Slow magnetic dynamics in centrosymmetric didysprosium and equilateral triangular tridysprosium molecules

摘要

Single-molecule magnets (SMMs) with higher nuclearity provide opportunity for understanding the inherent nature of magnetic dynamics that are not limited to mononuclear SMMs. Herein, centrosymmetric [Dy-2(L)(2)(9-AC)(4)(MeOH)(2)]2CH(2)Cl(2)2H(2)O (1, where 9-AC = anthracene-9-carboxylate) and equilateral triangular [Dy-3(OH)(OMe)(L)(3)(dbm)(3)](OH)3CH(2)Cl(2)7H(2)O (2, where dbm = dibenzoylmethane anion) were isolated using the Schiff-base ligand 4-(anthracen-9-yl)-2-((quinolin-8-ylimino)methyl)phenol (HL). Static and dynamic magnetic measurements reveal that 1 and 2 display slow magnetic relaxation under zero and applied dc field, respectively. The magnetization relaxation for 1 is dominated by a Raman process due to its non-negligible transverse anisotropy. Complex 2 exhibits field-induced SMM behavior with a reversal barrier of 56 cm(-1). By means of ab initio calculations and magnetic measurements, the multiple relaxation regime in 2 was investigated. We suggest that Orbach and Raman mechanisms dominate in the high/low temperature domains, respectively.