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Acta Chimica Sinica ›› 2008, Vol. 66 ›› Issue (2): 205-210. Previous Articles     Next Articles

Original Articles

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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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