The Study Of Catalysis Of Polyoxometalate-based Carbonyl Metal Derivatives

Polyoxometalates（POMs）not only possess various structures,but also have a number of characteristics,such as adjustable acidities and redox properties,so they are usually used as multifunction catalysts,and played a vital role in the catalytic field.In addition,the structures of POMs are clear,and can be modified by changing elements’species and the ratios of raw materials,therefore we can obtain a serious of specialized catalysts.In addition,metal carbonyl compounds also exhibited excellent catalytic performances in many organic reactions.As a peculiar branch of POMs,POM-based metal carbonyl derivatives not only has characteristics of metal carbonyl compounds,but also have characteristics of POMs,considerable attention has been directed toward POM-based metal carbonyl derivatives because of their unique structures and potential catalytic properties.In this paper,detailed studies on sulfoxidation reaction、epoxidation of olefins、and CO₂ cycloaddition by using various POM-based metal carbonyl derivatives have been carefully conducted,and the specific contents are as follows:1.[（CH₃）₄N]₄[{Re（CO）₃}₄(Mo₄O₁₆)]·H₂O（1）,[N（CH₃）₄]₆H₄[P₂W₁₇O₆₂Re₂（CO）₆]·25H₂O（2）and [N（CH₃）₄]₉H₃[As₂W₂₀O₇₁（H₂O）₂（Re（CO）₃）₄]·16H₂O（3）were selected to be catalysts,and the sulfoxidation reactions were studied systematically with using H₂O₂ as a green oxidant.The results show that they are all homogeneous catalysts,and the catalytic reactions all follow pseudo-first-order kinetics.Compound 1exhibited particularly excellent catalytic activity,and sulfoxides or sulphones can be obtained by controlling different experimental conditions.2.Na₂H₂[（CH₃）₄N]₆[Te₂W₂₀O₇₀{Re（CO）₃}₂]·20H₂O（4）was selected to be a catalyst,and the epoxidation of olefins was studied systematically.The results show that compound 4 exhibited excellent heterogeneous catalytic performance,and the substrate can be totally oxidated with high selectivity at75°C within 0.5 h.In the reaction of oxidation of olefins,catalyst testing was extended to explore their performance across various olefins,including different cycloalkenes,styrene derivatives,internal and long-chain alkenes.3.Na_1.5H_4.5[（CH₃）₄N]₂[{Mn（CO）₃}₄(Se₂W₁₁O₄₃)]·9H₂O（5）,and[Na（H₂O）₅]（NH₄）₇[P₂W₁₅O₅₆Co₃（H₂O）₃（μ₃-OH）₃Re（CO）₃]·6H₂O（6）were selected to be catalysts,and the CO₂ cycloaddition reactions were studied systematically in conjunction with 1-ethyl-1-methylpyrrolidinium bromide.The experimental results show that the two catalysts both showed excellent heterogeneous catalytic performance for CO₂ cycloaddition reaction,and the catalyst systems composed of POMs and ionic liquid were mild and have high catalytic activities.