Modulating the magnetization dynamics of four phenoxo-O bridged Dy2 complexes based on a Schiff base derived from 8-hydroxyquinoline

Four novel -O bridged dinuclear Dy-2 clusters have been synthesized successfully by utilizing an 8-hydroxyquinoline (8-HQ) Schiff base ligand and four different co-ligands: [Dy-2(bfa)(2)(L)(2)(H2O)(2)]4CH(3)OH (1), [Dy-2(TTA)(2)(L)(2)(H2O)(2)]4CH(3)OH (2), [Dy-2(acac)(2)(L)(2)(H2O)(2)]2H(2)O (3) and [Dy-2(PhCOO)(2)(L)(2)(H2O)(2)] (4) (Hbfa = benzoyl trifluoroacetylacetone, HTTA = thiophene trifluoroacetylacetone, Hacac = acetylacetone, PhCOOH = benzoic acid, H2L = 2-[(4-pyridinebenzoylhydrazone)methyl]-8-hydroxyquinoline). Magnetic studies show that only complex 1 exhibits SMM behavior under a zero dc field with a magnetic relaxation barrier of 68.89 K. When a dc field of 1500 Oe is applied, the value of E/k(B) increases to 72.63 K. The different dynamic magnetic behaviors of the four Dy-2 complexes mainly originate from the tiny changes of the coordination environment and magnetic coupling interaction of the central ions caused by the different co-ligands. Meanwhile, it proves that the co-ligands play an important role in modulating the magnetic properties of Dy-SMMs based on 8-HQ derivatives.