Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), Department of Chemistry, Northwest University, Xìan, 710069, China.
Inorg Chem. 2012 Feb 20;51(4):2318-24. doi: 10.1021/ic202314g. Epub 2012 Feb 6.
A double sandwich polyoxometalate and its Fe(III) substituted derivative, As(2)Fe(5)Mo(21)O(82) (1) and As(2)Fe(6)Mo(20)O(80)(H(2)O)(2) (2), were synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy, fluorescent spectroscopy, UV spectra, thermogravimetry-differential scanning calorimetry analyses, electrospray ionization mass spectrometry, and magnetism measurements. The polyoxoanion is composed of a central fragment FeMo(7)O(28) for 1 (Fe(2)Mo(6)O(26)(H(2)O)(2) for 2) and two external AsMo(7)O(27) fragments linked together by two distinct edge-sharing dimeric clusters Fe(2)O(10) to lead to a C(2v) molecular symmetry. The central FeMo(7)O(28) fragment and external AsMo(7)O(27) fragment have a similar structure, and both of them can be viewed as a monocapped hexavacant α-Keggin subunit with a central FeO(4) group or a central AsO(3) group. Both of the polyoxoanions contain a oxo-bridged Fe(III)(5) magnetic core with the angles of Fe-O-Fe in the range of 96.4(4)-125.7(5)°, and magnetism measurements show an overall ferromagnetic interactions among the five-nuclearity cluster Fe(5) with the spin ground state S = 15/2.
一种夹心型多金属氧酸盐及其 Fe(III)取代衍生物，As(2)Fe(5)Mo(21)O(82) (1) 和 As(2)Fe(6)Mo(20)O(80)(H(2)O)(2) (2)，通过单晶 X 射线衍射、红外光谱、荧光光谱、紫外光谱、热重-差示扫描量热分析、电喷雾电离质谱和磁化率测量进行了合成和表征。多阴离子由一个中心片段 FeMo(7)O(28)组成（Fe(2)Mo(6)O(26)(H(2)O)(2) 为 2）和两个外部 AsMo(7)O(27)片段通过两个不同的边共享二聚体簇 Fe(2)O(10)连接在一起，导致 C(2v)分子对称性。中心 FeMo(7)O(28)片段和外部 AsMo(7)O(27)片段具有相似的结构，它们都可以看作是一个单核六缺位的α-Keggin 亚基，具有中心 FeO(4)基团或中心 AsO(3)基团。两个多阴离子都含有一个氧桥联的 Fe(III)(5)磁核，Fe-O-Fe 角在 96.4(4)-125.7(5)°范围内，磁化率测量表明五核簇 Fe(5)之间存在整体铁磁性相互作用，基态自旋 S = 15/2。
