Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (14): 1555-1560.DOI: 10.6023/A12030020 Previous Articles     Next Articles

Full Papers

Keggin型有机硅取代的多金属氧酸盐衍生物[XW11O40(SiR)2]n-(X=CoIII, P; R=CH=CH2, OH)的合成和表征

张建平a, 杨春a, 周家宏b   

  1. a 江苏省生物功能材料重点实验室 南京师范大学化学与材料科学学院 南京 210097;
    b 江苏省生物功能材料重点实验室 南京师范大学分析测试中心 南京 210097
  • 投稿日期:2012-03-23 发布日期:2012-05-03
  • 通讯作者: 杨春
  • 基金资助:

    项目受国家自然科学基金(No. 20473037);江苏高校优势学科建设工程和南京师范大学“211工程”三期重点学科建设计划资助.

Synthesis and Characterization of Organosilyl Derivatives of Keggin Polyoxometalates [XW11O40(SiR)2]n-(X=CoIII, P; R=CH=CH2, OH)

Zhang Jianpinga, Yang Chuna, Zhou Jiahongb   

  1. a Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Material Science, Nanjing Normal University, Nanjing 210097;
    b Jiangsu Key Laboratory of Biofunctional Materials, Analysis and Testing Center of Nanjing Normal University, Nanjing 210097
  • Received:2012-03-23 Published:2012-05-03
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 20473037), the Priority Academic Program Development of Jiangsu Higher Education Institutions and the Leading Academic Discipline Program of 211 Project of Nanjing Normal University (the 3rd phase).

The Keggin-type organosilyl substituted tungstocobaltates [CoIIIW11O40(SiR)2]5- (CoIIIW11(SiR)2, R=CH=CH2,OH) were synthesized for the first time by using CoIIIW11 and organosilane as starting materials. The syntheses were carried out in an ethanol-water mixing solvent with volume ratio of 2:1 and pH 1. Ethanol was employed as a cosolvent here to increase the solubility of organosilane in the reactive system, so that the organosilane was accessible and could react with CoIIIW11 before it was converted to CoIIIW12. The mixture was stirred at room temperature for 20 h, and then the product was obtained as tetramethylammonium (TMA) salt precipitate by adding tetramethylammonium chloride (TMACl). The structure and composition of the products were characterized by IR, UV-Vis, NMR, TG-DTA and elemental analysis techniques. The IR spectra showed that the Keggin units in the products were close to the saturated structure. Two SiR groups were inserted into the vacancy of CoIIIW11 and a Si—O—Si bridge was formed between two Si atoms, similar to those reported previously in organosilyl substituted tungstosilicate and tungstophosphate. This insertion of SiR groups was also confirmed by 29Si, 1H and 13C NMR of the products, but the 29Si signal exhibited a large chemical shift compared with those of organosilyl substituted tungstosilicate and tungstophosphate possibly due to the paramagnetism of CoIII. UV-Vis spectra of the products also indicated the conversion of the structural symmetry and the retainment of CoIII in the synthesis. The decomposing processes of the products were suggested by TG-DTA curves, which also revealed that, the anion in CoIIIW11(SiOH)2 possesses a higer stability than that in CoIIIW11 (SiCH=CH2)2. Furthermore, [PW11O40(SiR)2]3- [PW11(SiR)2, R=CH=CH2, OH], which were synthesized previously by the procedure of solid-liquid phase transfer, were also synthesized under the same conditions, indicating this method is a feasible and general approach for the synthesis of organosilyl substituted polyoxometalates.

Key words: tungstocobaltates, tungstophosphate, organosilyl substituted, Keggin structure, synthesis and characterization