Titanium and zirconium complexes with non-salicylaldimine-type imine-phenoxy chelate ligands: syntheses, structures, and ethylene-polymerization behavior.
Titanium and zirconium complexes with non-salicylaldimine-type imine-phenoxy chelate ligands: syntheses, structures, and ethylene-polymerization behavior.
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DOI：
10.1002/asia.200600256
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发表时间：
2006-12
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影响因子：
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通讯作者：
Yasuhiko Suzuki;Hidetsugu Tanaka;T. Oshiki;K. Takai;T. Fujita
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文献类型：
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作者：
Yasuhiko Suzuki;Hidetsugu Tanaka;T. Oshiki;K. Takai;T. Fujita
合成了新型含亚胺-苯氧基螯合配体的钛、锆配合物[{2，4-di-tBu-6-（RCH=N）-C6 H4 O} 2 MCl 2]（1：M = Ti，R = Ph; 2：M = Ti，R = C6 F5; 3：M = Zr，R = Ph; 4：M = Zr，R = C6 F5），并研究了其作为乙烯聚合预催化剂的性能。1H NMR光谱表明，这些配合物作为结构异构体的混合物存在。X-射线晶体学分析的加合物1HCl表明，它存在作为一个两性离子复合物，其中H和Cl是位于靠近一个亚胺氮原子和中心金属，分别。X-射线分子结构还表明，一个亚胺苯氧基与顺式C=N构型的功能作为一个双齿配体，而另一个，反C=N的形式，作为一个单齿苯氧基配体。虽然Zr与甲基铝氧烷（MAO）或[Ph 3C]+ [B（C6 F5）4]-/AliBu 3的配合物3和4显示出中等活性，但Ti同系物1和2与适当的活化剂结合，以高效率催化乙烯聚合。在25 ℃下用MAO活化后，2显示出非常高的活性，为19900（kg PE）（mol Ti）（-1）h（-1），这与[Cp 2 TiCl 2]和[Cp 2 ZrCl 2]的活性相当，尽管提高聚合温度确实导致活性显著降低。配合物2含有C6 F5基团的亚胺氮原子和介导的非活性型聚合，不像相应的水杨醛亚胺型配合物。相反，在[Ph 3C]+ [B（C6 F5）4]-/AliBu 3活化的情况下，随着温度升高（25-75 ℃），1表现出增强的活性，并在75 ℃下保持非常高的活性60分钟（18740（kg PE）（mol Ti）（-1）h（-1））。反应的1H NMR光谱研究表明，这种热稳定的催化剂体系产生胺-苯氧基络合物作为催化活性物质。1/[Ph_3C]+ [B（C_6F_5）_4]-/AliBu_3和2/MAO的复合催化剂也可作为高活性的乙烯和丙烯共聚催化剂。
New Ti and Zr complexes that bear imine-phenoxy chelate ligands, [{2,4-di-tBu-6-(RCH=N)-C6H4O}2MCl2] (1: M = Ti, R = Ph; 2: M = Ti, R = C6F5; 3: M = Zr, R = Ph; 4: M = Zr, R = C6F5), were synthesized and investigated as precatalysts for ethylene polymerization. 1H NMR spectroscopy suggests that these complexes exist as mixtures of structural isomers. X-ray crystallographic analysis of the adduct 1HCl reveals that it exists as a zwitterionic complex in which H and Cl are situated in close proximity to one of the imine nitrogen atoms and the central metal, respectively. The X-ray molecular structure also indicates that one imine phenoxy group with the syn C=N configuration functions as a bidentate ligand, whereas the other, of the anti C=N form, acts as a monodentate phenoxy ligand. Although Zr complexes 3 and 4 with methylaluminoxane (MAO) or [Ph3C]+ [B(C6F5)4]-/AliBu3 displayed moderate activity, the Ti congeners 1 and 2, in association with an appropriate activator, catalyzed ethylene polymerization with high efficiency. Upon activation with MAO at 25 degrees C, 2 displayed a very high activity of 19900 (kg PE) (mol Ti)(-1) h(-1), which is comparable to that for [Cp2TiCl2] and [Cp2ZrCl2], although increasing the polymerization temperature did result in a marked decrease in activity. Complex 2 contains a C6F5 group on the imine nitrogen atom and mediated nonliving-type polymerization, unlike the corresponding salicylaldimine-type complex. Conversely, with [Ph3C]+ [B(C6F5)4]-/AliBu3 activation, 1 exhibited enhanced activity as the temperature was increased (25-75 degrees C) and maintained very high activity for 60 min at 75 degrees C (18740 (kg PE) (mol Ti)(-1) h(-1)). 1H NMR spectroscopic studies of the reaction suggest that this thermally robust catalyst system generates an amine-phenoxy complex as the catalytically active species. The combinations 1/[Ph3C]+ [B(C6F5)4]-/AliBu3 and 2/MAO also worked as high-activity catalysts for the copolymerization of ethylene and propylene.