文献类型：期刊文献

英文题名：Zinc complexes supported by claw-type aminophenolate ligands: synthesis, characterization and catalysis in the ring-opening polymerization of rac-lactide

作者：Song, Shaodi;Zhang, Xingyu;Ma, Haiyan[1];Yang, Yang

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：2012

卷号：41

期号：11

起止页码：3266

外文期刊名：DALTON TRANSACTIONS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000300737900023)】；

基金：This work is subsidized by the National Natural Science Foundation of China (NNSFC, 20604009 and 21074032), the Program for New Century Excellent Talents in University (for H. Ma, NCET-06-0413), Science and Technology Commission of Shanghai Municipality (STCSM, contract no. 10dz2220500), 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：A series of zinc silylamido complexes bearing claw-type multidentate aminophenolate ligands, [LZnN(SiMe3)(2)] (L = -OAr1-CH2N[(CH2)(n)NR2]CH2Ar2, n = 2 or 3; R = Me or Et (1a-3a, 5a, 7a and 8a); L = -OC6H2-4,6-Bu-t(2)-2-CH2N[(CH2)(2)OMe](2) (9a)), have been synthesized via the reaction of Zn [N(SiMe3)(2)](2) and 1 equiv. of corresponding aminophenol. The reaction of Zn[N(SiMe3)(2)](2) with the proligand (LH)-H-6 (2-{N-(2-methoxybenzyl)-N-[3-(N',N'-dimethylamino) propyl]aminomethyl}-4-methyl-6-tritylphenol) resulted in the formation of bisphenolate zinc complex 6 regardless of the stoichiometric ratio of the two starting materials. Complex 4b with an initiating group of 3-tert-butyl-2-methoxy-5-methylbenzyloxy was obtained and further studied via the X-ray diffraction method to be monomeric. Zinc ethyl complex 2c was also prepared from the reaction of ZnEt2 and 1 equiv. of proligand (LH)-H-2 as the representative complex with an alkyl initiating group. All zinc silylamido complexes efficiently initiated the ring-opening polymerization of rac-lactide in the presence or absence of isopropanol at ambient temperature. The steric and electronic characteristics of the ancillary ligands significantly influenced the polymerization performance of the corresponding zinc complexes. The introduction of bulky ortho-substituents on the phenoxy moiety resulted in an apparent decrease of catalytic activity while a slightly enhanced isotactic selectivity. Meanwhile, the elongation of the pendant amine arm to three-carbon-atom linkage led to significant decline of the catalytic activity in the absence of isopropanol. The zinc ethyl complex 2c was not such an efficient initiator as the silylamido ones, but the alkoxy complex 4b gave an obviously faster and better controlled polymerization when compared to the zinc silylamido complexes.