A Dy₂ single-molecule magnet with benzoate anions and phenol-O⁻ bridging groups

Abstract

A Dy2 single-molecule magnet, namely [Dy2(H3L)2(PhCOO)4]·4H2O (1), was obtained from the reaction of Dy(PhCOO)3 with 1,5-bis(2-hydroxy-3-methoxybenzylidene)carbonohydrazide (H4L). Each Dy(III) ion is located in the chelating pocket [DyO8N] formed by the carboxyl-O, phenol-O, carbohydrazide-O and carbohydrazide-N, forming a tricapped trigonal prism configuration. The Dy(III) centers are bridged by the benzoate anions with μ2:η(1),η(2) coordination mode and the phenol-O(-) groups in the form of μ1:η(2), respectively. The appearance of frequency-dependent out-of-phase (χ''M) signals indicates that 1 displays single-molecule magnet (SMM) behaviour. Fits of the ac data gave an energy barrier (Ueff) of 42.7 K with a pre-exponential factor (τ0) of 1.31 × 10(-7) s. The structure-property relationship of some selected Dy2 paradigmatic compounds was further discussed.

Hysteresis in a bimetallic holmium complex: A synergy between electronic and nuclear magnetic interactions

“…The same type of hysteresis has been recently evidenced by Chen et al in a pentagonal Ho(III) complex [11]. The study of the interplay of the SMM behavior in dinuclear complexes is quite recent and is mainly focused on Dy-containing complexes [12][13][14][15][16][17][18][19]. Magnetization hysteresis loops have been observed in a series of Ln(III) [20] and in several bimetallic Dy(III) [21][22][23][24].…”

Fine‐Tuning Ligand Fields with Schiff‐Base Ligands in Dy2 Compounds

“…In fact, the previously reported coordination compound Na[Dy 2 (Hovph) 2 (µ 2 ‐OH)(OH)(H 2 O) 5 ] 3 · Cl · 3H 2 O also exhibits a Dy 2 (µ‐O) 3 core, and does not exhibit any out‐of‐phase ac signal, similarly to 3 . Thus, a significant change in the µ‐O bridges between the metal centers will modify the overlap between the magnetic orbitals of the Dy ions, thus influencing the magnetic interactions for 1 and 3 . On the other hand, no characteristic slow magnetic relaxation was observed for the isomorphic compound 2 .…”

Single‐Molecule Magnetism in Dy2 Cluster Based on a Schiff Base Ligand

“…Although complex 1 joins a big family of Dy 2 clusters, [ 11–40 ] none of the complexes crystallized from the DME solution, and the DME oxygen atom also serves as a coordination site in 1 . These features indicate the improvement of the synthesis method and the structural novelty of complexes 1 and 2 .…”

“…[ 4–10 ] Among all the lanthanide‐based SMMs, [Ln 2 ]SMMs have attracted significant attention of the chemists and physicists in the world. [ 11–40 ] There are many reasons for this, for example, (i) compared with other polynuclear clusters, the synthesis of [Ln 2 ] is easier to control; (ii) the structure‐property relationships of the dinuclear systems could be easily investigated by modifying the functional groups of the ligands; (iii) in studying the magnetic interaction between two lanthanide atoms, they represent the simplest structural units; and (iv) it is relatively convenient to determine the possible orientation of anisotropy in the dinuclear system. We believe that Ln 2 is the most basic structure in explaining the nature of single molecule magnets (such as the relationship between single ion relaxation and molecular entity relaxation; the influence of magnetic interaction on magnetization relaxation, the possible orientation of anisotropy).…”