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化学学报
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化学学报 ›› 2008, Vol. 66 ›› Issue (2): 205-210. 上一篇    下一篇

研究论文

一个新的夹心型杂多钨酸盐Na6(C5N2H7){[Na(H2O)2]3Co(H2O)5-[Co(H2O)]3(AsW9O33)2}•27H2O的晶体结构及性质

尚军飞1，任淑华2，甄延忠2，付峰*,1，王继武1，薛岗林*,1,2   

  1. (1延安大学 陕西省化学反应工程重点实验室 延安 716000)
    (2西北大学化学系 陕西省物理无机化学重点实验室 西安 710069)
  • 投稿日期:2006-12-05 修回日期:2007-05-22 发布日期:2008-01-28
  • 通讯作者: 薛岗林

Crystal Structure and Properties of a New Sandwich Heteropolytungstate Na6(C5N2H7){[Na(H2O)2]3- Co(H2O)5[Co(H2O)]3(AsW9O

SHANG Jun-Fei1 REN Shu-Hua2 ZHEN Yan-Zhong2 FU Feng*,1 WANG Ji-Wu1 XUE Gang-Lin*,1,2   

  1. (1 Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan'an University, Yan'an 716000)
    (2 Shaanxi Key Laboratory of Physico-inorganic Chemistry, Department of Chemistry, Northwest University, Xi'an 710069)
  • Received:2006-12-05 Revised:2007-05-22 Published:2008-01-28
  • Contact: XUE Gang-Lin

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在pH＝7.5的水溶液中, Na2WO4•2H2O, NaAsO2, CoCl2•6H2O与对氨基吡啶反应, 得到了一种新的夹心型杂多钨酸盐Na6(C5H7N2){[Na(H2O)2]3Co(H2O)5[Co(H2O)]3(AsW9O33)2}•27H2O单晶, 用X射线单晶衍射法及元素分析确定了其结构, 晶体属三斜晶系, P 空间群, 其晶胞参数为: a＝1.3276(8) nm, b＝1.7581(10) nm, c＝2.4381(14) nm, α＝70.954(9)°, β＝86.663(9)°, γ＝72.885(9)°, V＝5.136(5) nm3, Z＝2, R1＝0.0608, wR2＝0.0848 [I＞2σ(I)]. 在{[Na(H2O)2]3Co(H2O)5[Co(H2O)]3(AsW9O33)2}7－阴离子中, 一个Co2＋与聚阴离子{[Na(H2O)2]3[Co(H2O)]3(AsW9O33)2}9－的一个端基氧共价连接, Co2＋呈现出5和6两种配位数, 质子化的氨基吡啶正离子作为抗衡离子存在于晶体之中. 对标题化合物进行了IR, UV-Vis, TG-DSC表征. 对该化合物、Na2WO4•2H2O及CoCl2•6H2O催化H2O2氧化乙醛的活性进行了比较研究, 该化合物的催化活性远优于简单化合物Na2WO4•2H2O和CoCl2•6H2O.

关键词: 杂多化合物, 晶体结构, 钴, 醛的氧化

A new sandwich heteropolytungstate Na6(C5N2H7){[Na(H2O)2]3Co(H2O)5[Co(H2O)]3- (AsW9O33)2}•27H2O was synthesized by the reaction of Na2WO4•2H2O, NaAsO2, CoCl2•6H2O and p-aminopyridine (C5H7N2) in pH＝7.5 aqueous solution. The single crystal X-ray diffraction study shows that the crystal belongs to triclinic system, space group P , with a＝1.3276(8) nm, b＝1.7581(10) nm, c＝2.4381(14) nm, α＝70.954(9)°, β＝86.663(9)°, γ＝72.885(9)°, V＝5.136(5) nm3，Z＝2, R1＝0.0608, wR2＝0.0848 [I＞2σ(I)]. The structure of anion {[Na(H2O)2]3Co(H2O)5[Co(H2O)]3(AsW9O33)2}7－ reveals a sandwich arrangement of two {α-B-AsW9} moieties enclosing three Co(H2O)2＋ and three , and another connects with one terminal oxygen of {[Na(H2O)2]3[Co(H2O)]3(AsW9O33)2}9－. There are two kinds of coordination numbers of Co2＋ in the polyanion, 5 and 6. The title compound was also characterized by IR, UV-Vis and TG-DSC. The formation condition of the the title compound was discussed. It was shown that the title compound was much more effective than Na2WO4•2H2O or CoCl2•6H2O for the catalytic oxidation of acetaldehyde with hydrogen peroxide in an aqueous solution.

Key words: polyoxometalate, crystal structure, cobalt, oxidation of aldehyde