Catalysts for the production of polyolefins

摘要

A catalyst precursor of formula (I) or (II) is new: M = Zr or Hf; L = (substd.) cyclopentadienyl ligand; Q = -O-, -NR-, -CR2- or -S-; Y = C or S; Z = -OR, -NR2, -CR3, -SR, -SiR3-, -PR2, or -H provided that when Q is -NR-, the Z is not -CR3; n = 1 or 2; A = univalent anionic gp. when n=2, or divalent anionic gp. when n=1; R = gp. contg. C, Si, N, O and/or P, and R gp(s). may opt. be attached to the L substit; T = bridging gp. comprising 1-10C alkylene or arylene, Ge, Si or alkyl phosphine; and m = 1-7. Also claimed is a catalyst system comprising: (a) the catalyst precursor; and (b) cocatalyst comprising a borate, or a branched or cyclic oligomeric poly(hydrocarbyl aluminium oxide) contg. repeating units of formula (III): -(Al(R')O)- (III) R' = 1-12C alkyl, or aryl e.g. (substd.) phenyl or naphthyl.