Synthesis and characterization of isostructural tetranuclear lanthanide complexes [Ln4(μ3-OH)2(ampdH4)2(piv)10]·4CH3CN (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er)

Synthesis, Structures, and Single-Molecule Magnetic Properties of Three Dy2 Complexes

To explore the influences of the subtle structural variations in the ligand backbones on the single-molecule magnetic properties of dinuclear dysprosium(III) complexes, three ligands-H₂ L₁ (H₂ L₁ =N₁ ,N₃ -bis(salicylaldehyde)diethylenetriamine), H₂ L₂ (H₂ L₂ =N₁ ,N₃ -bis(3-methoxysalicylidene)diethylenetriamine), and H₂ L₃ (H₂ L₃ =N₁ ,N₃ -bis(5-chlorosalicyladehyde)diethylenetriamine)-were synthesized and employed to prepare the expected dinuclear dysprosium(III) complexes. The three ligands differ in terms of the substituents at the benzene rings of the salicylaldehyde moieties. The reactions of Dy(NO₃ )₃ ⋅6 H₂ O, pivalic acid, and the ligands H₂ L₁ , H₂ L₂ , and H₂ L₃ generated complexes with the formulae [Dy₂ (L₁ )₂ (piv)₂ ] (1), [Dy₂ (L₂ )₂ (piv)₂ ] (2), and [Dy₂ (L₃ )₂ (piv)₂ ]⋅ 2 MeCN (3), respectively. The purposeful attachment of the functional groups with varied sizes at the benzene rings of the salicylaldehyde backbones resulted in slight differences in the Dy-O-Dy bond angles and the Dy⋅⋅⋅Dy bond lengths in 1-3; consequently, the three complexes exhibited distinct magnetic properties. They all showed slow magnetization relaxation with energy barriers of 40.32 (1), 31.67 (2), and 33.53 K (3). Complete active space self-consistent field (CASSCF) calculations were performed on complexes 1-3 to rationalize the slight discrepancy observed in the magnetic behavior. The calculated results satisfactorily explained the experimental outcomes.

Slow magnetic relaxation in Dy2 and Dy4 complexes of a versatile, trifunctional polydentate N,O-ligand

A binuclear Dy^III complex exhibits slow relaxation of magnetization under an applied dc field, while its tetranuclear counterpart exhibits “true” zero-field SMM behaviour.

Synthesis, luminescence and magnetic properties of tetranuclear lanthanide-based (Eu4, Gd4 and Dy4) clusters

Three analogous tetranuclear lanthanide-containing complexes were isolated, and they exhibit interesting luminescent and magnetic properties.

Reticular Chemistry and the Discovery of a New Family of Rare Earth (4, 8)-Connected Metal-Organic Frameworks with csq Topology Based on RE4(μ3-O)2(COO)8 Clusters

In recent years, the design and discovery of new metal-organic framework (MOF) platforms with distinct structural features and tunable chemical composition has remarkably enhanced by applying reticular chemistry rules and the molecular building block (MBB) approach. We targeted the synthesis of new rare earth (RE)-MOF platforms based on a rectangular-shaped 4-c linker, acting as a rigid organic MBB. Accordingly, we designed and synthesized the organic ligand 1,2,4,5-tetrakis(4-carboxyphenyl)-3,6-dimethyl-benzene (H₄L), in which the two methyl groups attached to the central phenyl ring lock the four peripheral carboxyphenyl groups to an orthogonal/vertical position. We report here a new family of RE-MOFs featuring the novel inorganic building unit, RE₄(μ₃-O)₂ (RE: Y³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, and Yb³⁺), with planar D_2h symmetry. The rigid 4-c linker, H₄L, directs the in situ assembly of the unique 8-c RE₄(μ₃-O)₂(COO)₈ cluster, resulting in the formation of the first (4, 8)-c RE-MOFs with csq topology, RE-csq-MOF-1. The structures of the yttrium (Y-csq-MOF-1) and holmium (Ho-csq-MOF-1) analogues were determined by single-crystal X-ray diffraction analysis. Y-csq-MOF-1 was successfully activated and tested for Xe/Kr separation. The results show that Y-csq-MOF-1 has high isosteric heat of adsorption for Xe (33.8 kJ mol^-1), with high Xe/Kr selectivity (IAST 12.1, Henry 12.9) and good Xe uptake (1.94 mmol g^-1 at 298 K and 1 bar), placing this MOF among the top-performing adsorbents for Xe/Kr separation.

Cu(ii)–Dy(iii) and Co(iii)–Dy(iii) based single molecule magnets with multiple slow magnetic relaxation processes in the Cu(ii)–Dy(iii) complex

Two Cu^II–Dy^III and Co^III–Dy^III dinuclear complexes of a Schiff base ligand (H₃L) exhibit single-molecule magnetic behaviour with multiple slow magnetic relaxation processes for the former.

pH-induced Dy4 and Dy10 cluster-based 1D chains with different magnetic relaxation features

Two novel [Dy₄] and [Dy₁₀] cluster-based 1D chains (1 and 2) were structurally and magnetically characterized, exhibiting different magnetic relaxation behaviors. The results revealed that the different pH values induced large structural and magnetic changes of 1 and 2, and this has rarely been reported in polynuclear Dy-clusters.