Three Banana-Shaped Arsenomolybdates Encapsulating a Hexanuclear Transition-Metal Central Magnetic Cluster: [AsIII2FeIII5MMo22O85(H
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- 作者：Bin Liu ; Lili Li ; Yanping Zhang ; Ying Ma ; Huaiming Hu ; Ganglin Xue
- 刊名：Inorganic Chemistry
- 出版年：2011
- 出版时间：September 19, 2011
- 年：2011
- 卷：50
- 期：18
- 页码：9172-9177
- 全文大小：852K
- 年卷期：v.50,no.18(September 19, 2011)
- ISSN：1520-510X
文摘
Three polyoxometalates encapsulating high-nuclearity magnetic clusters MFe5, [As2MFe5Mo22O85(H2O)]n鈭?/sup> (M = Fe3+, n = 14; M = Ni2+ and Mn2+, n = 15), were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, thermogravimetric analysis, and magnetism measurements. The polyanion [As2MFe5Mo22O85(H2O)]n鈭?/sup> consists of a central MMo7O28 (M = Fe3+, Ni2+, and Mn2+) fragment and two AsMo7O27 fragments linked together by two trimeric clusters, Fe2MoO(渭2鈥揙)2 and Fe3(H2O), to form a banana-shaped structure with C1 symmetry. The MMo7O28 and AsMo7O27 units have a similar structure and can be considered as a monocapped hexavacant 伪-B-Keggin subunit with a central MO4 group or a central AsIIIO3 group. The polyoxometalates have a low absorption of 蠀(Mo鈥揙d) (925鈥?13 cm鈥?) because most of the Mo atoms in the polyanions have at least two longer Mo鈥揙d bonds. The framework of the arsenomolybdates is stable before As2O3 escaping (ca. 300 掳C). The analysis of magnetostructural correlations and magnetism measurements indicate the coexistence of ferro- and antiferromagnetic interactions, which give an overall ferromagnetic spin ground state in the compounds.