Tuning the Magnetic Interactions in Dy(III)₄ Single-Molecule Magnets

Abstract

The study of mononuclear lanthanide-based systems, where the observed single-molecule magnets (SMMs) properties originate from the local description of the magnetic properties of the lanthanide ion, has been widely investigated through the literature. The case of polynuclear SMMs becomes more challenging both experimentally and theoretically due to the complexity of such architectures involving interactions between the magnetic centers. Many efforts have been focused on the understanding of the nature of these interactions and their effects on the SMM properties. In this work, a series of three structurally related tetranuclear dysprosium(III) SMMs, namely, [Dy(L)(OH)(DMF)(NO)]·2(DMF)·(HO) (1), [Dy(L)(OH)(DMF)(tfaa)]·2(CHCN) (2), and [Dy(L)(OH)(DMF)(acac)]·2(DMF) (3) (HL = 2-(2-hydroxy-3-methoxybenzylideneamino)phenol, Htfaa = trifluoroacetylactone, Hacac = acetylacetonate), has been synthesized and investigated. By a fine-tuning of the ligands on the changeable coordination sites in these Dy(III) SMMs, the intramolecular magnetic interactions can be modified, switching from antiferromagnetic (for 1 and 2) to ferromagnetic (for 3). Ab initio calculations support these statements. In addition, the formation of 1 has been analyzed by ESI-MS analysis of the reaction mixture, indicating rather quick and high-yield formation of the [Dy] framework in solution. The combination of experimental work and ab initio calculations offers further insight into the relationship between structures and magnetic properties and sheds light on how to tune magnetic interactions in future polynuclear dysprosium complexes.

Leveraging Surface Siloxide Electronics to Enhance Relaxation Properties of a Single-Molecule Magnet

“…In M1-M3, the main component of g-tensor is almost parallel to Dy-O bond and thus its orientation is mainly driven by negative electrostatic potential associated with the surface siloxide oxygen atom (Figures 2 and S4). [47,48] In M4, the presence of two bound oxygen atoms induces an orientation of the magnetic axis parallel to the surface. Moreover, transition magnetic moment probabilities for M1-M4 reveal that the relaxation process involves excited states (thermally activated mechanism) without quantum tunnelling of magnetization (QTM) between the ground state Kramers doublets ( Figure S5).…”

Dysprosium Single-Molecule Magnets Involving 1,10-Phenantroline-5,6-dione Ligand

“…For a clearer representation of the potential, the intensity can be directly related to both the color (red = high potential and blue = low potential) and the height of the irregularities. This program has already been used in previous works to give some hints on the orientation of magnetization axes [79,80].…”

N3O6 versus N2O6 coordinated dysprosium slow magnetic relaxation in a tetrathiafulvalene-based dinuclear complex

“…[10c] [35] [42] The computation of the relaxation barriers for each non-equivalent center tends to highlight a thermally-assisted QTM mechanism occurring through the third excited state and leading to a calculated energy barrier of 207 cm -1 for Dy1 (Fig. S6).…”