0000000000485228
AUTHOR
A. Alhassanat
Element-specific magnetic properties of mixed 3d−4f metallacrowns
Single molecule magnets comprising rare earth metals are of high interest due to the unquenched orbital moments of the rare earth ions that result in a large energy barrier for magnetization reversal. We investigate the magnetic properties of polynuclear $3d\text{\ensuremath{-}}4f15$-MC-5 metallacrowns using x-ray magnetic circular dichroism of powder samples at a temperature of 7 K in a magnetic field of 7 T. The sum rule analysis reveals element-specific spin and orbital moments. The magnetic moments of the $3d$ transition metal Ni(II) ions are coupled antiferromagnetically to each other and contribute only little to the total molecular moment. The spin and orbital moments of the rare ear…
Solvent-induced high-spin transition in double-decker 3d–4f metallacrowns
Element-specific magnetic spin and orbital magnetic moments of $3d\text{\ensuremath{-}}4f$ double-decker metallacrown molecules have been investigated using x-ray magnetic circular dichroism. The double-decker metallacrowns comprise one rare-earth Gd(III) or Tb(III) ion embedded between two squared scaffolds of four Ni(II) ions. We observe a strong increase of the Ni(II) moments if the molecules are dissolved in methanol, indicating a spin crossover from a low-spin to a high-spin state. In contrast, dichloromethane does not change the spin state. This result is explained by a change of the coordination environment of nickel. The comparison of charge-transfer multiplet calculations with the …