Ethylene homopolymerization and ethylene/1-hexene copolymerization catalysed by mixed salicylaldiminato cyclopentadienyl zirconium complexes

Three new mixed salicylaldiminato cyclopentadienyl zirconium complexes Cp′[2-But-6-(C6H11NCH)C6H3O]ZrCl2 (Cp′ = nBuC5H4 (3a), tBuC5H4 (3b) and Me4C5H (3c)) were prepared and the structure of complex 3c was confirmed by X-ray diffraction analysis. All of the three complexes showed high activities for ethylene homopolymerization with the activation of methylaluminoxane, and 3a showed the highest activity up to 1.15 × 106 g PE/mol Zr h for ethylene homopolymerization at 70 °C. The 13C NMR spectrum showed that the obtained polymer is linear polyethylene. Complexes 3a–c also catalysed ethylene/1-hexene copolymerization with high activities from 6.29 × 105 to 12.3 × 105 g Copolymer/mol Zr h and with 0.89–1.39% 1-hexene incorporation level. In addition, the influence of the substituted alkyl on Cp on the catalytic behavior of corresponding zirconium complexes was discussed.