Ethylene/butadiene copolymerization can be performed by neodymocene catalysts in the presence of an alkylating/chain transfer agent. A variety of polymerization activities and copolymer microstructures can be obtained depending on the neodymocene ligands. For a set of four catalysts, namely (C5Me5)2NdR, [Me2Si­(3-Me3SiC5H3)2]­NdR, [Me2Si­(C5H4)­(C13H8)]­NdR and [Me2Si­(C13H8)2]­NdR, we report a DFT mechanistic study of this copolymerization reaction performed in the presence of dialkylmagnesium. Based on the modeling strategy developed for the ethylene homopolymerization catalyzed by (C5Me5)2NdR in the presence of MgR2, our model is able to account for the following: (i) the formation of Nd/Mg heterobimetallic complexes as intermediates, (ii) the overall differential activity of the catalysts, (iii) the copolymerization reactivity indexes, and (iv) the specific microstructure of the resulting copolymers, including branching and cyclization. The analysis of the reaction mechanisms and the energy profiles thus relates ligand structure, catalyst activity, and polymer microstructure and sets the basis for further catalyst developments.

Fluorinated activating supports (AS) for metallocene complexes were prepared via treatment of silica with AlEt3 or AlEt2F followed by pyrolysis and combustion steps, and a subsequent fluorination step when AlEt3 was used. This new family of activators appears to be universal for metallocene complexes leading to catalysts displaying high activities in ethylene polymerization without the addition of MAO. A productivity of 3200 g gAS –1 was obtained in 1 h with the catalyst rac-Et(Ind)2ZrCl2/AS8/Al(iBu)3 at 80 °C under 10 bar of ethylene. An isotactic polypropylene with a melting transition at 145 °C was prepared using rac-Me2Si(2-Me-benz(e)Ind)2ZrCl2 activated by AS9 and Al(iBu)3. The spherical particle morphology of polyolefins was particularly adapted to slurry processes employed in industry.