Hydrothermal Syntheses and Structural Characterizations of Polyoxometalate (Mo/W) Compounds Consisting of M-L Cations, (M = Mn, Co, Ni, Cu, Zn; L = 3-(2-Pyridyl)pyrazole)
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- 作者：Xiutang Zhang ; Peihai Wei ; Daofeng Sun ; Zhonghai Ni ; Jianmin Dou ; Bin Li ; Congwen Shi ; Bo Hu
- 刊名：Crystal Growth & Design
- 出版年：2009
- 出版时间：October 7, 2009
- 年：2009
- 卷：9
- 期：10
- 页码：4424-4428
- 全文大小：742K
- 年卷期：v.9,no.10(October 7, 2009)
- ISSN：1528-7505
文摘
A series of molybdenum/tungsten polyoxometalate compounds, namely, [(MII(HL)2)Mo3O10] (M = Mn (1), Co (2), Ni (3)), [CuII2(L)2(HL)2]2(Mo8O26) (4), [Zn(HL)2(MoO4)]2·HL·4H2O (5), [CuII4(L)6WO4)]·3H2O (6) (HL = 3-(2-pyridyl)pyrazole), were designed and synthesized under hydrothermal conditions. X-ray diffraction analyses reveal that compounds 1−3 have an isostructural wavelike chain structure consisting of the asymmetric building blocks of [Mo3O10], in which the ratio of octahedron {MoO6} and square pyramid {MoO5} is 1:2. The hexacoordinated transitional metal cation, just like one “anchor” to fix the above wavelike chain, is linked by two terminal oxygen atoms belonging to two edged asymmetric molybdate [Mo3O10]2− units, and further chelated by two 3-(2-pyridyl)pyrazole ligands. Although a similar synthetic method in preparation of 1−5 was employed, compounds 4 and 5 show a completely different structure compared to compounds 1−3. Compound 4 is composed of two separate parts of the [CuII2(L)2(HL)2]2+ dimer and the ε-[Mo8O26]4− unit. Compound 5 consists of a bimetallic tetranuclear cluster that is constructed from corner-sharing {MoO4} tetrahedra and {ZnN4O2} distorted octahedron forming a cyclic {Zn2Mo2O4} core. For compound 6, a one-dimensional structure is composed of WO42− linked by the centrosymmetric tetranuclear copper grids, in which two approximately planar [CuII(L)]2 units with an inversion center stack parallel and face-to-face linked by two additional deprotonated ligands of L−1 perpendicularly.