Partially biobased polysilylethers(PSEs)are synthesized via dehydrocoupling polymerization catalyzed by an anionic iridium complex.Different types(AB type or AA and BB type)of monomers are suitable.Levulinic acid(LA)a...Partially biobased polysilylethers(PSEs)are synthesized via dehydrocoupling polymerization catalyzed by an anionic iridium complex.Different types(AB type or AA and BB type)of monomers are suitable.Levulinic acid(LA)and succinic acid(SA)have been ranked within the top 10 chemicals derived from biomass.BB type monomers(diols)derived from LA and SA have been applied to the synthesis of PSEs.The polymerization reactions employ an air-stable anionic iridium complex bearing a functional bipyridonate ligand as catalyst.Moderate to high yields of polymers with number-average molecular weights(Mn)up to 4.38×104 were obtained.A possible catalytic cycle via an Ir-H species is presented.Based on the results of kinetic experiments,apparent activation energy of polymerization in the tempe rature range of 0-10℃is about 38.6 kJ/mol.The PSEs synthesized from AA and BB type monomers possess good thermal stability(T5=418℃to 437℃)and low glass-transition temperature(Tg=49.6℃).展开更多
The synthesis and characterization of chiral polymers with diverse structure remain a long-term challenging research topic.Herein,a copper-catalyzed enantioselective insertion of carbene into Si-H bond was applied to ...The synthesis and characterization of chiral polymers with diverse structure remain a long-term challenging research topic.Herein,a copper-catalyzed enantioselective insertion of carbene into Si-H bond was applied to polycondensation,giving a new type of optically active degradable polyesters containing Si-C bond in the main chain.The polymerization features mild condition,broad substrate scope,excellent yields and enantioselectivities.Chiral diols could be obtained via reduction of optically active polyesters.Thermogravimetric analysis indicated these chiral polyesters exhibit good thermal stability.展开更多
基金Financial support from the National Natural Science Foundation of China(No.21690074)Dalian Bureau of Science and Technology(No.2016RD07)Chinese Academy of Sciences(No.XDB17020300)。
文摘Partially biobased polysilylethers(PSEs)are synthesized via dehydrocoupling polymerization catalyzed by an anionic iridium complex.Different types(AB type or AA and BB type)of monomers are suitable.Levulinic acid(LA)and succinic acid(SA)have been ranked within the top 10 chemicals derived from biomass.BB type monomers(diols)derived from LA and SA have been applied to the synthesis of PSEs.The polymerization reactions employ an air-stable anionic iridium complex bearing a functional bipyridonate ligand as catalyst.Moderate to high yields of polymers with number-average molecular weights(Mn)up to 4.38×104 were obtained.A possible catalytic cycle via an Ir-H species is presented.Based on the results of kinetic experiments,apparent activation energy of polymerization in the tempe rature range of 0-10℃is about 38.6 kJ/mol.The PSEs synthesized from AA and BB type monomers possess good thermal stability(T5=418℃to 437℃)and low glass-transition temperature(Tg=49.6℃).
基金Financial support from the National Natural Science Founda-tion of China(21690074)Dalian Institute of Chemical Physics(UN201701)the Chinese Academy of Sciences(XDB17020300)。
文摘The synthesis and characterization of chiral polymers with diverse structure remain a long-term challenging research topic.Herein,a copper-catalyzed enantioselective insertion of carbene into Si-H bond was applied to polycondensation,giving a new type of optically active degradable polyesters containing Si-C bond in the main chain.The polymerization features mild condition,broad substrate scope,excellent yields and enantioselectivities.Chiral diols could be obtained via reduction of optically active polyesters.Thermogravimetric analysis indicated these chiral polyesters exhibit good thermal stability.
