Zirconadihydrophosphetes as highly active species for ethylene polymerization

The zirconadihydrophosphetes showed high activities for ethylene polymerization as well as copolymerization with α-olefins or norbornene in the presence of methylaluminoxane (MAO) as cocatalyst. The alkylated intermediates as the active species were confirmed by NMR measurement. The cause for their high catalytic activities is assumed to the disassociation and coordination of the ethylene-bridged phosphine to the zirconium species. A plausible mechanism for the polymerization is proposed.

A series of zirconoalkenylphosphines were synthesized as the highly active catalysts for ethylene polymerization and copolymerization with α-olefins or norbornene in presence of MAO. The possible mechanism in polymerization was provided according to ethylene activation experiment and data from 1H, 13C and 31P NMR.Figure optionsDownload as PowerPoint slide