| 摘要 |
Addition polymerization catalysts of the formula L l MX<+> A<-> prepared by oxidation of a Group 4 or Lanthanide metal derivative of the formula L l MX2 with an oxidizing agent of the formula (Ox<+a>)b(A<->)d are free of interfering amine byproducts. In these formulae:- L independently each occurrence is a ligand or ligand system, especially a eta <5>-cyclopentadienyl group optionally covalently bonded to M through a substituent; l is an integer, especially 1; M is a Group 4 or Lanthanide metal, especially titanium or zirconium; X is a hydride or a hydrocarbyl, silyl or germyl group having up to 20 carbon, silicon or germanium atoms, especially benzyl; A<-> is a monovalent compatible noncoordinating anion, especially perfluorotetraphenyl borate; Ox<-a> is a cationic oxidizer having a charge (+a), especially Ag<+> or ferrocenium; A- is a compatible noncoordinating anion; and b and d are integers selected to provide charge balance. |
