Switching the anisotropy barrier of a single-ion magnet by symmetry change from quasi-D5h to quasi-Oh

Abstract

A reversible single-crystal-to-single-crystal transformation is used to dramatically change the relaxation behavior of a single-ion magnet. The coordination geometry of the Dy III site of a [Zn-Dy-Zn] complex changes from pentagonal-bipyramid (quasi-D 5h ) to octahedron (quasi-O h ), inducing an energy barrier change from 305 cm À1 (439 K) to a negligible value, respectively. Ab initio calculations reveal that the ideal D 5h -Dy III is of perfect axiality with a substantial energy barrier in accordance with the experimental result.

An electrostatic model for the determination of magnetic anisotropy in dysprosium complexes

“…Compounds 12 and 13, chosen as a departure from bdiketonate-based complexes in addition to their very interesting magnetic properties, are intimately related and can be interconverted reversibly by drying or soaking in methanol, via a single crystal to single crystal transformation 7 . The difference between the dysprosium(III) coordination environments is the removal of a terminal methanol molecule, changing the local symmetry from a distorted pentagonal bipyramid to a distorted octahedron.…”

“…The pursuit of such applications relies on detailed knowledge of the magnetic anisotropy, which, while being completely defined in cases of high symmetry, is difficult to elucidate in low-symmetry complexes. Much recent work, where 4f complexes have shown slow magnetic relaxation [4][5][6][7] and unprecedented non-collinear magnetic textures at the single-molecule level [8][9][10] , also depends on understanding the orientation of the magnetic anisotropy. Of all the lanthanide ions, it is Dy III that continues to prove the most interesting, providing unexpected examples of new magnetic phenomena, by virtue of its unique magnetic anisotropy 11 .…”

Theoretical Understanding of Anisotropy in Molecular Nanomagnets

“…6a) and polyoxometalates [19], having a D 4d symmetry in the absence of distortions (ideal geometry), only the parameters B (18) and can be determined from magnetic data. Recently, an ab initio methodology of calculation of crystal-field parameters for lanthanides has been proposed [84,85] and implemented [83] in the module SINGLE_ANISO of MOLCAS package [62]. As an example, Fig.…”

Photo-Modulation of Single-Molecule Magnetic Dynamics of a Dysprosium Dinuclear Complex via a Diarylethene Bridge

“…The 2 close crystallized in the triclinic P1 space group. The asymmetric unit is composed of two Dy(hfac) 3 bridged by a DTE ligand and one heptane molecule as crystal solvent ( Figure 3). Each Dy ion was crystallographically independent and was coordinated by two nitrogen atoms from the bipyridine group and six oxygen atoms from three hfac − moieties.…”