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Using a novel tricompartmental hydrazone ligand, a set of trinuclear Dy3 complexes has been isolated and structurally characterized. Complexes Dy3 ⋅ Cl, Dy3 ⋅ Br, and Dy3 ⋅ ClO4 feature a similar overall topology but different anions (Cl−, Br−, or ClO4−) in combination with exogenous OH− and solvent co‐ligands, which is found to translate into very different magnetic properties. Complex Dy3 ⋅ Cl shows a double relaxation process with fast quantum tunneling of the magnetization, probably related to the structural disorder of μ2‐OH− and μ2‐Cl− co‐ligands. Relaxation of the magnetization is slowed down for Dy3 ⋅ Br and Dy3 ⋅ ClO4, which do not show any structural disorder. In particular, fast quantum tunneling is suppressed in case of Dy3 ⋅ ClO4, resulting in an energy barrier of 341 K and magnetic hysteresis up to 3.5 K; this makes Dy3 ⋅ ClO4 one of the most robust air‐stable trinuclear SMMs. Magneto‐structural relationships of the three complexes are analyzed and rationalized with the help of CASSCF/RASSI‐SO calculations. [ABSTRACT FROM AUTHOR]

Three CoII complexes, [Co2(H2L1)2](ClO4)4·4CH3OH (1), [Co2(H4L2)2](ClO4)4 (2) and [Co4(H4L2)4](ClO4)8 (3), were constructed by the self-assembly of the symmetrical dihydrazone ligands H2L1 and H4L2 with CoII ions under different synthetic conditions. The fish-bone-like complex 1 was obtained using the ligand H2L1 in methanol via the solvothermal method, while the self-assembly of H4L2 with CoII ions is solvent-dependent, producing the fish-bone-like complex 2 and [2 × 2] grid-like complex 3. Magnetic susceptibility measurements and theoretical calculations reveal that the large negative D values for the three complexes stem from their easy-axis magnetic anisotropy. Ac magnetic susceptibility measurements disclosed field-induced slow magnetic relaxation behaviors and the presence of Raman and/or direct processes of the three complexes at various applied dc fields. [ABSTRACT FROM AUTHOR]

Using a novel tricompartmental hydrazone ligand, a set of trinuclear Dy 3 complexes has been isolated and structurally characterized. Complexes Dy 3  ⋅ Cl, Dy 3  ⋅ Br, and Dy 3  ⋅ ClO 4 feature a similar overall topology but different anions (Cl - , Br - , or ClO 4 - ) in combination with exogenous OH - and solvent co-ligands, which is found to translate into very different magnetic properties. Complex Dy 3  ⋅ Cl shows a double relaxation process with fast quantum tunneling of the magnetization, probably related to the structural disorder of μ 2 -OH - and μ 2 -Cl - co-ligands. Relaxation of the magnetization is slowed down for Dy 3  ⋅ Br and Dy 3  ⋅ ClO 4 , which do not show any structural disorder. In particular, fast quantum tunneling is suppressed in case of Dy 3  ⋅ ClO 4 , resulting in an energy barrier of 341 K and magnetic hysteresis up to 3.5 K; this makes Dy 3  ⋅ ClO 4 one of the most robust air-stable trinuclear SMMs. Magneto-structural relationships of the three complexes are analyzed and rationalized with the help of CASSCF/RASSI-SO calculations., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Photosensitive lanthanide-based single-molecule magnets (Ln-SMM) are very attractive for their potential applications in information storage, switching, and sensors. However, the light-driven structural transformation in Ln-SMMs hardly changes the coordination number of the lanthanide ion. Herein, for the first time it is reported that X-ray (λ=0.71073 Å) irradiation can break the coordination bond of Dy-OH 2 in the three-dimensional (3D) metal-organic framework Dy 2 (amp 2 H 2 ) 3 (H 2 O) 6  ⋅ 4H 2 O (MDAF-5), in which the {Dy 2 (OPO) 2 } dimers are cross-linked by dianthracene-phosphonate ligands. The structural transformation proceeds in a single-crystal-to-single-crystal (SC-SC) fashion, forming the new phase Dy 2 (amp 2 H 2 ) 3 (H 2 O) 4  ⋅ 4H 2 O (MDAF-5-X). The phase transition is accompanied by a significant change in magnetic properties due to the alteration in coordination geometry of the Dy III ion from a distorted pentagonal bipyramid in MDAF-5 to a distorted octahedron in MDAF-5-X., (© 2022 Wiley-VCH GmbH.)

Three Co II complexes, [Co 2 (H 2 L 1 ) 2 ](ClO 4 ) 4 ·4CH 3 OH (1), [Co 2 (H 4 L 2 ) 2 ](ClO 4 ) 4 (2) and [Co 4 (H 4 L 2 ) 4 ](ClO 4 ) 8 (3), were constructed by the self-assembly of the symmetrical dihydrazone ligands H2L1 and H4L2 with Co II ions under different synthetic conditions. The fish-bone-like complex 1 was obtained using the ligand H2L1 in methanol via the solvothermal method, while the self-assembly of H4L2 with Co II ions is solvent-dependent, producing the fish-bone-like complex 2 and [2 × 2] grid-like complex 3. Magnetic susceptibility measurements and theoretical calculations reveal that the large negative D values for the three complexes stem from their easy-axis magnetic anisotropy. Ac magnetic susceptibility measurements disclosed field-induced slow magnetic relaxation behaviors and the presence of Raman and/or direct processes of the three complexes at various applied dc fields.