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首页> 外文期刊>Coordination chemistry reviews >Group 4 ketimide complexes: Synthesis, reactivity and catalytic applications
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Group 4 ketimide complexes: Synthesis, reactivity and catalytic applications

机译：第4组酮亚胺配合物：合成，反应性和催化应用

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摘要

The synthesis and reactivity of Group 4 ketimide complexes, comprising bent-metallocene, half-sandwich and cyclopentadienyl-free compounds is described. Neutral compounds of general formulas Cp'_2M(N=CR~1R~2)X and Cp'_2M(N=CR~1R~2) have been prepared by transmetallation reac-tions of metal halide derivatives with appropriate lithium, tin or silicon ketimide derivatives and by acid-base reactions between ketimines and anionic ligands attached to the metals. Ti(Ⅲ) and cationic M(Ⅳ) bent-metallocene complexes have been mainly prepared by nitrile insertion into metal-carbon or metal-hydride bonds of bis-Cp systems. Metallacyclic ketimide complexes are also described. These were obtained as a result of oxidative addition reactions, nitrile insertions and nitrile additions to unsaturated C-C bonds in bent-metallocene systems. Half-sandwich and cyclopentadienyl-free complexes were prepared aiming at the synthesis of olefin polymerization catalyst precursors through transmetallation reactions. Titanium systems containing one Cp ring and one ketimide ligand in particular have proven to be highly active ethylene, propylene and l-hexene homopolymerization catalysts when activated by MAO. The activities reported in styrene homopolymerization are slightly lower although CpTi(N=C~tBu_2)Cl_2 catalyses living styrene/ethylene copolymerization. This emerging role of ketimide ligands as ancillary ligandsin the reactivity of early transition metals is quite recent and comes from their inertness towards insertion of unsaturated substrates in M—N bonds and electrophile attack.
机译：描述了包含弯曲金属茂，半三明治和不含环戊二烯基化合物的第4组酮亚胺配合物的合成和反应性。通式Cp'_2M（N = CR〜1R〜2）X和Cp'_2M（N = CR〜1R〜2）的中性化合物是通过金属卤化物衍生物与适当的锂，锡或硅进行金属转移反应制得的酮衍生物和酮亚胺与附着在金属上的阴离子配体之间的酸碱反应。 Ti（Ⅲ）和阳离子M（Ⅳ）弯茂金属配合物主要是通过将腈插入bis-Cp体系的金属-碳或金属氢化物键中而制备的。还描述了金属环酮亚胺化物配合物。这些是通过在弯曲金属茂系统中进行氧化加成反应，腈插入和腈加成至不饱和C-C键的结果而获得的。制备了半三明治和不含环戊二烯基的配合物，旨在通过金属转移反应合成烯烃聚合催化剂前体。当由MAO活化时，特别是含有一个Cp环和一个酮亚胺配体的钛体系已被证明是高活性的乙烯，丙烯和1-己烯均聚催化剂。尽管CpTi（N = C〜tBu_2）Cl_2催化活性苯乙烯/乙烯共聚，但在苯乙烯均聚中报道的活性稍低。酮亚胺基配体作为辅助配体在早期过渡金属反应中的这种新兴作用是最近才出现的，这是由于它们对不饱和底物插入MN键和亲电试剂的惰性所致。

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