Slow magnetic dynamics in centrosymmetric didysprosium and equilateral triangular tridysprosium molecules

Abstract

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 [Dy₂(L)₂(9-AC)₄(MeOH)₂]·2CH₂Cl₂·2H₂O (1, where 9-AC = anthracene-9-carboxylate) and equilateral triangular [Dy₃(OH)(OMe)(L)₃(dbm)₃](OH)·3CH₂Cl₂·7H₂O (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.