Crystal Structure and Magnetic Properties of Peacock–Weakley Type Polyoxometalates Na<sub>9</sub>[Ln(W<sub>5</sub>O<sub>18</sub>)<sub>2</sub>] (Ln = Tm, Yb): Rare Example of Tm(III) SMM
oleh: Oleksandra Yu. Mariichak, Sandra Kaabel, Yevgen A. Karpichev, Georgiy M. Rozantsev, Serhii V. Radio, Céline Pichon, Hélène Bolvin, Jean-Pascal Sutter
| Format: | Article |
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| Diterbitkan: | MDPI AG 2020-10-01 |
Deskripsi
We report Peacock–Weakley complexes, Na<sub>9</sub>[Ln(W<sub>5</sub>O<sub>18</sub>)<sub>2</sub>]∙35H<sub>2</sub>O, formed with Tm(III), <b>1</b>, and Yb(III), <b>2</b>. Their syntheses, physico-chemical characterizations, crystal structures, and magnetic properties are described. Ab initio calculations are also reported. These polyoxometalate (POM) complexes were obtained using original synthetic conditions where acidification was performed with a stoichiometric amount of nitric acid to an acidity of <i>Z</i> = <i>ν</i>(H<sup>+</sup>)/<i>ν</i>(WO<sub>4</sub><sup>2–</sup>) = 8/10 = 0.80. Both the Tm(III) and Yb(III) derivatives were found to exhibit field-induced slow relaxation of their magnetization likely controlled by Raman and Orbach relaxation processes. <b>1</b> is a rare example of a Tm(III)-based single-molecule magnet (SMM) and is a consequence of the oblate tetragonal anti-prismatic symmetry of the coordination sphere.