Field-Induced Single-Ion Magnets Based on Enantiopure Chiral β‑Diketonate Ligands

A pair of homochiral β-diketonate ligands (+)-3-trifluoroacetyl)­camphor (<i>d</i>-Htfc) and (−)-3-trifluoroacetyl)­camphor (<i>l</i>-Htfc) were used to construct two enantiomeric pairs of Dy­(III) single-ion magnets [Dy­(<i>d</i>-tfc)₃(bpy)]₂ (<i>d</i>-<b>1</b>)/[Dy­(<i>l</i>-tfc)₃(bpy)]₂ (<i>l</i>-<b>1</b>) (bpy = 2,2′-bipyridine) and [Dy­(<i>d</i>-tfc)₃(phen)]·2H₂O (<i>d</i>-<b>2</b>)/[Dy­(<i>l</i>-tfc)₃(phen)] (<i>l</i>-<b>2</b>) (phen = 1,10-phenanthroline). The capping aromatic <i>N</i>,<i>N</i>′-donors have a dramatic influence on the structural and magnetic characteristics of the Dy­(III) β-diketonate enantiomeric pairs: the cocrystal of two homochiral Dy­(III) β-diketonate stereoisomers with the 2,2′-bipyridine ligand was formed, showing field-induced single-ion magnet behaviors with a two-step relaxation process, while no stereoisomerization happened for the homochiral Dy­(III) β-diketonate with the 1,10-phenanthroline coligand, exhibiting a single relaxation process of the magnetization only. The anisotropy barriers of <i>d</i>-<b>1</b> (36.5 and 46.1 K) are slightly smaller than those of <i>l</i>-<b>1</b> (37.0 and 49.3 K), while <i>d</i>-<b>2</b> has a larger energy barrier (30.5 K) with respect to <i>l</i>-<b>2</b> (25.1 K)

Field-Induced Single-Ion Magnets Based on Enantiopure Chiral β‑Diketonate Ligands

A pair of homochiral β-diketonate ligands (+)-3-trifluoroacetyl)­camphor (<i>d</i>-Htfc) and (−)-3-trifluoroacetyl)­camphor (<i>l</i>-Htfc) were used to construct two enantiomeric pairs of Dy­(III) single-ion magnets [Dy­(<i>d</i>-tfc)₃(bpy)]₂ (<i>d</i>-<b>1</b>)/[Dy­(<i>l</i>-tfc)₃(bpy)]₂ (<i>l</i>-<b>1</b>) (bpy = 2,2′-bipyridine) and [Dy­(<i>d</i>-tfc)₃(phen)]·2H₂O (<i>d</i>-<b>2</b>)/[Dy­(<i>l</i>-tfc)₃(phen)] (<i>l</i>-<b>2</b>) (phen = 1,10-phenanthroline). The capping aromatic <i>N</i>,<i>N</i>′-donors have a dramatic influence on the structural and magnetic characteristics of the Dy­(III) β-diketonate enantiomeric pairs: the cocrystal of two homochiral Dy­(III) β-diketonate stereoisomers with the 2,2′-bipyridine ligand was formed, showing field-induced single-ion magnet behaviors with a two-step relaxation process, while no stereoisomerization happened for the homochiral Dy­(III) β-diketonate with the 1,10-phenanthroline coligand, exhibiting a single relaxation process of the magnetization only. The anisotropy barriers of <i>d</i>-<b>1</b> (36.5 and 46.1 K) are slightly smaller than those of <i>l</i>-<b>1</b> (37.0 and 49.3 K), while <i>d</i>-<b>2</b> has a larger energy barrier (30.5 K) with respect to <i>l</i>-<b>2</b> (25.1 K)

Field-Induced Single-Ion Magnets Based on Enantiopure Chiral β‑Diketonate Ligands

A pair of homochiral β-diketonate ligands (+)-3-trifluoroacetyl)­camphor (<i>d</i>-Htfc) and (−)-3-trifluoroacetyl)­camphor (<i>l</i>-Htfc) were used to construct two enantiomeric pairs of Dy­(III) single-ion magnets [Dy­(<i>d</i>-tfc)₃(bpy)]₂ (<i>d</i>-<b>1</b>)/[Dy­(<i>l</i>-tfc)₃(bpy)]₂ (<i>l</i>-<b>1</b>) (bpy = 2,2′-bipyridine) and [Dy­(<i>d</i>-tfc)₃(phen)]·2H₂O (<i>d</i>-<b>2</b>)/[Dy­(<i>l</i>-tfc)₃(phen)] (<i>l</i>-<b>2</b>) (phen = 1,10-phenanthroline). The capping aromatic <i>N</i>,<i>N</i>′-donors have a dramatic influence on the structural and magnetic characteristics of the Dy­(III) β-diketonate enantiomeric pairs: the cocrystal of two homochiral Dy­(III) β-diketonate stereoisomers with the 2,2′-bipyridine ligand was formed, showing field-induced single-ion magnet behaviors with a two-step relaxation process, while no stereoisomerization happened for the homochiral Dy­(III) β-diketonate with the 1,10-phenanthroline coligand, exhibiting a single relaxation process of the magnetization only. The anisotropy barriers of <i>d</i>-<b>1</b> (36.5 and 46.1 K) are slightly smaller than those of <i>l</i>-<b>1</b> (37.0 and 49.3 K), while <i>d</i>-<b>2</b> has a larger energy barrier (30.5 K) with respect to <i>l</i>-<b>2</b> (25.1 K)

