一例基于Keggin型多酸阴离子的双加帽杂多铌酸盐的合成、结构及表征

摘要

在水热条件下,成功合成了一例基于Keggin型多酸阴离子的双加帽杂多铌酸盐[Ni(en)3]3[Ni(en)2(H2O)2]2H[VNb12O40(VO)2]·10H2O(1),并通过红外光谱、热重分析和X射线单晶衍射等方法对该化合物进行了表征.X射线单晶衍射分析表明,化合物1属于正交晶系,Pna2(1)空间群,晶胞参数a=3.0517(3)nm,b=1.5610(1)nm,c=2.2719(3)nm,V=10.823(3)nm3.化合物1包含1个Keggin型聚阴离子[VNb12O40(VO)2]11-和3个镍配离子.在阴离子结构中,中心钒原子被12个铌原子包围形成经典Keggin型结构的[VNb12 O40]15-阴离子,另外两个{VO}基团分别加帽于[VNb12 O40]15-阴离子的两端.%A new Keggin heteropolyoxoniobate [Ni(en)3]3[Ni(en)2(H2O)2]2H[VNb12O40(VO)2] ·10H2O (1) has been synthesized by hydrothermal method, and was characterized by IR spectrum, thermogravimetric ( TG) analysis and X-rays diffraction. X-ray structural analysis indicates that com-pound 1 crystallizes in the orthorhombic Pna2(1) space group with the cell constants:a = 3.0517(3) nm, b = 1.5610(1) nm, c = 2.2719(3) nm, V = 10.823(3) nm3. Compound 1 consists of a bi-capped Keggin polyanion [ VNb12 O40( VO) 2 ] 11-and three nickel-complexes as the countercations. The polyanion can be described as a decorated Keggin cluster with one vanadium atom as the central het-eroatom surrounded by twelve niobium atoms along with two {VO} groups capping two opposite sides.