| Polyoxometalates（POMs）have attracted much attention because of their structural tunable flexibility and they have been widely used in the fields of battery,energy,medicine,catalysis,and sensing.In this paper,nine POMs compounds were successfully synthesized using V2O5,Na2WO4,Cu（NO3）2,Ag NO3,etc.as inorganic materials,imidazole and pyrimidine derivatives as organic ligands by adjusting the p H values of the reaction system.These POMs compounds were fully characterized by single-crystal X-ray diffraction（SCXRD）,powder X-ray diffraction（PXRD）and fourier transform infrared spectroscopy（FTIR）,and were discussed its catalysis in detail.1.Three imidazole-modified polyoxovanadates were synthesized by under routine conditions:[Co（1-ip IM）（H2O）5]2(H2V10O28)·6H2O（1）,[Ni（1-ip IM）（H2O）5]2(H2V10O28)·6H2O（2）,and[Ag（1-e IM）2]2[Ag2（1-e IM）4]2[H3V10O28]2·2（1-e IM）·2H2O（3）（1-ip IM=1-isopropylimidazole;1-e IM=1-ethylimidazole）.The catalytic performance of compounds 1-3 were studied in sulfides oxidation and Mannich reaction,especially compound 3 showed excellent heterogeneous bifunctional catalytic performance in the selective oxidation of sulfides and the construction of C-C bonds.Moreover,the catalyst maintained catalytic activities unchanged and structural stability after three cycles.2.Three imidazole-modified polyoxometalates were synthesized by under hydrothermalsynthesis:Cu（1-ip IM4）2(V2W4O19)·8H2O（4）,Cu（1-ip IM2）{[Cu（1-ip IM2）2](VW5O19)}（5）,[Cu（1-e IM）4]3(HV2W4O19)2·2（1-e IM）（6）.Compounds 4-6 were used to catalyze the cyclization reaction of propargyl alcohol and carbon dioxide,the results proved that compound 6 had the best catalytic effect.Corresponding substrates expansion were carried out under the best reaction conditions,and it was found that cyclization reaction of different substituted propargyl alcohols and CO2,the yields are up to 90%.3.Three pyrimidine-modified polyoxometalates,were synthesized by hydrothermal synthesis,Cu2（L1）2(PW12O40)·4H2O（7）,[Cu（L1）（H2O）2]2(HPMo10V2O40)（8）[Cu（L2）（H2O）]2(PW12O40)·2H2O（9）（L1=4-（pyridin-2-yl）-6-（pyridin-4-yl）pyrimidin-2-amine,L2=4-（pyridin-2-yl）-6-（4-（pyridin-4-yl）phenyl）pyrimidin-2-amine）.Compounds 7-8 were investigated as catalysts in phenylacetylene-dichloromethane-diethylamine coupling,the results proved that compound 7 had the best catalytic effect.Corresponding substrates expansion were carried out under the best reaction conditions,and it was found that reaction of different substituted phenylacetylene-dichloromethane-diethylamine coupling,the yields are up to 80%. |
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