Hydrosilylation in the Design and Functionalization of ansa-Metallocene Olefin Polymerization Catalysts

Abstract

The group 4 ansa-metallocene complexes [M{Me(H)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr, Hf),that contain a Si-H bond, have been used as hydrosilylation reagents with the silane substrates, Si(CH=CH2)4 and Me2Si(CH=CH2)2. Our results show that the hydrosilylation reaction takes place at only one of the vinyl groups to give [M{(CH2=CH)3SiCH2CH2(Me)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr, Hf) and [M{(CH2=CH)Me2SiCH2CH2(Me)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr, Hf). Hydrosilylation of the remaining vinyl groups can be achieved by using simple silane reagents, for example, HSiEt3 to give [M{(Et3SiCH2CH2)3SiCH2CH2(Me)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr) and [M{(Et3SiCH2CH2)Me2SiCH2CH2(Me)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr).

All the compounds have been tested as homogeneous catalysts in the polymerization of ethylene and propylene