In Situ Reaction and Coordination Site Regulation to Form Binuclear Dysprosium Complexes with Different Connections and Magnetic Properties

Abstract

How to construct and control multinuclear dysprosium clusters with excellent single-molecule magnet (SMM) properties have been a great concern and challenge. Herein, we obtained two pyridine monoacylhydrazone ligands that are isomers of each other by a solvothermal in situ reaction, and the position of the N coordination site on the pyridine ring was controlled to achieve two binuclear dysprosium-based complexes with different SMM performance and cluster core connections. Specifically, 2-pyridinecarboxylhydrazide and 1-methyl-1H-imidazole-2-carbaldehyde undergo an in situ Schiff base reaction at 80 °C solvothermal conditions and coordinate with Dy­(NO3)3·6H2O to obtain a binuclear dysprosium complex [Dy2(L1)2(NO3)4(H2O)]­(HL1)·(H2O)2(CH3CN)2 (1) with a Dy2O2 cluster nucleus. In addition, the mononuclear dysprosium complex [Dy­(L2)­(NO3)2(H2O)2]·CH3CN (2) and binuclear dysprosium complex [Dy­(L2)2(NO3)]2·4CH3CN (3) were obtained by changing 2-pyridinecarboxylhydrazide to 3-pyridinecarboxylhydrazide and adjusting the solvent ratio of the reaction system. In the structure of binuclear dysprosium complex 3, Dy···Dy is not bridged by O atoms and has a long distance. Magnetic studies show that complexes 1–3 all exhibit field-induced SMM behaviors. Under the external field, the inversion energy barriers and relaxation times of complexes 1–3 are U eff = 22.40(6) K and τ0 = 7.33(1) × 10–5 s (1), U eff = 16.38(1) K and τ0 = 1.25(6) × 10–4 s (2), and U eff = 59.25(9) K and τ0 = 6.30(1) × 10–5 s (3), respectively. This work demonstrates that the design of the coordination sites for organic ligands is an effective strategy to tune the SMM properties of the polynuclear dysprosium complexes. It also provides a vivid example for the directional construction of multinuclear dysprosium complexes with SMM behaviors by in situ reactions in a black-box system.

[2 + 2] cycloaddition and its photomechanical effects on 1D coordination polymers with reversible amide bonds and coordination site regulation

“…According to the literature, the coordination mode of the CPs changes due to the different locations of the coordination site. 51,52 As shown in Scheme S3,† H 2 MeOip exhibited multiple coordination modes and deprotonation types. 53 After studying the structure of 1 , we aimed to control the position of pyridine N in the ligand 3-ptpa , reduce steric hindrance, and change the coordination mode between H 2 MeOip and the Cd 2+ ions.…”

Lanthanide Complexes with a Potential Docking Spot: Structure and Magnetism

“…As a class of attractive molecular-based magnetic materials, single-molecule magnets (SMMs) show potential applications in ultrahigh density data storage, molecular spintronic devices, and quantum computing. − Lanthanide metal ions (especially Dy­(III) ions) have large magnetic moments and magnetic anisotropy due to their unquenched orbital angular momentum, making them excellent carriers for constructing SMMs. − So far, a series of high-performance dysprosium-based SMMs have been developed, and these Dy­(III) complexes possess high reversal barrier and hysteresis temperature. − As we all know, the combination between metal and ligand defines a precise coordination environment that affects the SMM performance. Therefore, metal ions not only affect the performance of complex SMMs but also the selection of appropriate organic ligands is crucial for the construction of complex SMMs. − A wide variety of organic ligands have emerged for the synthesis of dysprosium-based SMMs, such as Schiff bases, − heteropolyacids, − acylhydrazones, − free radical ligands, and so on. − …”

Perfluoroalkyl Chain Length Effect on Crystal Packing and [LnO8] Coordination Geometry in Lanthanide-Lithium β-Diketonates: Luminescence and Single-Ion Magnet Behavior

“…In this context, the structures having approximately square-antiprismatic or dodecahedral coordination polyhedra are of much interest because of their high potential as SIMs. The magnetic relaxation behavior of these SIMs has been shown to be affected by distortion of the coordination sphere, typically caused by subtle modification of the lattice solvent, auxiliary ligand, and intermolecular interaction [41][42][43][44][45][46][47][48]. Therefore, the anisotropy of the lanthanide ions and their magnetic dynamics are strongly influenced by both the ligand field and coordination geometry [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51].…”