文献类型：期刊文献

英文题名：Zinc complexes supported by multidentate aminophenolate ligands: synthesis, structure and catalysis in ring-opening polymerization of rac-lactide

作者：Wang, Liying[1];Ma, Haiyan[1]

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

年份：2010

卷号：39

期号：34

起止页码：7897

外文期刊名：DALTON TRANSACTIONS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000281109800010)】；

基金：This work is subsidized by the National Basic Research Program of China (2005CB623801), National Natural Science Foundation of China (NNSFC, 20604009 and 20774027), the Program for New Century Excellent Talents in University (for H. Ma, NCET-06-0413) and the Fundamental Research Funds for the Central Universities (WK0914042). All the financial supports are gratefully acknowledged. H. Ma also thanks the very kind donation of a Braun glove-box by AvH foundation.

语种：英文

摘要：Monomeric zinc silylamido and ethyl complexes bearing tetradentate aminophenolato ligands [(DNNO)ZnR] (D = NMe2, OMe; R = N(SiMe3)(2) (1-5, 8), Et (6, 7, 9, 10)), were isolated from the reaction of Zn[N(SiMe3)(2)](2) or ZnEt2 and one equivalent of aminophenols {aryl-CH2N[(CH2)(2)NMe2]CH2-phenol} in moderate to high yields. The monomeric nature of these complexes was further confirmed by X-ray diffraction studies of silylamido complexes 1, 3 and ethyl complexes 7, 9, 10. The methoxy or N,N-dimethylamino group of the aryl unit does not coordinate with the metal center in the solid state, only the remaining three donors of the ligand and silylamido or ethyl group interact with zinc center constructing a distorted tetrahedral coordination geometry at the metal center. All these zinc complexes efficiently initiated the ring-opening polymerization of rac-lactide, and the polymerization runs were better controlled in the presence of isopropanol, giving atactic PLAs end-capped with isopropyl ester and hydroxyl groups. The structure of the ancillary ligands showed some influence on the catalytic activity and selectivity of the corresponding zinc complexes. The introduction of bulky ortho-substituents on the phenoxy unit resulted in a decrease of the polymerization rate, whereas the isotactic dyad selectivity in the ROP of rac-lactide was enhanced.