DFT Studies on Isoprene/Ethylene Copolymerization Catalyzed by Cationic Scandium Complexes Bearing Different Ancillary Ligands

作     者：Xiaojie Hu Xiaohui Kang Guangli Zhou Xingbao Wang Zhaomin Hou Yi Luo 

作者机构：State Key Laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology Dalian Liaoning 116024 China Organometallic Chemistry Laboratory and Center for Sustainable Resource Science RIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan College of Pharmacy Dalian Medical University Dalian Liaoning 116044 China 

出 版 物：《Chinese Journal of Chemistry》 (中国化学（英文版）)

年 卷 期：2017年第35卷第5期

页      面：723-732页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070305[理学-高分子化学与物理] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 

基　　金：国家自然科学基金 a Grant-in-Aid for Scientific Research (S) from the JSPS 

主　　题：DFT ethylene/isoprene copolymerization rare earth metal 

摘      要：The isoprene/ethylene copolymerization catalyzed by cationic rare earth metal complexes [（η5-C5Me5）Sc（CH2SiMe3）]＋ （A） had afforded alternating isoprene-ethylene copolymer with rich 3,4-polyisoprene microstructures,whereas no isoprene-ethylene copolymer was observed by using analogous [（PNpPh）Nc（CH2SiMe3）]＋ （B） under the same *** calculations in this work have revealed that,in the case of A,successive 3,4-insertion of isoprene resulted in a noncovalent interaction between the C =C double bond of penultimate unit and the metal center,suppressing the further insertion of monomers due to higher energy barrier and endergonic *** the other hand,the ethylene pre-inserted species with alkyl active site is more suitable for the subsequent kinetically and thermodynamically favorable isoprene insertion and copolymerization is therefore *** the case of B,the experimentally observed cis-l,4-specific homopolymerization of isoprene was the outcome of both kinetic and thermodynamic ***,the unfavorable ethylene insertion into the isoprene pre-inserted species with allyl active site could account for the experimental finding that no isoprene-ethylene copolymer was *** computational results are expected to provide some hints for the design of rare earth copolymerization catalysts.