Field-Induced Relaxation of Magnetization in a Three-Dimensional LnMOF with the Second Bridging Ligand Squarate

A three-dimensional (3D) dysprosium­(III) metal-organic framework with nicotinate <i>N</i>-oxide (NNO^–) and squarate (C₄O₄^2–) mixed bridging ligands, [Dy­(NNO)­(C₄O₄)­(H₂O)]<i>_n</i> (<b>1</b>), has been hydrothermally synthesized. The dysprosium­(III) ions are linked to each other by the squarate anions to form a unique dysprosium­(III) squarate double-layered network; the NNO^– anions then bridge such layers to complete the 3D framework. Complex <b>1</b> exhibits a two-step relaxation of magnetization under a dc field of 1000 Oe, with effective energy barrier values of 8.5 and 14.3 K, respectively

Syntheses, Crystal Structures, and Magnetic Properties of Two <i>p</i>-<i>tert</i>-Butylsulfonylcalix[4]arene Supported Cluster Complexes with a Totally Disordered Ln₄(OH)₄ Cubane Core

Two new sandwich calix[4]­arene-supported cluster complexes, [Ln₄(OH)₄­(TBSOC)₂­(H₂O)₄­(CH₃OH)₄]­·4H₂O (H₄TBSOC = <i>p</i>-<i>tert</i>-butylsulfonylcalix­[4]­arene; Ln = Dy, <b>1</b>; Ln = Ho, <b>2</b>), have been prepared and characterized. An X-ray crystallographic study reveals that both complexes contain a holistically disordered [Ln₄(OH)₄]⁸⁺ cubane cluster core, which is sandwiched between two antiparallel calixarene macrocycles. Magnetic investigations indicate that complex <b>1</b> displays slow magnetization relaxation typical for single-molecule magnets in the absence of a static applied dc field, with the Δ<i><i>E</i>/k</i>_B parameter of 22.9 K, the largest value for the calixarene-supported pure 4f single-molecule magnets so far, whereas complex <b>2</b> does not show any relaxation of the magnetization above 2 K

Syntheses, Crystal Structures, and Magnetic Properties of Two <i>p</i>-<i>tert</i>-Butylsulfonylcalix[4]arene Supported Cluster Complexes with a Totally Disordered Ln₄(OH)₄ Cubane Core

Two new sandwich calix[4]­arene-supported cluster complexes, [Ln₄(OH)₄­(TBSOC)₂­(H₂O)₄­(CH₃OH)₄]­·4H₂O (H₄TBSOC = <i>p</i>-<i>tert</i>-butylsulfonylcalix­[4]­arene; Ln = Dy, <b>1</b>; Ln = Ho, <b>2</b>), have been prepared and characterized. An X-ray crystallographic study reveals that both complexes contain a holistically disordered [Ln₄(OH)₄]⁸⁺ cubane cluster core, which is sandwiched between two antiparallel calixarene macrocycles. Magnetic investigations indicate that complex <b>1</b> displays slow magnetization relaxation typical for single-molecule magnets in the absence of a static applied dc field, with the Δ<i><i>E</i>/k</i>_B parameter of 22.9 K, the largest value for the calixarene-supported pure 4f single-molecule magnets so far, whereas complex <b>2</b> does not show any relaxation of the magnetization above 2 K

Arraying Octahedral {Cr₂Dy₄} Units into 3D Single-Molecule-Magnet-Like Inorganic Compounds with Sulfate Bridges

Two novel 3D pure inorganic compounds based on [Cr₂Dy₄(μ₄-O)₂(μ₃-OH)₄]¹⁰⁺ cluster units and sulfate anions are presented. Both complexes exhibit single-molecule-magnet (SMM)-like behavior. Permutation of the magnetic moment direction among SMM-like cluster units has a significant effect on the performance of molecular nanomagnets, and directional consistency shows obvious advantages