文献类型：期刊文献

英文题名：Well-Controlled Ring-Opening Polymerization of Cyclic Esters Catalyzed by Aluminum Amido Complexes: Kinetics and Mechanism

作者：Liu, Junpeng;Ma, Haiyan[1]

机构：[1]E China Univ Sci & Technol, Shanghai Key Lab Funct Mat Chem, Shanghai 200237, Peoples R China; E China Univ Sci & Technol, Lab Organometall Chem, Shanghai 200237, Peoples R China

年份：2014

卷号：52

期号：21

起止页码：3096

外文期刊名：JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY

收录：;EI(收录号：20152901046309);WOS:【SCI-EXPANDED(收录号:WOS:000342830600011)】；

基金：Financial supports from the National Natural Science Foundation of China (NNSFC, 21074032 and 21274041) and the Fundamental Research Funds for the Central Universities (WK1214048 and WD1113011) are gratefully acknowledged.

语种：英文

外文关键词：aluminum complex; amido ligand; catalysis; polyesters; ring-opening polymerization

摘要：A series of aluminum dimethyl complexes 1-6 bearing N-[2-(pyrrolidinyl) benzyl] anilido ligands were synthesized and well characterized. The molecular structure of complex 1 determined by an X-ray diffraction study indicates the bidentate chelating mode of the pyrrolidinyl-anilido ligand. In the absence of a coinitiator, these complexes exhibited excellent control toward the polymerizations of epsilon-caprolactone and raclactide, affording polyesters with quite narrow molecular weight distributions (M-w/M-n = 1.04-1.26). The end group analysis of epsilon-CL oligomer via H-1 NMR and ESI-TOF MS methods gave strong support to the hypothesis that the polymerization catalyzed by these aluminum complexes proceeds via a coordination-insertion mechanism involving a unique Al-N (amido) bond initiation. Via H-1 NMR scale oligomerization studies, it is suggested that the insertion of the first lactide monomer into Al-N bond of the complex is much easier than the insertion of lactide monomer into the newly formed Al-O (lactate) bond and might also be easier than the insertion of the first epsilon-CL monomer into Al-N bond. (c) 2014 Wiley Periodicals, Inc.