|论文题目||Linear hexanuclear helical dysprosium single-molecule magnets: the effect of axial substitution on magnetic interactions and relaxation dynamics|
|作 者||; Jingjing Lu, Xiaolei Li. Zhenhua Zhu. Shuting Liu. Yang, Qiandian. Jinkui Tang.|
|发表年度||OCT 7 2019|
|卷、期、页码||48; 37; 14062-14068|
The reaction between the rigid Schiff-base ligand H4L ([3,6-bis(2-hydroxy-3-methoxybenzylidene)hydrazinecarbonyl]-pyridazine) and different dysprosium(iii) salts afforded two new linear hexanuclear helical clusters, [Dy6L3(SCN)(6)(DMF)(8)]center dot 4DMF (1), and [Dy6L3(NO3)(6)(DMF)(4)(H2O)(2)]center dot 8DMF (2), which possess a similar Dy-6 core with [Dy6L3(PhCOO)(6)(CH3OH)(6)]center dot 11CH(3)OH center dot H2O (3). Modulation of the axial ligands around Dy-III sites causes different coordination geometries and magnetic interactions, resulting in distinct magnetic relaxation behaviors. Compounds 1 and 2 show typical single-molecule magnet (SMM) properties with effective barriers (U-eff) of 15 and 68 K, respectively, which could greatly profit from strong ferromagnetic interactions compared with compound 3. Presence of a hula-hoop-like geometry of the Dy-III ions and stronger ferromagnetic interactions results in better SMM performance of compound 2 than that of 1.