Zirconium complexes of cyclopenta[b]pyridine: synthesis, structure, and olefin polymerization catalysis

摘要

By treatment of CpZrCl_3 with the lithium salt of cyclopenta[b]pyridine (LiCp~(Py)) in toluene, the unsymmetrical complex Cp(eta~5-Cp~(Py))ZrCl_2 was prepared in 32% yield. On the evidence of X-ray crystal structure analysis, the bifunctional Cp~(Py) ligand coordinates Zr in an eta~5-manner rather than via nitrogen. Cyclopenta[b]pyridine turned out to react with Zr(NMe_2)_4 in toluene to form mono-cyclopentadienyl complex (eta~5-Cp~(Py))Zr(NMe_2)_3(Me_2NH) in 70% yield. The polymerization of ethylene and the copolymerization of ethylene with 1-hexene or propene catalyzed by Cp(eta~5-Cp~(Py))ZrCl_2 activated with MAO was studied in detail.