A new <i>β</i>-diketonate Dy(III) single‒ion magnet featuring multiple magnetic relaxation processes

<p>A <i>β</i>-diketonate mononuclear dysprosium compound, [Dy(TFNB)₃(bpy)] (<b>1</b>) (TFNB = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, bpy = 2,2′-bipyridine), has been prepared and structurally and magnetically characterized. X-ray crystallographic analysis reveals that <b>1</b> contains two crystallographically equivalent Dy(III) ions of which the eight-coordinate geometries uniformly behave as distorted square antiprismatic configurations (<i>D</i>_4d). Magnetic investigations demonstrate that <b>1</b> displays dual relaxation processes of SMMs behavior with the effective barrier (Δ<i>E</i>/<i>k</i>_B) of 23.44 K under 1200 Oe DC field, corresponding to the coexistence of two metal centers in the structure of the compound. The comparative studies of some Dy(III)-based SIMs with TFNB ligand have been conducted as well. <i>Ab initio</i> studies demonstrate that the Kramers doublet ground state is predominantly axial with the <i>g</i>_z tensors of two Dy(III) fragments matching the Ising-limit factor (20) anticipated for the pure <i>M</i>_J = ±15/2 state.</p

Single-Ion-Magnet Behavior in a Two-Dimensional Coordination Polymer Constructed from Co^II Nodes and a Pyridylhydrazone Derivative

A novel two-dimensional (2D) coordination polymer, [Co­(ppad)₂]_<i>n</i> (<b>1</b>), resulted from the assembly of Co^II ions based on a versatile ligand termed <i>N</i>³-(3-pyridoyl)-3-pyridinecarboxamidrazone. Alternating/direct-current magnetic studies of compound <b>1</b> indicate that the spatially separated high-spin Co^II ions act as single-ion magnets (SIMs). The present work represents the first case of a 2D Co^II-based SIM composed of a monocomponent organic spacer

Solvent-Induced Syntheses, Crystal Structures, Magnetic Properties, and Single-Crystal-to-Single-Crystal Transformation of Azido-Cu(II) Coordination Polymers with 2‑Naphthoic Acid as Co-ligand

Based on the solvent-induced effect, three new azido-copper coordination polymers[Cu­(2-na)­(N₃)] (<b>1</b>), [Cu­(2-na)­(N₃)] (<b>2</b>), and [Cu­(2-na)­(N₃)­(C₂H₅OH)] (<b>3</b>) (where 2-na = 2-naphthoic acid)have been successfully prepared. Structure analysis shows that the Cu­(II) cations in compounds <b>1</b>–<b>3</b> present tetra-, penta-, and hexa-coordination geometries, respectively. Compound <b>1</b> is a well-isolated one-dimensional (1D) chain with the EO-azido group, while <b>2</b> is an isomer of <b>1</b> and exhibits a two-dimensional (2D) layer involving the EE-azido group. Thermodynamically, density functional theory (DFT) calculation reveals that <b>2</b> occupies the stable state and <b>1</b> locates in the metastable state. Compound <b>3</b> consists of a 1D chain with triple bridging mode, which is derived from <b>1</b>, and undergoes a single-crystal-to-single-crystal transformation by soaking in ethanol solvent; the powdery product of <b>1</b>, namely <b>1b</b>, could be yielded after the dealcoholization of compound <b>3</b>. Magnetic measurements indicate that compounds <b>1</b>–<b>3</b> perform strong intrachain ferromagnetic interactions, experiencing long-range magnetic ordering and slow magnetic relaxation. Compound <b>1</b> features the metamagnetic behavior with a transition temperature of 15 K, while <b>2</b> and <b>3</b> display spin glass behavior with the phase transition temperatures of 15 and 12 K, respectively. Magneto-structure relationships are investigated as well

Solvent-Induced Syntheses, Crystal Structures, Magnetic Properties, and Single-Crystal-to-Single-Crystal Transformation of Azido-Cu(II) Coordination Polymers with 2‑Naphthoic Acid as Co-ligand

Based on the solvent-induced effect, three new azido-copper coordination polymers[Cu­(2-na)­(N₃)] (<b>1</b>), [Cu­(2-na)­(N₃)] (<b>2</b>), and [Cu­(2-na)­(N₃)­(C₂H₅OH)] (<b>3</b>) (where 2-na = 2-naphthoic acid)have been successfully prepared. Structure analysis shows that the Cu­(II) cations in compounds <b>1</b>–<b>3</b> present tetra-, penta-, and hexa-coordination geometries, respectively. Compound <b>1</b> is a well-isolated one-dimensional (1D) chain with the EO-azido group, while <b>2</b> is an isomer of <b>1</b> and exhibits a two-dimensional (2D) layer involving the EE-azido group. Thermodynamically, density functional theory (DFT) calculation reveals that <b>2</b> occupies the stable state and <b>1</b> locates in the metastable state. Compound <b>3</b> consists of a 1D chain with triple bridging mode, which is derived from <b>1</b>, and undergoes a single-crystal-to-single-crystal transformation by soaking in ethanol solvent; the powdery product of <b>1</b>, namely <b>1b</b>, could be yielded after the dealcoholization of compound <b>3</b>. Magnetic measurements indicate that compounds <b>1</b>–<b>3</b> perform strong intrachain ferromagnetic interactions, experiencing long-range magnetic ordering and slow magnetic relaxation. Compound <b>1</b> features the metamagnetic behavior with a transition temperature of 15 K, while <b>2</b> and <b>3</b> display spin glass behavior with the phase transition temperatures of 15 and 12 K, respectively. Magneto-structure relationships are investigated as well