Post-functionalized Modification Of Ether-containing Disubstituted Polyacetylenes

Poly(diphenyl-substituted acetylenes)(PDSAs)have shown remarkably modified properties such as high emission efficiency and high thermal stability in comparison with the counterparts of poly(mono-substituted acetylenes),thus found promising applications as gas separation membranes,polymeric fluorescent probes,emissive elastomers.The preparation of functional PDSAs is one of the major branches in the PDSAs research.However,the design and synthesis of functionalized PDSAs are still challenging tasks.Because of the poisoning effect of high polar functional groups on transition metal catalysts,acetylene monomers bearing active protons are unable to be directly conversed to the corresponding polymers so far,greatly limiting the further exploration of the functionalized PDSAs.Luckily,thanks to the introduction of the post polymerization modification strategy(PPM)the thorny problem has been partly solved.Different modification polymer derivatives can be obtained from same parent polymer containing reactive sites through PPM strategy.So far,the Pd catalyzed coupling reaction,thiol-ene click reaction,Micheal addition reaction and Cu(I)catalysed alkyne-azide click reaction has been widely applied in the preparation of functionalized PDSAs.As the scope of the post polymerization modification is still limited by the reaction of reactive sites,the exploration of more new and interesting functionalized PDSAs is still in desperate need.Therefore,two new parent PDSAs containing reactive sites as ester groups were investigated here in a desire to furtherly enrich the strategies of PDSAs functionalization.First,several diphenyl-disubstituted acetylene monomers containing different protective groups were prepared.After the initial exploration,the phenol-containing PDSA was obtained by the polymerization of the triisopropylsilan(TIPS)-protected 4-((4fluorophenyl)ethynyl)phenol monomer and the subsequent a de-protection step.A new synthetic strategy was explored to derive functional poly(disubstituted acetylenes)(PDSAs)through "phenol-yne click reaction".Then,different functional groups(e.g.,ester and amide)were grafted onto the PDSA side chains via the highly efficient "phenol-yne click reaction".The post polymerization modification was carried out in mild condition(40℃,Common solvent)under air atmosphere for a short time(4 h).The structures of the products were well characterized by GPC,NMR,and FTIR techniques and satisfactory data were collected.The second work focus on the preparation of a clickable PDSA containing two functionalization groups.The epoxy-thiol click reaction is commonly used in the post polymerization modification,which has advantages like mild condition,high efficiency.What’s more,the PDSA with epoxy group has not been investigated so far.Thus epoxy functionalized PDSAs were synthesized from a parent polymer containing allyl ether group on the side chain through the epoxidation reaction.Also the ratio of the epoxy/ene groups could be tuned by controlling the conditions of different reactions thus could be flexible used to satisfy different applications.