文献类型：期刊文献

英文题名：Aluminum complexes with bidentate amido ligands: synthesis, structure and performance on ligand-initiated ring-opening polymerization of rac-lactide

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：43

期号：24

起止页码：9098

外文期刊名：DALTON TRANSACTIONS

收录：;EI(收录号：20142317794826);WOS:【SCI-EXPANDED(收录号:WOS:000336840900017)】；

基金：This work was subsidized by the National Natural Science Foundation of China (NNSFC, 20604009, 21074032), the Program for New Century Excellent Talents in University (for H. Ma, NCET-06-0413) and the Fundamental Research Funds for the Central Universities (WD1113011, WK1214048). All financial support is gratefully acknowledged. H. Ma also thanks the very kind donation of a Braun glove-box by AvH foundation.

语种：英文

外文关键词：X ray diffraction - Chelation - Ring opening polymerization - Mass spectrometry - Molecular weight distribution - Nuclear magnetic resonance spectroscopy - Synthesis (chemical) - Aluminum compounds - Catalyst activity

摘要：A series of mononuclear aluminum dimethyl complexes bearing bidentate N-[2-(1-piperidinyl)benzyl]anilino or N-(2-morpholinobenzyl)anilino ligands were synthesized via reactions of the corresponding proligands with trimethylaluminum upon heating, while at ambient temperature two trimethylaluminum adducts with neutral N-[2-(1-piperidinyl)benzyl]aniline proligands were obtained. These complexes were well characterized by NMR spectroscopy, elemental analysis and occasionally by EI-HRMS. The molecular structures of the typical trimethylaluminum adduct 2b and aluminum dimethyl complex 3b were further confirmed by X-ray diffraction studies. All the aluminum dimethyl complexes could effectively initiate the ring-opening polymerization (ROP) of rac-lactide in a well-controlled manner to afford PLAs with narrow molecular weight distributions (PDI = 1.06-1.18). The polymer samples obtained are systematically end-capped with the bidentate ancillary ligands as characterized by H-1 NMR and ESI-TOF mass spectroscopy. Moreover, the introduction of substituent(s) at the ortho-position(s) of the anilino moiety in the ligand results in an obvious decrease in the catalytic activity of the corresponding aluminum complex, and complexes with meta-chloro substituted anilino units show higher activities likely due to the enhanced electrophilicity of the metal centers induced by the anilino groups.