Cu-Ag Bimetallic Nanoparticles Catalyzed Coupling Reaction Of Alkynes To Aldehydes&the Cascade Synthesis Of 3-alkylphthalides

In this thesis, copper-silver bimetallic nanoparticles were prepared and utilized as catalyst in the coupling reaction of terminal alkynes to aldehydes and the three-step cascade synthesis of 3-alkyl phthalides derives.In reccent years, much attention has been attracted to the use of nanoparticles as catalysts in organic reactions. Because of their easy preparation and relative stabilities in air, the nanoparticles of IB metals, such as copper, silver and gold, were widely reported, and there are many excellent examples on their applications as catalysts in organic reactions.On the other hand, as a powerful strategy to improve the synthetic efficiency, the bimetallic co-catalyst has attracted much attention.In this thesis, copper-silver bimetallic nanoparticles were prepared by using liquid-phase reduction with Cu(NO3)2 and AgNO3 as precusors, and then, were characterized by TEM and XRD analysis. The TEM image indicated a relatively uniform size and shape of the Ag-Cu NPs, with the particle diameter about 20-30 nm.A copper-silver nanoparticles-catalyzed coupling reaction of terminal alkynes to aldehydes was developed for the synthesis of propargyl alcohols. With the promotion of bipyridine ligand, the bimetallic catalyst showed highly efficient to the reaction under neat condition, and good to excellent yields were achieved for various propargylic alcohols. In this catalytic reaction, a remarkable bimetallic synergistic effect was observed, in which Ag NPs worked as the co-catalyst and improved the catalytic activity of Cu NPs significantly. The nanoparticles catalyst could be recovered and reused effectively, no obvious reduction on catalytic was observed after four recycles. Furthermore, a gram-scale reaction was also carried out successfully.On the other hand, a copper-silver nanopartices-catalyzed Sonogashira coupling-oxidationcyclization three-step tandem reaction of terminal alkynes and o-halide substituted benzaldehyde was developed for the synthesis of 3-alkylphthalides derives with TBHP as oxidant. With the promotion of triphenylphosphine oxide, the bimetallic catalyst showed highly efficient to the reaction in acetonitrile solution, and mediate to good yields were achieved for various phthalides derives. The synergistic effect of copper and silver were also observed in reaction.