Síntesis, reactividad y aplicaciones catalíticas de complejos [(1-alildimetilsilil) (3[eta]-amidodimetilsilil)]-[eta]5-ciclopentadienilo de metales del grupo 4

Abstract

Since initial studies on scandium catalysts the success of η5- cyclopentadienylsilyl-η1 -amido group 4 metal complexes as efficient catalysts for olefin polymerization has motivated numerous studies and applications.The active species of these homogeneous Ziegler-Natta catalysts is a cationic coordinatively unsaturated 12-electron d0 alkyl compound. Alkene coordination to the metal alkyl cation followed by alkyl migration to the coordinated alkene is the generally accepted mechanism of propagation. Several strategies have been used to stabilize the intermediate cationic (alkylalkene) η5 -ciclopentadienylsilyl-η1 -amido d0 group-4 metal complexes. We have described the formation of catalytically active group 4 metal cationic species stabilized by coordination of the silylallyl olefinic moiety of η5 -ciclopentadienylsilyl-η1-amido and metallocene compounds. Over the past few years there has been a growing interest in developing precatalysts containing only one such group which can be active for olefin polymerization. We have developed the synthesis of new η1- amidosilylmetalocene derivatives, their behaviour in reactions with B(C6F5)3 and as catalysts for olefin polymerization processes. Metal alkyl compounds are convenient models not only for olefin polymerization but also for insertion reactions. We have synthesised and characterised the insertion reactions of isocyanides into metal-alkyl bonds of dialkyl (allylsilyl)(amidosilyl)cyclopentadienyl group 4 metal complexes and C-C coupling reactions of the resulting iminoacyl derivatives.