Asymmetric dinuclear lanthanide(III) complexes from the use of a ligand derived from 2-acetylpyridine and picolinoylhydrazide: synthetic, structural and magnetic studies
| hal.structure.identifier | Department of Chemistry | |
| dc.contributor.author | MANIAKI, Diamantoula | |
| hal.structure.identifier | Centre de Recherche Paul Pascal [CRPP] | |
| hal.structure.identifier | Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB] | |
| dc.contributor.author | PERLEPE, Panagiota | |
| hal.structure.identifier | Department of Chemistry | |
| dc.contributor.author | PILICHOS, Evangelos | |
| hal.structure.identifier | Institut de Ciencies Fotoniques [Castelldefels] [ICFO] | |
| dc.contributor.author | CHRISTODOULOU, Sotirios | |
| hal.structure.identifier | Centre de Recherche Paul Pascal [CRPP] | |
| dc.contributor.author | ROUZIÈRES, Mathieu | |
| hal.structure.identifier | Centre de Recherche Paul Pascal [CRPP] | |
| dc.contributor.author | DECHAMBENOIT, Pierre | |
| hal.structure.identifier | Centre de Recherche Paul Pascal [CRPP] | |
| dc.contributor.author | CLÉRAC, Rodolphe | |
| hal.structure.identifier | Foundation for Research and Technology - Hellas [FORTH] | |
| hal.structure.identifier | Department of Chemistry | |
| dc.contributor.author | PERLEPES, Spyros | |
| dc.date.issued | 2020-07 | |
| dc.identifier.issn | 1420-3049 | |
| dc.description.abstractEn | 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. | |
| dc.language.iso | en | |
| dc.publisher | MDPI | |
| dc.subject.en | Asymmetric dinuclear lanthanide(III) complexes | |
| dc.subject.en | Dysprosium(III) and erbium(III) single-molecule magnets | |
| dc.subject.en | Magnetic properties | |
| dc.subject.en | Metal complexes of N’-(1-(1-pyridin-2-yl)ethylidene)pyridine-2-carbohydrazide | |
| dc.subject.en | Magnetization relaxation pathways | |
| dc.subject.en | Single-crystal X-ray structures | |
| dc.subject.en | asymmetric dinuclear lanthanide(III) complexes | |
| dc.subject.en | dysprosium(III) and erbium(III) single-molecule magnets | |
| dc.subject.en | magnetic properties | |
| dc.subject.en | metal complexes of N'-(1-(1-pyridin- 2-yl)ethylidene)pyridine-2-carbohydrazide | |
| dc.subject.en | magnetization relaxation pathways | |
| dc.subject.en | single-crystal X-ray structures | |
| dc.title.en | Asymmetric dinuclear lanthanide(III) complexes from the use of a ligand derived from 2-acetylpyridine and picolinoylhydrazide: synthetic, structural and magnetic studies | |
| dc.type | Article de revue | |
| dc.identifier.doi | 10.3390/molecules25143153 | |
| dc.subject.hal | Chimie/Matériaux | |
| bordeaux.journal | Molecules | |
| bordeaux.page | 3153 ((23 p.) | |
| bordeaux.volume | 25 | |
| bordeaux.issue | 14 | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-02906220 | |
| hal.version | 1 | |
| hal.popular | non | |
| hal.audience | Internationale | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-02906220v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Molecules&rft.date=2020-07&rft.volume=25&rft.issue=14&rft.spage=3153%20((23%20p.)&rft.epage=3153%20((23%20p.)&rft.eissn=1420-3049&rft.issn=1420-3049&rft.au=MANIAKI,%20Diamantoula&PERLEPE,%20Panagiota&PILICHOS,%20Evangelos&CHRISTODOULOU,%20Sotirios&ROUZI%C3%88RES,%20Mathieu&rft.genre=article |
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