Lanthanidocene Catalysts for the Homo- and Copolymerization of Ethylene with Butadiene

Alkylation of lanthanidocene chloride complexes was performed with BuLi, Mg(Bu)(Oct), or an equimolar mixture of BuLi and AlH(iBu)2. In the case of the latter, chain transfer reactions were observed between neodymium and aluminium, and higher activities were obtained. The use of the silylene‐bridged complex, [Me2Si(3‐Me3SiC5H3)2]NdCl, in combination with BuLi and AlH(iBu)2 provided an efficient and unique catalyst for the copolymerization of ethylene with butadiene. Copolymers with high butadiene contents (up to 62 mol‐%) were synthesized. The microstructure of butadiene units was mostly trans‐1,4, and copolymers exhibited a strong alternating character. The influence of butadiene content on the thermal properties of the copolymers was also investigated. Copolymerization of ethylene with butadiene using 4/BuLi/AlH(iBu)2 (▪) and 2/BuLi/AlH(iBu)2 (▴).