Novel 3D Alkali鈥揕anthanide Heterometal鈥揙rganic Frameworks with Pyrazine-2,3,5,6-tetracarboxylic Acid: Synthesis, Structure, and Magnetism

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• 作者：Fengming Zhang ; Pengfei Yan ; Xiaoyan Zou ; Juwen Zhang ; Guangfeng Hou ; Guangming Li
• 刊名：Crystal Growth & Design
• 出版年：2014
• 出版时间：April 2, 2014
• 年：2014
• 卷：14
• 期：4
• 页码：2014-2021
• 全文大小：540K
• 年卷期：v.14,no.4(April 2, 2014)
• ISSN：1528-7505

文摘

Three novel alkali鈥搇anthanide heterometal鈥搊rganic frameworks, namely, [K₅Ln₅(pztc)₅(H₂O)₁₉]路7H₂O [Ln = Dy (1), Ho (2), and Yb (3); H₄pztc = pyrazine-2,3,5,6-tetracarboxylic acid], have been facilely synthesized. X-ray crystallographic analysis reveals that complexes 1鈥?b>3 are isostructural, featuring unique 3D open frameworks, which possess a rare (4,8)-connected net with the Schl盲fli symbol of (4¹⁵路6¹²路8)(4⁵路6)₂. The 3D coordination framework involves a ladder-like square column structure by pztc^{4鈥?/sup> ligands bridging metal ions, exhibiting 1D channels along the b axis. The magnetic analysis suggests that complexes 1 and 3 exhibit frequency-dependent out-of-phase signals in alternating current magnetic susceptibility measurements, indicating their slow magnetic relaxation characteristics. It is the first report of slow magnetic relaxation behavior existing in Yb3+-based HMOFs.}