A new family of zirconocene complexes of the type (Ind)ZrX (where Ind = CMeH and R = Me, Et and Ph) have been synthesised and fully characterised. Six new crystal structures have been reported (-(Ind)ZrBr, -(Ind)ZrCl, -(Ind)Zr(CHPh), -(Ind)Zr(CHPh), -(Ind)ZrBr and -(Ind)Zr(CHPh)). The complexes were studied for slurry-phase ethylene polymerisation when immobilised on solid polymethylaluminoxane (sMAO). Variation in the initiation group was found to have greater influence over polymerisation activity for -catalysts than -catalysts, with -alkyl catalysts showing higher polymerisation activities than -halide. Below 70 °C, polymerisation activity follows the order sMAO--(Ind)Zr(CHPh) sMAO--(Ind)ZrCl and sMAO--(Ind)ZrBr (activities of 657, 561, and 452 kg mol h bar, respectively). sMAO--(Ind)ZrBr produces HDPE with the highest molecular weight, followed by sMAO--(Ind)ZrCl and sMAO--(Ind)Zr(CHPh) ( of 503, 406, and 345 kg mol, respectively, at 50 °C). sMAO--(Ind)ZrBr produced HDPE with almost identical molecular weights to sMAO--(Ind)ZrCl (395 kg mol at 50 °C).
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| http://dx.doi.org/10.1039/d1ra01912k | DOI Listing |
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