CRYSTAL STRUCTURE OF THE ISOMORPHOUS COMPLEXES TETRAAQUABIS(2,6-DIHYDROXY-BENZOATO-O)(2,6-DIHYDROXY-BENZOATO-O,O)TERBIUM(III) AND HOLMIUM(III) DIHYDRATE

Syntheses, structural modulation, and slow magnetic relaxation of three dysprosium(III) complexes with mononuclear, dinuclear, and one-dimensional structures

Three mononuclear, dinuclear and one-dimensional dysprosium(III) complexes based on 3-azotriazolyl-2,6-dihydroxybenzoic acid (H₄ATB) of [Dy(H₃ATB)₃]·3H₂O (1), [Dy₂(H₂ATB)₂(H₂DHB)₂(H₂O)₄]·2CH₃CN·5H₂O (2), and [Dy₂(H₂ATB)₂(DCB)(DMF)₂(H₂O)₂]·4DMF (3) were synthesized and structurally characterized by X-ray single crystal diffraction (H₃DHB = 2,6-dihydroxybenzoic acid, H₂DCB = 1,4-dicarboxybenzene). Complex 1 was used as a precursor to synthesize complexes 2 and 3, and 2 was further used to synthesize 3. Complex 1 is a mononuclear complex, in which the Dy(III) ion is in a nine-coordinated structure surrounded by three tridentate chelate H₃ATB^- ligands. Complex 2 displays a dinuclear structure bridged by two μ₂ carboxyl groups of two H₂DHB^- ligands and two μ_1,1-O atoms from the phenolic hydroxyl groups of two H₂ATB^2- ligands. Complex 3 shows a one-dimensional structure formed by two bridging DCB^2- ligands. The magnetic measurements were performed on three complexes 1-3, and they showed different magnetic behavior. Complex 1 shows a field-induced slow magnetic relaxation. Complexes 2 and 3 display distinct slow magnetic relaxation under zero dc field with energy barriers (U_eff) of 26(2) cm^-1 and 11(1) cm^-1, respectively. The magnetic behavior of three complexes 1-3 was investigated by ab initio calculations.

Novel mononuclear Ln complexes with pyrazine-2-carboxylate and acetylacetonate co-ligands: remarkable single molecule magnet behavior of a Yb derivative

A series of novel mononuclear complexes were prepared, and the Yb derivative exhibits the highest Δ_eff/k_B value known for ytterbium complexes.

Tetra-aqua-bis-(2,6-dihy-droxy-benzoato-κO)(2,6-dihy-droxy-benzoato-κO,O)gadolinium(III) dihydrate

In the title compound, [Gd(C₇H₅O₄)₃(H₂O)₄]·2H₂O, the Gd^III ion shows a distorted square anti­prismatic coordination formed by four aqua ligands and four O atoms from the three 2,6-dihy­droxy­benzoate (L) ligands. Two L ligands coordinate the Gd^III ion in a monodentate mode, while the third coordinates it in a bidentate–chelating coordination mode. An extensive three-dimensional O—H⋯O hydrogen-bonding network consolidates the crystal packing.