A Family of Double Cubanes {Cr(2)(III)Ln(4)(III)O(6)} (Ln = Tb, Ho, Er, Yb, Y) Based on Sulfate: Single-Molecule Magnet Behavior in the Terbium and Erbium Analogues

作者：Xiang, Hua; Lu, Wen-Guan^*; Jiang, Long; Zhang, Wei-Xiong; Lan, Yanhua^*

来源：European Journal of Inorganic Chemistry, 2016, 2016(6): 907-912.

DOI：10.1002/ejic.201501285

• Chromium
• Cluster compounds
• Magnetic properties
• Lanthanides
• Hydrothermal synthesis

The synthesis and characterization of a family of compounds (pipzH(2))[Cr(2)(III)Ln(4)(III)(mu(4)-O)(2)(mu(3)-OH)(4)(H2O)(10)(mu(3)-SO4)(4)(SO4)(2)]2H(2)O [hereafter abbreviated as Cr(2)Ln(4); Ln = Tb (1), Ho (2), Er (3), Yb (4), and Y (5); pipz = piperazine] are reported. The compounds were obtained from hydrothermal reactions of Ln(NO3)(3)6H(2)O (Ln = Tb, Ho, Er, Yb, and Y), Cr(NO3)(3)9H(2)O, Na2SO4, and pipz in a 2:1:3:4 molar ratio. Single-crystal X-ray diffraction studies revealed that 1-5 crystallize isomorphously in the space group P2(1)/c with Z = 2. The metallic core is composed of a rare face-fused double-cubane [Cr(2)(III)Ln(4)(III)(mu(4)-O2-)(2)(mu(3)-OH-)(4)](10+) unit. The temperature dependence of bulk magnetic susceptibilities is indicative of antiferromagnetic interactions dominant in the Tb, Ho, and Er compounds. In fitting with the data of the diamagnetic Y-III analogue, the interactions of Cr-Cr in this system are determined to be ferromagnetic with a coupling strength of 3.61(11) cm(-1), but the type of Cr-Ln could be antiferromagnetic. The dynamic magnetic properties revealed the presence of slow magnetic relaxation in the Tb and Er analogues, which represent two rare examples of Cr-III-containing clusters that exhibit single-molecule magnet (SMM) behavior.

• 出版日期2016-2
• 单位韶关学院; 中山大学