Slow Magnetic Relaxation in a Palladium–Gadolinium Complex Induced by Electron Density Donation from the Palladium Ion

Abstract

Incorporating palladium in the first coordination sphere of acetato-bridged lanthanoid complexes, [Pd Ln (H O) (AcO) ]⋅2 AcOH (Ln=Gd (1), Y (2), Gd Y (3), Eu (4)), led to significant bonding interactions between the palladium and the lanthanoid ions, which were demonstrated by experimental and theoretical methods. We found that electron density was donated from the d Pd ion to Gd ion in 1 and 3, leading to the observed slow magnetic relaxation by using local orbital locator (LOL) and X-ray absorption near-edge structure (XANES) analysis. Field-induced dual slow magnetic relaxation was observed for 1 up to 20 K. Complex 3 and frozen aqueous and acetonitrile solutions of 1 showed only one relaxation peak, which confirms the role of intermolecular dipolar interactions in slowing the magnetic relaxation of 1. The slow magnetic relaxation occurred through a combination of Orbach and Direct processes with the highest pre-exponential factor (τ =0.06 s) reported so far for a gadolinium complex exhibiting slow magnetic relaxation. The results revealed that transition metal-lanthanoid (TM-Ln) axial interactions indeed could lead to new physical properties by affecting both the electronic and magnetic states of the compounds.

Importance of Axial Symmetry in Elucidating Lanthanide–Transition Metal Interactions

“…Our conclusion agrees with a recently reported localized orbital bonding simulation performed on a La-Pd and La-Pt complexes with similar ligands. 22,25 The set of CF parameters that we extracted allowed the excellent simulation of the static magnetic properties (χT and magnetization curves, Figure S21-S22). For all the complexes, the χT curves approach the Curie constant at around 100 K, testifying to the relatively small splitting of the ground multiplet compared to the thermal energy at room temperature.…”

Slow magnetic relaxation in Ni–Ln (Ln = Ce, Gd, Dy) dinuclear complexes

“…Two slow relaxation processes have also been described for several Gd(III) compounds. 20,22,23,28,29 For instance, for a Gd(III)EDTA chelate compound, 29 the values of U eff = 6.1 K (τ = 4 × 10 −2 s) and U eff = 84 K (τ = 8 × 10 −7 s) were reported (B DC = 0.45 T). The geometry and the electron density of the coordination sites has been proved to exert a very important influence on the SMM behaviour of lanthanide ions.…”

“…Despite its essentially isotropic ground state with L = 0, several materials have been reported for which magnetic anisotropy around the gadolinium(III) centre was induced by local coordination, magnetic exchange coupling or electron density donation. [20][21][22][23][24][25][26][27][28][29] These materials containing gadolinium(III) may be considered as members of a new class of SMMs with the highest known spin state (4f 7 ) for a single ion.…”

David Brown Award: S. Draper / Wiley–CST Green Chemistry Award: C. Wattanakit / Gottfried‐Wilhelm‐Leibniz‐Preis: W. Wernsdorfer

“…Seiner Forschergruppe gelang es, die Quanten‐Spin‐Zustände in einem Molekül zu messen und zu kontrollieren und dadurch einfache Quantenalgorithmen zu implementieren. Er berichtete in einer Angewandte ‐ Chemie ‐Zuschrift über dysprosiumbasierte Kernspinisomere, und er war Koautor einer Zuschrift über die langsame magnetische Relaxation in einem Palladium‐Gadolinium‐Komplex, die als Titelbildbeitrag in Chemistry—A European Journal vorgestellt wurde …”