Preparation Of Porous Organic Polymers-supported Metal Catalysts And Application In The N-formylation And Alkyne Oxidation Reaction

Porous organic polymers have attracted more attention due to their unique cavity structure,high specific surface area and excellent thermal stability.In addition,porous organic polymer is used as a carrier to support metals to participate in heterogeneous catalytic reactions,which can play a role in the recovery and recycling of precious metals.In this paper,a series of heterogeneous catalysts supported by porous organic polymers have been designed and synthesized for N-formylation and alkyne oxidation reaction.Firstly,we reported a series of pyridine-doped PPh₃-based POPs（POPs-Py&PPh₃）including different molar ratios of PPh₃and pyridine moieties.After treatment of the copolymers with Ru Cl₃,the corresponding porous organic polymer supported ruthenium catalysts（Ru/POPs-Py&PPh₃）were synthesized.Confirmed by experimental comparison,the ratio of monomer polymerization has an impact on the reaction,and the porous organic polymer supported ruthenium catalyst（Ru/POP₃-Py&PPh₃）showed the best catalytic activity in the N-formylation of amines with CO₂/H₂.Various primary and secondary amines are amenable to the procedure,affording the corresponding formamides in good yields and excellent recyclability under relatively mild reaction conditions.Porous organic polymer-supported ruthenium catalysts showed high catalytic activity with TON values of 710 and good yields（55–95%）.The heterogeneous catalyst can be easily separated from the reaction system and reused for at least eight cycles in the N-formylation.Secondly,through the self-polymerization of tris（4-vinyl）triphenylphosphine monomer,a porous organic polymer（POP-PPh₃）was generated.POP-POPh₃was prepared via oxygenation of POP-PPh₃with hydrogen peroxide.Subsequent treatment of the copolymer with Pd Cl₂and Cu Br₂readily furnished Pd&Cu/POP-POPh₃,which was successfully used in the oxidation of the alkynes affording the 1,2-diketones.Confirmed by experiment,the heterogeneous catalyst showed high catalytic activity and good yields（76-99%）with wide substrate compatibility.In the process of cyclic reaction,the catalyst can still remain catalytic activity after simple separation and at least six cycles in the alkyne oxidation reaction.