几个钛异丙醇盐1 - 8已经制备的Ti的反应(O-我-Pr)4与一系列对应的四齿萨兰型[ONNO]配体与桥接氮原子的苄基或甲基的取代基。它们的特征在于1 H NMR,13 C { 1 H} NMR和元素分析。化合物的固态结构2,4,6,和7已通过X射线晶体学确定。X射线衍射分析和11 H NMR证实这些钛络合物都是在固态和溶液结构中具有六配位中心钛的单体种类。复合物2,4,6,和8与桥接氮的取代基的苄基,得到PLA与分子量大于化合物高1,3,5,和7与甲基取代基一样。
Comparative study of ring-opening polymerization of <scp>l</scp>-lactide and ε-caprolactone using zirconium hexadentate bis(aminophenolate) complexes as catalysts
complexes as catalysts for the ring opening polymerization of L-lactide (LA) and ε-caprolactone (CL) were investigated. Ligands bearing various chelating groups have a profound influence on the catalysis results. Among them, the thiophen-2-yl methyl group showed the greatest activity while the pyridine-2-yl methyl group showed the worst performance with regard to the rate of CL polymerization. However
研究了一系列的双(氨基酚酸)锆配合物,用于L-丙交酯(LA)和ε-己内酯(CL)的开环聚合。带有各种螯合基团的配体对催化结果有深远的影响。其中,就CL聚合速度而言,噻吩-2-基甲基表现出最大的活性,而吡啶-2-基甲基表现出最差的性能。然而,LA聚合速率的趋势相反。动力学结果表明对[CL]和[LA]具有一阶依赖性。但是,催化剂浓度的顺序不同。聚合反应依赖于[ L OMe Zr(OBn)2CL的],但对LA的[ L OMe Zr(OBn)2 ]具有一阶依赖性。
Remarkable Stereocontrol in the Polymerization of Racemic Lactide Using Aluminum Initiators Supported by Tetradentate Aminophenoxide Ligands
作者:Pimpa Hormnirun、Edward L. Marshall、Vernon C. Gibson、Andrew J. P. White、David J. Williams
DOI:10.1021/ja038757o
日期:2004.3.1
A new family of aluminum complexes bearing tetradentate bis(aminophenoxide) ligands is reported and shown to initiate the living ring-openingpolymerization of rac-lactide. The microstructures of the polylactide products are found to be highly dependent upon the ancillary ligand substituents, ranging from highly isotactic (Pm = 0.79) to very highly heterotactic (Pr = 0.96).
Titanium complexes containing new dianionic tetradentate [ONNO]-type ligands with benzyl substituents on bridging nitrogen atoms: Syntheses, X-ray structures, and catalytic activities in ring opening polymerization of lactide
作者:So Han Kim、Junseong Lee、Da Jung Kim、Jung Hee Moon、Sungwoo Yoon、Hyung Jin Oh、Youngkyu Do、Young Soo Ko、Jin-Heong Yim、Youngjo Kim
DOI:10.1016/j.jorganchem.2009.06.037
日期:2009.10
isopropoxides 1–8 have been prepared by the reaction of Ti(O-i-Pr)4 with a series of corresponding tetradentate Salan-type [ONNO] ligands with benzyl or methyl substituents on bridging nitrogen atoms. They have been characterized by 1H NMR, 13C1H} NMR, and elemental analysis. Solid state structures of compounds 2, 4, 6, and 7 have been determined by X-ray crystallography. X-ray diffraction analysis
几个钛异丙醇盐1 - 8已经制备的Ti的反应(O-我-Pr)4与一系列对应的四齿萨兰型[ONNO]配体与桥接氮原子的苄基或甲基的取代基。它们的特征在于1 H NMR,13 C 1 H} NMR和元素分析。化合物的固态结构2,4,6,和7已通过X射线晶体学确定。X射线衍射分析和11 H NMR证实这些钛络合物都是在固态和溶液结构中具有六配位中心钛的单体种类。复合物2,4,6,和8与桥接氮的取代基的苄基,得到PLA与分子量大于化合物高1,3,5,和7与甲基取代基一样。
Single-step synthesis of salans and substituted salans by Mannich condensation
作者:Edit Y Tshuva、Natalie Gendeziuk、Moshe Kol
DOI:10.1016/s0040-4039(01)01264-3
日期:2001.9
A convenient route for the synthesis of a variety of salan-type compounds is introduced. The synthesis is based on a single-step Mannichcondensation between readily available starting materials: primary or secondary amines, formaldehyde and substituted phenols. This methodology is suitable for the preparation of chiral salans as well, which may find applications in asymmetric catalysis.
Poly(3-hydroxybutyrate) (PHB) is a material produced naturally by bacteria but is also chemically accessible via ring-openingpolymerization (ROP) of β-butyrolactone (β-BL). In ROP, catalyst design plays a key role in the production of PHB with different stereomicrostructures, i.e., syndiotactic, isotactic, or atactic PHB. In this work, we demonstrate a simple procedure for generating the catalysts
聚(3-羟基丁酸酯)(PHB) 是一种由细菌自然产生的材料,但也可以通过 β-丁内酯 (β-BL) 的开环聚合 (ROP) 化学获得。在 ROP 中,催化剂设计在生产具有不同立构微观结构(即间规、等规或无规 PHB)的 PHB 中起着关键作用。在这项工作中,我们展示了一个简单的程序,通过将合适的钇前体与相应的 salan 前配体方便地结合起来,就地生成催化剂。这种方法避免了催化剂的精细分离,并能够高通量筛选用于 β-BL ROP 的钇 salan 催化剂库。可以确定配体框架对催化剂的立体选择性和活性的电子和空间影响以及限制,并建立了结构-性质关系。根据取代模式,这些原位生成的催化剂产生了具有高活性的间规富集、全同立构富集或无规立构 PHB。