Li Xin-Xiong, Fang Wei-Hui, Zhao Jun-Wei, Yang Guo-Yu
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China), Fax:(+86) 591-83710051.
Chemistry. 2014 Dec 22;20(52):17324-32. doi: 10.1002/chem.201404384. Epub 2014 Nov 5.
Three novel hexa-Ni-substituted Dawson phosphortungstates [Ni6 (en)3 (H2O)6 (μ3-OH)3 (H3 P2 W15 O56 )]⋅14 H2O (1), [Ni(enMe)2 (H2O)][Ni6 (enMe)3 (μ3-OH)3 (H2O)6 (HP2 W15 O56)]⋅ 10 H2O (2), and [Ni(enMe)2 ]3 [Ni(enMe)2 (H2O)][Ni(enMe)(H2O)2][Ni6 (enMe)3 (μ3-OH)3 (Ac)2 (H2O)(P2 W15 O56)]2 ⋅6 H2O (3) (en=ethylenediamine, enMe=1, 2-diaminopropane, Ac=CH3 COO(-)) have been made under hydrothermal conditions and were characterized by IR spectroscopy, elemental analysis, diffuse reflectance spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. The common structural features of compounds 1-3 contain the similar hexa-Ni-substituted Dawson polyoxometalate (POM) units that can be viewed as a Ni6 (μ3-OH)3 cluster capping on a P2 W15 O56 fragment. Compounds 1 and 2 are two isolated clusters, whereas compound 3 is the first 3D POM framework constructed from hexa-Ni-substituted Dawson POM units and Ni(enMe) complex bridges. The preparations of compounds 1-3 not only indicate that triangle coplanar Ni6 clusters are very stable fragments in both trivacant Keggin and trivacant Dawson POM systems, but also offer that the hydrothermal technique can act as an effective strategy for making novel Dawson-type high-nuclear transition-metal cluster substituted POMs by combination of lacunary Dawson precusors with transition-metal cations in the tunable role of organic ligands. In addition, magnetic measurements illustrate that there exist overall ferromagnetic interactions in compound 3.
通过水热法合成了三种新型的六镍取代道森磷钨酸盐[Ni6 (en)3 (H2O)6 (μ3-OH)3 (H3 P2 W15 O56 )]⋅14 H2O (1)、[Ni(enMe)2 (H2O)][Ni6 (enMe)3 (μ3-OH)3 (H2O)6 (HP2 W15 O56)]⋅ 10 H2O (2)和[Ni(enMe)2 ]3 [Ni(enMe)2 (H2O)][Ni(enMe)(H2O)2][Ni6 (enMe)3 (μ3-OH)3 (Ac)2 (H2O)(P2 W15 O56)]2 ⋅6 H2O (3)（en = 乙二胺，enMe = 1,2 - 二氨基丙烷，Ac = CH3 COO(-)），并通过红外光谱、元素分析、漫反射光谱、热重分析、粉末X射线衍射和单晶X射线衍射对其进行了表征。化合物1 - 3的共同结构特征包括类似的六镍取代道森多金属氧酸盐（POM）单元，可视为Ni6 (μ3-OH)3簇覆盖在P2 W15 O56片段上。化合物1和2是两个孤立的簇，而化合物3是由六镍取代道森POM单元和Ni(enMe)络合物桥构建的第一个三维POM框架。化合物1 - 3的制备不仅表明三角形共面的Ni6簇在三缺位的Keggin和三缺位的道森POM体系中是非常稳定的片段，而且还表明水热技术可以作为一种有效的策略，通过将缺位道森前驱体与过渡金属阳离子在有机配体的可调作用下相结合来制备新型道森型高核过渡金属簇取代的POM。此外，磁性测量表明化合物3中存在整体铁磁相互作用。
