Study On The C-C Coupling Reactions Of Arenediazonium Tetrafluooroborate Salts Catalyzed By Pd-MOF

Metal-organic frameworks(MOFs)are porous coordination polymers which are composed of metal ions and organic ligands by covalent bond or ion covalent bond.In the past few years,with the continuous optimization of synthesis strategy,the disadvantages of MOF materials in the field of catalysis,such as poor stability and encapsulation of catalytic sites,have been overcome.The catalysis based on MOFs materials has entered a rapid development period.Coupling reaction is an important method for the construction of C-C bond.The developing of some environmental benign coupling processes is becoming a very urgent project for chemists.High catalytic activity homogeneous palladium metal catalytic system usually needs to add expensive phosphine ligands,which is not conducive to the separation of products and catalyst recycling.However,heterogeneous catalysts often lack sufficient activity and stability for inert substrates or substrates with large steric hindrance.In this paper,Pd-MOF was synthesized as catalyst in Suzuki coupling reaction and Heck reaction.The main contents are as follows:(1)Study on the Suzuki coupling reaction of arenediazonium tetrafluoroborate salts catalyzed by Pd-MOF: The 2-(carboxyethyl)benzenediazonium tetrafluoroborate and phenylboronic acid was selected as reaction template.The catalytic activity of Pd-MOF was verified by comparative control experiments.Subsequently,the effect of catalyst loading,solvents and reaction temperature on the cross-coupling reaction was investigated.Under the optimal reaction conditions of 3mol% Pd-MOF,methanol and 40 ?,a variety of arenediazonium tetrafluoroborate salt and arylboronic acids were investigated to ascertain the scope and limitations of this reaction.The Pd-MOF could be recycled and reused three times without a significant reduction in the yield.(2)Study on Heck coupling reation of arenediazonium tetrafluoroborate salts catalyzed by Pd-MOF: The reaction conditions were optimized in the reaction of phenyltetrafluoroborate diazonium salt and methyl acrylate.Some of arenediazonium tetrafluoroborate salts reacted with arylboronic acids to ascertain the scope and limitations of this reaction.The systematic research work of this part is still in progress in our labrotary.The above experimental results showed that Pd-MOF was a potential heterogeneous palladium catalyst with high catalytic performance and can be reused for many times in the C-C coupling reaction of arenediazonium tetrafluoroborate salts.