceptibility measurements in zero dc field do not show frequency dependent out-of-phase signals, and this experimental fact is discussed for 3 in terms of the magnetic anisotropy axis for each DyIII center and the oblate electron density of this metal ion. Complexes 3 and 4 are Single-Molecule Magnets (SMMs) and this behavior is optimally observed under external dc fields of 600 and 1000 Oe, respectively. The magnetization relaxation pathways are discussed and a satisfactory fit of the temperature and field dependencies of the relaxation time τ was achieved considering a model that employs Raman, direct, and Orbach relaxation mechanisms.

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Section: Ac Magnetic Susceptibilty Studiesmentioning

confidence: 91%

“…Devices in the future, such as hard disks, will use components made from molecules instead of the traditional silicon-based electronics [1]. Molecules capable of retaining their magnetization in a given direction were discovered in the 1990s with the now famous {Mn III 8 Mn IV 4 } acetate complex [2].…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Dinuclear Lanthanide(III) Complexes from the Use of a Ligand Derived from 2-Acetylpyridine and Picolinoylhydrazide: Synthetic, Structural and Magnetic Studies

et al. 2020

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“…TTF and its derivatives have been widely studied as electron‐donor components for conductive, optoelectronic, and magnetic materials [6] . The electroactivity of the TTF moiety has been used as a switch to modulate the magnetic moment between metal nodes in molecular structure and extended solids [2g,h, 6g,h] . Utilizing MOFs, the function of TTF could be employed in porous solids [7] .…”

Section: Figurementioning

confidence: 99%

Rare‐Earth Metal Tetrathiafulvalene Carboxylate Frameworks as Redox‐Switchable Single‐Molecule Magnets

Yuan

et al. 2020

Chemistry A European J

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Using the redox‐active tetrathiafulvalene tetrabenzoate (TTFTB4−) as the linker, a series of stable and porous rare‐earth metal–organic frameworks (RE‐MOFs), [RE9(μ3‐OH)13(μ3‐O)(H2O)9(TTFTB)3] (1‐RE, where RE=Y, Sm, Gd, Tb, Dy, Ho, and Er) were constructed. The RE9(μ3‐OH)13(μ3‐O) (H2O)9](CO2)12 clusters within 1‐RE act as segregated single‐molecule magnets (SMMs) displaying slow relaxation. Interestingly, upon oxidation by I2, the S=0 TTFTB4− linkers of 1‐RE were converted into S= TTFTB.3− radical linkers which introduced exchange‐coupling between SMMs and modulated the relaxation. Furthermore, the SMM property can be restored by reduction in N,N‐dimethylformamide. These results highlight the advantage of MOFs in the construction of redox‐switchable SMMs.

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“…In this context, the 1,10-phenantroline-5,6-dione (L) appears as a promising multifunctional ligand since it combines two potential coordination sites with electro-activity [28,29], leading to the design of potential multi-properties compounds, such as a combination of spin crossover and valence tautomerism, as has recently been proposed from a computational point of view [30]. Its electro-activity could be exploited to modulate the physical properties as a function of its oxidation state, i.e., to design redox magnetic and photo-emissive switches, as already published with other redox-active ligands [31][32][33]. The L ligand was employed to design both pure 4f [34][35][36][37][38][39] and hetero-bimetallic nd4f [40][41][42] coordination complexes to study their biological activities and photo-physical properties.…”

Section: Introductionmentioning

confidence: 98%

Dysprosium Single-Molecule Magnets Involving 1,10-Phenantroline-5,6-dione Ligand

et al. 2020

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The two mononuclear complexes of the formula [Dy(tta) 3 (L)] (1) and [Dy(hfac) 3 (L)] (2) (where tta -= 2-thenoytrifluoroacetylacetonate and hfac -= 1,1,1,5,5,5-hexafluoroacetylacetonate) were obtained from the coordination reaction of the Dy(tta) 3 ·2H 2 O or Dy(hfac) 3 ·2H 2 O units with the 1,10-phenantroline-5,6-dione ligand (L). Their structures have been determined by X-ray diffraction studies on single crystals, and they revealed a supramolecular assembly of tetramers through σ-π interactions. Both complexes displayed a Single-Molecule Magnet (SMM) behavior without an external applied magnetic field. Magnetic relaxation happened through Orbach, Raman and Quantum Tunneling of the Magnetization (QTM). Wavefunction theory calculations were realized to rationalize the magnetic properties.

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Electro-activity and magnetic switching in lanthanide-based single-molecule magnets

Abstract: The present work reviews switching of single-molecule magnetic behaviour achieved through various stimuli such as temperature, light irradiation, redox processes, solvation/desolvation, and magnetic field.

Cited by 69 publications

References 196 publications

Asymmetric Dinuclear Lanthanide(III) Complexes from the Use of a Ligand Derived from 2-Acetylpyridine and Picolinoylhydrazide: Synthetic, Structural and Magnetic Studies

Asymmetric Dinuclear Lanthanide(III) Complexes from the Use of a Ligand Derived from 2-Acetylpyridine and Picolinoylhydrazide: Synthetic, Structural and Magnetic Studies

Rare‐Earth Metal Tetrathiafulvalene Carboxylate Frameworks as Redox‐Switchable Single‐Molecule Magnets

Dysprosium Single-Molecule Magnets Involving 1,10-Phenantroline-5,6-dione Ligand

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