文献类型：期刊文献

英文题名：Exploring Steric Effects in Diastereoselective Synthesis of Chiral Aminophenolate Zinc Complexes and Stereoselective Ring-Opening Polymerization of rac-Lactide

作者：Wang, Haobing;Yang, Yang;Ma, Haiyan[1]

机构：[1]East China Univ Sci & Technol, Shanghai Key Lab Funct Mat Chem, 130 Meilong Rd, Shanghai 200237, Peoples R China; East China Univ Sci & Technol, Lab Organometall Chem, 130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2016

卷号：55

期号：15

起止页码：7356

外文期刊名：INORGANIC CHEMISTRY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000380864900027)】；

基金：This work is subsidized by the National Natural Science Foundation of China (NNSFC, 21074032 and 21474028), and the Fundamental Research Funds for the Central Universities (WD1113011). All the financial support is gratefully acknowledged. H. Ma also thanks the very kind donation of a Braun glovebox by AvH foundation.

语种：英文

摘要：A series of tridentate chiral aminophenol proligands and corresponding zinc complexes, LZnX (L = (S)-2-{[(1-R-4-2-pyrrolidinyl)CH2N(R-3)-]CH2}-6-R-1-4-R-2-C6H2O, X = N(SiMe3)(2) = N(SiMe3)(2), R-3 = '' Bu, R-4 = Bn: R-1 = R-2 = Cl (1), R-1 = R-2 = Me (2), R-1 = R-2 = Bu-t (3); X = N(SiMe3)(2), = R-1 = trityl, R-2 = Me: R-3 = n-octyl, R-4 = Bn (4), R-3 = Bn, R-4 = Bn (5), R-3 = '' Bu, R-4 = naphthalen-1-ylmethyl (6), = R-3 = '' Bu, R-4 = Pr-i (7); R-1 = R-2 = cumyl, R-3 = Et, R-4 = Bn: X = N(SiMe3)(2) (8), X = (OBu)-Bu-t (9), X = Et (10), X = Cl (11)), have been synthesized. Complexes 4, 6, and 11 were obtained as enantiopure products (4 and 6 as enantiopure a; 11 as enantiopure b), while complexes 1-3, 5, and 7-10 as a pair of diastereomers, but in different ratios, which have been proved by X-ray diffraction and NMR spectroscopic studies. When exposed to the ring-opening polymerization of rac-lactide, most of these complexes can effectively produce PLAs with narrow polydispersities, desirable molecular weights, and moderate to high isotacticities. The structure-selectivity relationships, including the relationships of structure-synthesis diastereoselectivity and structure-polymerization stereoselectivity, have been further investigated. Consistent trends of diastereoselectivity and stereoselectivity are observed with the variations of the R-1 group at the ortho-position of the phenolate ring and the R-3 group in the pyrrolidinyl moiety. The decrease of the steric bulkiness of the R-4 group, on the central amine has less influence on the diastereoselectivity, but leads to considerable loss of the stereoselectivity, whereas the decrease of the steric bulkiness of the X group results in a reverse of the diastereoselectivity, but shows no influence on the stereoselectivity. There is probably no direct relationship between the diastereoselectivity in complex synthesis and the stereoselectivity of the complex toward the ROP of rac-LA. The stereocontrol of these complexes might largely rely on the substituents in the ligand framework rather than itheir diastereomer ratios.