High temperature ethylene polymerization catalyzed by titanium(<scp>iv</scp>) complexes with tetradentate aminophenolate ligands in cis-O, N, N chelating mode
作者:Ruiguo Zhao、Taotao Liu、Liying Wang、Haiyan Ma
DOI:10.1039/c4dt01122h
日期:——
tetradentate aminophenolate ligands were synthesized from the direct reaction of TiCl4(THF)2 with 1 equiv. of the corresponding aminophenol in the presence of triethylamine. For comparison purposes, titanium isopropoxide complexes 5e–8e were also synthesized via the reaction of Ti(OiPr)4 and 1 equiv. of the proligand. Similar reactions of ZrCl4(THF)2 with the corresponding aminophenol ligands in the presence
由TiCl 4(THF)2与1当量的直接反应合成了一系列与爪型四齿氨基酚盐配体连接的三氯化钛配合物1a-4a,7a-10a。在三乙胺存在下制备相应的氨基苯酚。为了进行比较,还通过Ti(O i Pr)4和1当量的反应合成了异丙醇钛络合物5e-8e。配体的。ZrCl 4(THF)2与相应的氨基苯酚配体在三乙胺存在下的类似反应仅允许分离锆配合物8b。X射线衍射研究表明,三氯化钛配合物2a,9a和三异丙氧基钛配合物5e均具有扭曲的八面体几何形状,四齿氨基酚酸酯配体处于顺式-O,N,N螯合模式,其中芳基单元的甲氧基确实存在在固态时不与金属中心协调。经MMAO活化后,这些钛和锆(IV)配合物在30–120°C的温度下对乙烯聚合表现出中等至高的催化活性,从而生产出分布广泛的高分子量聚乙烯(M w / M n= 10.2–34.8)。在高温下,三氯化钛配合物的活性明显高于异丙醇钛和三氯化锆配合物的活性。通
Zinc complexes supported by claw-type aminophenolate ligands: synthesis, characterization and catalysis in the ring-opening polymerization of rac-lactide
作者:Shaodi Song、Xingyu Zhang、Haiyan Ma、Yang Yang
DOI:10.1039/c2dt11767c
日期:——
alkyl initiating group. All zinc silylamido complexes efficiently initiated the ring-openingpolymerization 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 zinccomplexes. The introduction of bulky ortho- substituents on the phenoxy
一系列带有爪型多齿氨基酚盐配体[LZnN(SiMe 3)2 ](L = –OAr 1 -CH 2 N [(CH 2)n NR 2 ] CH 2 Ar 2,n = 2或3; R = Me或Et(1a-3a,5a,7a和8a); L = -OC 6 H 2 -4,6- t Bu 2 -2-CH 2 N [(CH 2)2 OMe] 2(9a)),是通过Zn [N(SiMe 3)2 ] 2与1当量的反应合成的。的对应氨基苯酚。Zn [N(SiMe 3)2 ] 2与配体L 6 H(2- N-(2-甲氧基苄基)-N- [3-(N ',N'-二甲基氨基)丙基]氨基甲基}-的反应不管两种起始材料的化学计量比如何,4-甲基-6-三苯甲基苯酚)都形成了双酚盐锌络合物6。得到具有3-叔丁基-2-甲氧基-5-甲基苄氧基的起始基团的配合物4b,并通过X射线衍射法进一步研究其为单体。锌乙基络合物2cZnEt 2和
Zinc complexes supported by multidentate aminophenolate ligands: synthesis, structure and catalysis in ring-opening polymerization of rac-lactide
作者:Liying Wang、Haiyan Ma
DOI:10.1039/c0dt00250j
日期:——
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 efficientlyinitiated 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