Zero Field SMM Behavior and Magnetic Refrigeration in Rare Heterometallic Double Stranded Helicates of Cu₂Ln₂ (Ln = Dy, Tb, Gd)

Abstract

The strategic design and synthesis of new double stranded helical structures, namely [Cu 2 Ln 2 (H 2 L 1 ) 2 (L 2 ) 2 (OMe)-(NO 3 )]·8MeOH (1: Ln = Dy III ), [Cu 2 Ln 2 (H 2 L 1 ) 2 (L 2 ) 2 (H 2 O)(OMe)-(NO 3 )]·xH 2 O·7MeOH (2: Ln = Tb III , x = 0.5; 3: Ln = Gd III , x = 1) and [Cu 2 Ln 2 (HL 1 ) 2 (L 2 ) 2 (MeOH) 2 ]·xMeOH (4: Ln = Dy III , x = 8.5; 5: Ln = Tb III , x = 8; 6: Ln = Gd III , x = 8.66), has been achieved by using a flexible helical ligand and a rigid tridentate ligand. Butanedihydrazide-bridged bis(3-ethoxysalicylaldehyde) (H 4 L 1 ) was used as a primary ligand due to its flexible nature for constructing the helical strand and another rigid tridentate ligand, 2-salicylideneaminophenol (H 2 L 2 ), was used to accommodate the transition metal. The two series of complexes are analogous and differ only in terms of coordination geometry around the [a]

Two Types of Hexanuclear Partial Tetracubane [Ni4Ln2] (Ln = Dy, Tb, Ho) Complexes of Thioether-Based Schiff Base Ligands: Synthesis, Structure, and Comparison of Magnetic Properties

“…Such a strategy was successful in providing many Ni-4f and Cu-4f complexes of varying nuclearity . Phenol-based Schiff bases are well-known to provide heterometallic coordination clusters from one-pot reactions involving a mixture of 3d and 4f metal ion salts and ligands. ,− …”

Heterometallic Hexanuclear [Cu2Ln4] Complexes Showing Zero‐field SMM Behaviour and Magnetocaloric Effect

“…Generally, Cu‐lanthanide units (especially Cu−Gd) in polynuclear complexes are found to exhibit ferromagnetic interaction among them [1a–d,f–h,20] . Several schematic pathways have already been proposed to explain the origin of the interaction between the magnetic centres in such complexes [1c,6a,8a,11a,16b,d,20–21] . BS‐DFT calculation shows the presence of both ferromagnetic and antiferromagnetic exchange coupling between Cu II and Ln III centres in the complexes.…”

Coordination-Directed Self-Assembly of Functional Polynuclear Lanthanide Supramolecular Architectures

“…With the simultaneous addition of Cu 2+ and Ln III ions, 3d−4f heterometallic double strand helicates M31-Dy and M32-Dy were prepared (Figure 50). 326 The coordination environment of the metal centers exerted changes in their magnetic properties. Magnetic susceptibility measurements (ac field) suggested that these heterometallic helicates demonstrated slow magnetic relaxation and magnetic refrigeration behaviors.…”