Synthesis Of Polyoxovanadates And Polyoxomolybdates Decorated By Imidazole Derivates And Study On Their Catalytic Property

Polyoxometalates（POMs）have been paid inten-sive attention in recent years because of their extensive applications in catalysis,sorption,electrical conductivity,magnetism,medicine and materials science.Polyoxovanadates（POVs）and polyoxomolybdates（POMos）are important branches in the POMs family.In this thesis,15 compounds were synthesized successfully.These compounds were characterized by X-ray diffraction（SCXRD）,powder diffraction（PXRD）and infrared spectroscopy（IR）.The specific works are as follows:1.Four imidazole-modified Ag-POVs compounds were synthesized by under routine conditions: [Ag（N-Im）₂]₄[V₄O₁₂]（1）,[Ag（1-m Im）₂]₁₀(H₂V₁₀O₂₈)₂[Na（1-m Im）]2(V₄O₁₂)（2）,[Ag（1-e Im）₂]₉(HV₁₀O₂₈)₂(H₂V₁₀O₂₈)（3）,[Ag（1-p Im）₂]₅(HV₁₀O₂₈)（4）.These compounds were characterized by SCXRD,PXRD,IR,etc.Notably,compared with compounds 2,3,4,compound 1 as effective heterogeneous catalysts showed higher catalytic activities for Mannich reaction,yield up to 99%.Moreover,the catalyst was recycled and reused up to three runs without any significant loss of its catalytic activity.2.Five imidazole-modified Ni-POVs compounds were synthesized by under routine conditions: [Ni（1-m Im）₄（H₂O）₂][Ni（H₂O）₅]2(V₁₀O₂₈)·4H₂O（5）,[Ni（1-eIm）（H₂O）₄]2(H₂V₁₀O₂₈)（1-eIm）₂·2H₂O（6）,[Ni（H₂O）5]2(H₂V₁₀O₂₈)（1-pIm）₂（7）,[Ni（H₂O）₅]₂(H₂V₁₀O₂₈)（1-ipIm）₂·6H₂O（8）,[Ni（1-bIm）₄]2(V₄O₁₂)·H₂O（9）.These compounds were characterized by These compounds were characterized by SCXRD,PXRD,IR,etc.And these compounds 5-9 showed efficient catalytic activities for Knoevenagel condensation under slovent-free conditions.The results showed that the catalytic effect of compound 9 was the best,the yield was up to 99%.In addition,other benzaldehyde derivatives were further selected as reaction substrates,in order to evaluate the scope and limitations of the current procedure.Notably,the catalyst was recycled and reused up to three runs without any significant loss of its catalytic activity.3.Six midazole-modified Cu-POMs compounds were synthesized by hydrothermal synthesis,three of which were imidazole-modified copper-molybdenum oxygen cluster compounds: Cu（1-mIm）₆Cl₂·2H₂O（10）,[Cu（1-eIm）₄（Mo₂O₇）（11）,Cu（1-pIm）₆Cl₂（12）,Cu（1-ipIm）₆Cl₂（13）,Cu（1-ipIm）₄Mo₄O₁₃（14）,[Cu（1-bIm）₄]Mo₄O₁₃（15）,these compounds were characterized by These compounds were characterized by SCXRD,PXRD,IR,etc.And compounds 10-15 were investigated as a heterogeneous catalyst in the oxidationof of diphenylmethane and thioether oxidation,the results indicated that compounds 15 possesses higher conversion and remarkable yield than other compounds（the yield can reach 99%）,and the corresponding substrates expansion were carried out.Additionally,compounds 15 exhibits good stability and excellent recyclability after three runs.