An efficient route to macrocyclic polymers via “click” cyclization was presented.The α-bromine and ω-alkyne PMMA were prepared using the standard ATRP technique,initiated with propargyl 2-bromoisobutyrate,Cu(Ⅰ)Br...An efficient route to macrocyclic polymers via “click” cyclization was presented.The α-bromine and ω-alkyne PMMA were prepared using the standard ATRP technique,initiated with propargyl 2-bromoisobutyrate,Cu(Ⅰ)Br and N,N,N’,N″,N-pentamethyldiethylenetriamine(PMDETA).Azidation of the terminal bromine was followed in DMF with sodium azide,and α-azide,ω-alkyne PMMA precursor was obtained.Then the “click” cylcization of precursor between terminal azide and alkyne was carried out under the catalysis of CuBr/PMDETA,during the course of the reaction,a pseudo-high dilution technique was utilized to ensure the favored intramolecular cylcization.The nearly complete cylcization has been confirmed by a combination of IR,1H NMR and GPC analysis,and cyclo-PMMA with an Mn of 15000,PDI of 1.38 was obtained.展开更多
A new approach to the synthesis of dendrimer-like star polymer,[(PMMA)2PSt]4,was presented via the combination of atom transfer radical polymerization(ATRP) and ckick chemistry.Firstly four-arm bromine-terminated poly...A new approach to the synthesis of dendrimer-like star polymer,[(PMMA)2PSt]4,was presented via the combination of atom transfer radical polymerization(ATRP) and ckick chemistry.Firstly four-arm bromine-terminated polystyrene(PSt-Br)4 was obtained from ATRP of styrene using pentaerythritol tetra(2-bromoisobutyrate) as an initiator,and the(PSt-Br)4 was efficiently converted to the azido-terminated polymers[(PSt-N3)4] through the bromine substitution reaction with sodium azide.Furthermore,the(PSt-N3)4 reacted with propargyl 2,2-bis[2-(bromomethyl)propionato]propionyrate via a click reaction,1,3-dipolar cycloaddition reaction,and the polymer[(PSt-Br2)4] containing eight end-bromine was obtained.The(PSt-Br2)4 could further serve as a macroinitiator for the ATRP of methyl methacrylate(MMA).Accordingly,the dendrimer-like star polymer,[(PMMA)2PSt]4 was successfully prepared.The structure of [(PMMA)2PSt]4 was characterized via IR,1H NMR,GPC and DSC.展开更多
文摘An efficient route to macrocyclic polymers via “click” cyclization was presented.The α-bromine and ω-alkyne PMMA were prepared using the standard ATRP technique,initiated with propargyl 2-bromoisobutyrate,Cu(Ⅰ)Br and N,N,N’,N″,N-pentamethyldiethylenetriamine(PMDETA).Azidation of the terminal bromine was followed in DMF with sodium azide,and α-azide,ω-alkyne PMMA precursor was obtained.Then the “click” cylcization of precursor between terminal azide and alkyne was carried out under the catalysis of CuBr/PMDETA,during the course of the reaction,a pseudo-high dilution technique was utilized to ensure the favored intramolecular cylcization.The nearly complete cylcization has been confirmed by a combination of IR,1H NMR and GPC analysis,and cyclo-PMMA with an Mn of 15000,PDI of 1.38 was obtained.
文摘A new approach to the synthesis of dendrimer-like star polymer,[(PMMA)2PSt]4,was presented via the combination of atom transfer radical polymerization(ATRP) and ckick chemistry.Firstly four-arm bromine-terminated polystyrene(PSt-Br)4 was obtained from ATRP of styrene using pentaerythritol tetra(2-bromoisobutyrate) as an initiator,and the(PSt-Br)4 was efficiently converted to the azido-terminated polymers[(PSt-N3)4] through the bromine substitution reaction with sodium azide.Furthermore,the(PSt-N3)4 reacted with propargyl 2,2-bis[2-(bromomethyl)propionato]propionyrate via a click reaction,1,3-dipolar cycloaddition reaction,and the polymer[(PSt-Br2)4] containing eight end-bromine was obtained.The(PSt-Br2)4 could further serve as a macroinitiator for the ATRP of methyl methacrylate(MMA).Accordingly,the dendrimer-like star polymer,[(PMMA)2PSt]4 was successfully prepared.The structure of [(PMMA)2PSt]4 was characterized via IR,1H NMR,GPC and DSC.
