Study On New Homogeneous And Heterogeneous Ruthenium Catalysts For Olefin Metathesis

The olefin metathesis reaction is the most powerful means to construct carbon-carbon double bonds,and is currently widely used in the fields of medicine,pesticides,and fine chemicals.In the catalytic olefin metathesis reaction system,the homogeneous catalyst with metal ruthenium as the catalytic active center can effectively catalyze the efficient progress of the olefin metathesis reaction.However,since the homogeneous ruthenium catalyst is difficult to be completely separated from the reaction system after the catalytic reaction is completed,it will inevitably cause the pollution of the target product.This research aims to improve its catalytic activity and reusability in catalyzing olefin metathesis reactions by preparing a new homogeneous and heterogeneous ruthenium catalyst.In this study,a new homogeneous ruthenium catalyst was constructed by synthesizing imidazole and pyridine carboxylate silver ionic liquids containing different anions and making them interact with the halogen ligands in the Grubbs Hoveyda second-generation catalyst(H-G 2^nd).At the same time,a novel heterogeneous ruthenium catalyst supported on magnetic nanoparticles（MNP）was synthesized using L-valin containing a chiral center as the starting material.In this study,we successfully constructed new homogeneous ruthenium catalysts2-12a,2-12b and 2-12c by modifying the H-G 2^nd halogen ligand.The above homogeneous ruthenium catalyst and H-G 2^nd were used to test the catalytic activity in cross metathesis（CM）and ring closing metathesis（RCM）reactions,it is found that the new homogeneous ruthenium catalyst 2-12b has higher catalytic activity.In this study,a new type of heterogeneous ruthenium catalyst 3-24 was successfully constructed using cheap and easily available L-valin as raw material.The determination by inductively coupled plasma massspectrometry（ICP-MS）showed that the amount of metal ruthenium supported on the MNP in the catalyst is 0.268 mmol/g.Heterogeneous ruthenium catalysts 3-24 and H-G 2^nd were used to test the catalytic activity in the asymmetric ring-closure cross olefin metathesis（ARCM）reaction and the asymmetric ring opening cross olefin metathesis（AROCM）reaction.The results show that the heterogeneous ruthenium catalyst 3-24 has high catalytic activity;when the heterogeneous ruthenium catalyst 3-24 catalyzes the ARCM reaction,the ee value is 36%,the yield is 93%,and it is produced after being recycled for 8 times.When catalyzing the AROCM reaction,the ee value can reach up to 59%,the yield can reach up to 83%,and the yield begins to decrease after 13 times of recycling,and it has good reusability.In this study,a heterogeneous ruthenium catalyst 3-24 was used to catalyze the cross-olefin metathesis reaction.The compound 3-26 was constructed to have 63.9%inhibitory rate against fusarium graminearum among the tested fungi,with an EC₅₀value of59.3μg/m L.It shows that compound 3-26 has good antibacterial activity against fusarium graminearum.