文献类型：期刊文献

英文题名：Potassium complexes supported by monoanionic tetradentate amino-phenolate ligands: synthesis, structure and catalysis in the ring-opening polymerization of rac-lactide

作者：Yao, Chenhui;Yang, Yang;Xu, Shaoan;Ma, Haiyan[1]

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

年份：2017

卷号：46

期号：18

起止页码：6087

外文期刊名：DALTON TRANSACTIONS

收录：;EI(收录号：20172803902693);WOS:【SCI-EXPANDED(收录号:WOS:000400986500038)】；

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

语种：英文

外文关键词：Ligands - Synthesis (chemical) - Spectroscopic analysis - X ray diffraction - Chelation - Potassium compounds

摘要：A series of potassium complexes bearing monoanionic tetradentate amino-phenolate ligands, [LK](2) (L = {(2-R-1)C6H4CH2N[(CH2)(2)R-2]CH2(4-R-4-6-R-3)C6H2O-}, R-1 = NMe2, R-2 = NEt2, R-3 = CPh3, R-4 = Me (1); R-1 = R-2 = NEt2, R-3 = CPh3, R-4 = Me (2); R-1 = NMe2, R-2 = NEt2, R-3 = R-4 = cumyl (4); R-1 = R-2 = OMe, R-3 = Bu-t, R-4 = Me (6); L = (2-NMe2) C6H4CH2N[[CH2-(S)-1-butylpyrrolidinyl] CH2(4-Me-6-CPh3) C6H2O-] (3)), have been synthesized via reactions of KN(SiMe3)(2) and 1 equiv. of the corresponding aminophenols. The solid-state structures of typical complexes 4 and 6 are determined via X-ray diffraction studies, which reveal the dinuclear nature of these complexes. By contrast, DOSY measurements of 1, 4 and 6 suggest that these complexes are monomeric in solution. It is noteworthy that the coordination chemistry of these potassium complexes is versatile, which is closely related to the nature of the ortho-substituent of the phenolate ring, as indicated by the results of the corresponding spectroscopic studies. In the presence of (PrOH)-Pr-1, 1-4 and 6 could initiate the polymerization of 500 equiv. of rac-lactide to achieve high monomer conversions within several minutes but afford atactic PLAs with slightly isotactic-enriched microstructures (Pm = 0.58-0.60). Experimental results also demonstrated that a bulky trityl substituent at the ortho-position of the phenolate ring of the ligand framework is beneficial for the enhancement of the activities of these potassium complexes.