Two lanthanide-based dinuclear clusters (Gd-2 and Dy-2) with Schiff base derivatives: Synthesis, structures and magnetic properties

摘要

Two dinuclear lanthanide compounds, [Gd-2(L1)(dbm)(5)] (1) (HL1 = N'-(2-pyridinylmethylene)-2-(hydroxyimino)propanehydrazide), Hdbm = 1, 3-diphenyl-1,3-propanedione), [Dy-2(L2)(2)(dbm)(2)(CH3OH)(2)]center dot 3CH(3)OH (2) (H(2)L2 = 2-[[(4-methyl-2-carboxyl)imino]methyl]-8-hydroxyquinoline) have been successfully synthesized and characterized. Single-crystal X-ray analysis revealed that compounds 1 and 2 both contain two eight-coordinated lanthanide (Ln(III)) ions in the center of them, and adjacent Ln(III) ions in them are linked together by two mu(2)-O atoms, generating into a [Ln(2)O(2)] cluster. The magnetic studies revealed 1 possesses magnetocaloric effect with the maxmium value of - Delta S-m being 17.69 J K-1 kg(-1) for Delta H = 8 KOe at 2.0 K. Alternating-current (ac) magnetic susceptibilities studies revealed that 2 displays slow magnetic relaxation behaviors with the anisotropic barrier Delta E/k(B) = 18.3 K and tau(0) = 7.34 x 10(-7) s under 5000 Oe.