Synthesis and Characterization of N,N,O-Tridentate Aminophenolate Zinc Complexes and Their Catalysis in the Ring-Opening Polymerization of Lactides

Frontiers in Chemistry

Kuo-Hui Wu¹  Wei-Yi Lu²  Chu-Chieh Lin²  Hsuan-Ying Chen³ 

[1] Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan;Department of Chemistry, National Chung Hsing University, Taichung, Taiwan;Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan;Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan;

关键词: zinc;    polymerization;    catalyst;    lactide;    kinetic;   

DOI  :  10.3389/fchem.2019.00189

来源: DOAJ

【 摘 要 】

A series of aminophenolate ligands with various pendant groups and associated ethyl Zn complexes were synthesized and studied as catalysts for the ring-opening polymerization (ROP) of lactides (LAs). The thiophenylmethyl group (L4ZnEt) increased the catalytic activity more than the benzyl group (L1ZnEt) did, and 2-fluorobenzyl (L3ZnEt) and 2-methoxybenzyl (L2ZnEt) groups had the opposite effect. In addition, the LA polymerization mechanism proved by Nuclear Magnetic Resonance and Density Function Theory was that LA was attracted by H···O bond of an α-hydrogen of the LA molecule and the phenoxyl oxygen of the catalyst. After the dissociation of amino group from the Zn atom, the benzyl alcohol initiated LA without replacing the ethyl group of Zn complex. It is the first case where the ethyl group is regarded as a ligand and cannot be replaced by benzyl alcohol, and this information is very important for the mechanism study of ROP.

【 授权许可】

Unknown