Metal-free Multicomponent Polymerization Of Activated Alkyne,formaldehyde And Amine

Multicomponent polymerizations(MCPs)have drawn much attention due to its high efficiency,high convenience,and environmental benefit.At present,monomers of MCPs mainly include isocyanide,alkyne,amine,aldehyde,azide,acid,?-ketoester,thiourea,urea,etc.The most widely explored MCPs are the isocyanide-based and alkyne-based MCPs.As a rapidly developing field in MCPs,Alkyne-based MCPs possess a series of advantages such as safety,non-toxic and non-smelly alkyne monomers,and most importantly,the potential of the preparation of unsaturated polymers.But most of the reported alkyne-based MCPs adopt metal catalysts,which result in metallic residues in polymer products and limits the application of polymers in optoelectronics and biology.To solve the above problems,in this thesis,we devoted to explore new metal-free/catalyst-free alkyne-based MCPs.Diester-activated internal alkynes which are easily synthesized and stable at room temperature were selected as the monomer because of their rich chemical properties and high reactivity.Firstly,a facile metal-free one-pot multicomponent tandem polymerization(MCTP)of activated internal alkynes,aromatic diamines,and formaldehyde was developed for the synthesis of structural-regulated and sequence-controlled polyheterocycles with high molecular weights(Mw up to 69 800 g/mol)in high yields(up to 99%).By the method of MCTP,polymers with the in situ generated multisubstituted tetrahydropyrimidines or dihydropyrrolones in the polymer backbone and inherent luminescence can be easily obtained with high atom economy and environmental benefit,which are unavailable through other synthetic approaches.Secondly,a catalyst-free alkyne-based MCTP was developed based on activated alkynes,aliphatic diamines and formaldehyde.Through this polymerization method,polycyclic pyrimidine with well-defined structure,high molecular weights(Mw up to 56 700 g/mol)can be obtained in high yields(up to 84%).Comparing with the previous polymerization method,the amine monomers in this MCTP are extended to the aliphatic amine.Since this MCTP did not use acetic acid,the salt formed from acetic acid and aliphatic amine was avoided.In this system,aliphatic amines are more active than aromatic amines,which will result in byproducts.Therefore,the strategy of adding the aliphatic amines in two steps was adopted to avoid the formation of by-products and achieve good polymerization results.