Study On Csp-Csp Coupling Reaction Catalyzed By Amidoxime Fiber Supported Bimetallic Complexes

Because of its conjugated structure,1,3-diyne has a wide range of applications in biomedicine,photoelectric materials,and synthetic intermediates.In this work,AOFs-supported metal catalysts are used to catalyze the Csp-Csp cross-coupling of terminal alkynes,mainly including the coupling reactions of alkyne halides and terminal alkynes,cross-coupling reactions of different aromatic alkynes,and aromatics.The three major systems of the cross-coupling reaction of alkyne and aliphatic terminal alkynes.In the amidoxime-supported bimetallic catalyst system,these reactions can be achieved well and have a considerable yield.We characterized the catalyst of this system,and on this basis,we carried out a series of auxiliary experiments and obtained a more reasonable reaction mechanism.At the same time,we also completed the process optimization,derivative development,and catalyst reuse performance of this reaction system.The result is as follows:1.Polyacrylonitrile fiber was used as raw material,modified by hydroxylamine solution under 70°C water bath and modified to obtain modified polyacrylonitrile fiber?AOFs?.The prepared polyacrylonitrile fibers were put into a coordination reaction with a palladium chloride solution to prepare a fiber-supported palladium ion complex?Pd?II?-AOFs?,and characterized by SEM,XPS,and EDS.2.The prepared Pd?II?-AOFs catalyst are used to catalyze the cross-coupling reaction of an alkyne halide with an alkyne.The effects of different catalysts on the catalytic activity of the reaction were investigated.The bimetallic catalysts Cu?I?/Pd?II?-AOFs with the best catalytic activity and selectivity for the cross-coupling of alkyne halides and terminal alkynes were selected.At the same time,the effects of solvents,base reagents,the amount of catalyst,reaction temperature and reaction time on the catalytic activity and selectivity of the catalyst were investigated.The reusability of Pd?II?-AOFs was also investigated to optimize the optimal reaction conditions:at 65°C.Using 75%ethanol as the solvent and triethylamine as the base reagent,1equiv of CuCl and 0.02 equiv of Pd?II?-AOFs catalyze the reaction between the alkyne halide and the terminal alkyne for 2 hours to achieve the best yield,and the yield can reach 93%.Moreover,the system has good adaptability to aliphatic and aromatic terminal alkynes,and Pd?II?-AOFs can be used in this system for five times with higher yield.3.The prepared Pd?II?-AOFs catalyst are used to catalyze the cross-coupling reaction between different aromatic terminal alkynes.The effect of different catalysts on the catalytic activity of this reaction was investigated,and the Cu?I?+Pd?II?-AOFs synergistic catalyst with the best catalytic activity and selectivity for cross coupling between different aromatic terminal alkynes was selected.At the same time,the effects of solvents,base reagents,reaction temperature,the amount of catalyst,and reaction time on the catalytic activity and selectivity of the catalyst were investigated.The repeated use of Pd?II?-AOFs was investigated to optimize the optimal reaction conditions:at70°C,using DMAc as the solvent and Et₃N as the base reagent,add 1 equivalent of CuCl and 0.02 equivalent of Pd?II?-AOFs catalyst different aromatic terminal alkynes reacted for 2 hours to achieve the best yield,the yield reached 71%,and the system had better adaptability to aromatic terminal alkynes.And Pd?II?-AOFs can be reused in this system for four times with higher yields.4.The prepared Pd?II?-AOFs were used to catalyze the cross-coupling reaction between aromatic terminal alkynes and aliphatic terminal alkynes,and the process optimization was completed.The influences of solvents,alkali reagents,amount of catalyst,reaction temperature,and reaction time on the catalytic activity of the catalyst were investigated.The repeated use performance of Pd?II?-AOFs was explored and optimized.Optimum reaction conditions:at 70°C,using DMAc as solvent,Et₃N as base reagent,1equiv CuCl and 0.015 equiv of Pd?II?-AOFs catalyzed the reaction between aromatic terminal alkynes and aliphatic terminal alkynes for 2 hours to achieve the best yield,yield of 63%,and the system Aliphatic and aromatic terminal alkynes have good adaptability,and Pd?II?-AOFs can be used repeatedly in this system for four times with higher yields,and the bimetallic synergistic catalytic mechanism is preliminarily explored.The possible mechanism of Cu?I?+Pd?II?-AOFs bimetallic catalyst catalyzed cross-coupling of aromatic terminal alkynes with aliphatic terminal alkynes was obtained.