Heterometallic Octanuclear Ni^II₄Ln^III₄ (Ln = Y, Gd, Tb, Dy, Ho, Er) Complexes Containing Ni^II₂Ln^III₂O₄ Distorted Cubane Motifs: Synthesis, Structure, and Magnetic Properties

Abstract

The reaction of 2-methoxy-6-[{2-(2-hydroxyethylamino)ethylimino}methyl] phenol (LH 3 ) with lanthanide metal salts followed by the addition of nickel acetate allowed isolation of a family of octanuclear complexes, [Ni 4 Ln 4 (μ 2 -OH) 2 (μ 3 -OH) 4 (μ-OOCCH 3 ) 8 (LH 2 ) 4 ]·(OH) 2 · x H 2 O. Single crystal X-ray diffraction studies of these complexes reveal that their central metallic core consists of two tetranuclear [Ni 2 Ln 2 O 4 ] cubane subunits fused together by acetate and hydroxide bridges. The magnetic study of these complexes reveals a ferromagnetic interaction between the Ln III and the Ni II center. The magnitude of exchange coupling between the Ni II and Ln III center, parametrized from the magnetic data of the Gd analogue, gives J = +0.86 cm –1 . The magneto caloric effect, studied for the Ni II 4 Gd III 4 complex, shows a maximum of magnetic entropy change, −Δ S m = 22.58 J kg –1 K –1 at 3 K for an applied external field of 5 T.

Heterometallic 3d–4f Complexes as Single‐Molecule Magnets

“…Using a different multi‐site compartmental ligand, 2‐methoxy‐6‐[{2‐(2‐hydroxyethylamino)ethylimino}methyl] phenol, (L 24 H 3 ), octameric [Ni II 4 Ln III 4 ( μ ‐OH) 2 ( μ 3 ‐OH) 4 ( μ ‐OOCCH 3 ) 8 (L 24 H 2 ) 4 ](OH) 2 complexes [Ln III =Y III ( 120 ), Gd III ( 121 ), Tb III ( 122 ), Dy III ( 123 ), Er III ( 124 ) and Ho III ( 125 )] were prepared . The octanuclear framework consists of two tetranuclear [Ni II 2 Ln III 2 O 4 ] cubane subunits (Figure ).…”

“…Using ad ifferent multi-site compartmental ligand, (123), Er III (124)a nd Ho III (125)] were prepared. [77] The octanuclearf rameworkc onsists of two tetranuclear [Ni II 2 Ln III 2 O 4 ] cubane subunits ( Figure 17). None of these complexes show SMM behavior (even in the presence of 1000 Oe externald c field).…”

Construction of A sqc6 Topology Ni‐Gd Framework Employing 2,2’‐Phosphinico‐dibenzoate and Oxalate: Structure and Magnetic Properties

“…The temperature dependence of the magnetic susceptibility product χ M T for compound 1 is presented in Figure 4. At room temperature, the measured χ M T value for compound 1 is determined to be 14.09 emu K mol −1 , lower than the spin‐only value expected for the presence of six Ni(II) and one Gd(III) ions [40] . Based on magnetic analysis points, due to the relatively weak delivery of magnetic coupling by a monodentate bridging carboxylate ligand, the magnetic behavior of compound 1 can be interpreted as a superposition of a pentanuclear {Ni 4 Gd} unit and a binuclear Ni 2 (ox) unit.…”

Structure and assembly mechanism of a centipede-shaped high-nuclear Dy14Cu12heterometallic nanocluster

“…S10 †. The magnetization of 1 has a sharp increase in the low field range with a subsequent much slower increase in the high field range, reaching a value of 27.78 Nμ B at 70 kOe and 1.8 K. 51,76 The M vs. H T −1 isotherms collected at different temperatures are not superimposed, which revealed possible anisotropy and/or low energy states for 1 . The magnetic hysteresis loops at 2 K for 1 were not apparent, which is shown in Fig.…”