Regulating the magnetic property through structual transformation and multifunctional magnetic bistable materials attract increasing interst in the research area of molecular magnets. Herein, we have obtained a two-dimensional Dy3+ metal-organic...
Comprehensive SummaryThe reaction of DyCl3⋅6H2O with a rigid diacylhydrazone ligand (H2L) afforded a trinuclear precursor [Dy3L2Cl3(H2O)2(CH3OH)]Cl2⋅3CH3OH (1). The replacement of the Cl– ions and the coordinating solvents by the aryloxides ligands (Lx)– yields three trinuclear complexes [Dy3L2(Lx)5]⋅nsol (x = 1,2‐naphthol (2); x = 2,7‐hydroxycoumarin (3); and x = 3, phenol (4)). In complexes 2—4, two end Dy3+ centers adopt almost identical N4O4 coordination sphere of D6h geometry while the central one adopts N4O5 coordination sphere in Cs geometry. Magnetic measurements reveal weak antiferromagnetic interactions in the hydrated samples 2e—4e and two‐step slow relaxation process under zero dc field with effective energy barriers Ueff of 439 and 91 K, 353 and 40 K, 466 and 89 K for SR and FR in 2e—4e, respectively. Such dynamic magnetic behaviour for 4 persists in the magnetically diluted sample of 4@Y. Complex 4 possesses the short Dy‐Oaryloxide bond distance of 2.055(18) Å, and the largest Ueff among the reported linear trinuclear dysprosium complexes. Moreover, the functionalized aryloxides ligands (Lx)– show photoluminescence via intramolecular energy transfer, making 2e—4e luminescent Dy3+ SMMs with high energy barriers.
The elaborate design and synthesis of three isomorphous cyclic octanuclear clusters [Fe 4 Ln 4 (L) with the Schiff base ligand H 2 L (2-(hydroxyimino)propionic acid (dipyridin-2ylmethylene)hydrazide) have been achieved. The compartmental ligand H 2 L has N 3 -inner and N 2 O-outer coordination sites, which chelate low-spin Fe(III) and Ln(III), respectively. The remaining coordination sites around the rare-earth ions are occupied by nitrate ions and water molecules. This is the first report on the use of a hydrazine group within a ligand to connect Fe III and Ln III ions, which can not only stabilize the skeleton of the molecular ring but also transmit a weak antiferromagnetic interaction between Fe III and Ln III (Ln = Dy, Gd) ions. ac magnetic susceptibility measurements under an external applied dc field of 1600 Oe reveal the SMM behavior of complex 1 with U eff = 25.8 K. The magnitude of the magnetic exchange between Fe(III) and Gd(III) in complex 2 is evaluated to be 2J FeGd = −0.324 cm −1 ; meanwhile, complex 2 shows a moderate magnetocaloric effect (MCE) with −ΔS m = 17.06 J kg −1 K −1 under 5 T at 2 K.
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