Synthesis And Application Of Fe,Ni And Pd Complexes Possessing Bis (Imidazolin-2-imino)pyridine Ligand For Olefin Polymerization

In this study,we synthesized three new Fe,Ni and Pd complexs supported by bis?imidazolin-2-imino?pyridine ligand.The ligand was characterized by ¹H NMR and the molecular structure of these complexes were determined by X-ray single crystal diffraction.The Fe complex shows high activity for ethylene polymerization using modified methyaluminoxane?MMAO?as a cocatalyst in toluene.Ni complex shows high activity for norbornene polymerization using modified methyaluminoxane?MMAO?or methyaluminoxane?MAO?as a cocatalyst.Pd complex did not show activity for norbornene and ethylene polymerization using Na BAF?Sodium tetrakis[3,5-bis?trifluoromethyl?phenyl]borate?as a cocatalyst.?1?X-ray single crystal diffraction of 2,6-bis[?1,3-di-tert-butylimidazolin-2-imino?-methyl]pyridineine·Iron?II?chloride complex shows unexcepted result that iron atom coordinated with two nitrogen atoms rather than three nitrogen atoms.After activation of the iron complex with modified methylaluminoxane?MMAO?,the iron catalyst showed high activity up to 1.68×10⁷ g PE·mol^-1·h^-1 for ethylene polymerization,and produced high molecular weight(Mw = 430 kg·mol^-1)linear polyethylenes.The polymerization system still shows high activity at high temperature indicating good thermal stability of this catalyst probably due to the bulk substitute of imidazolin group.?2?X-ray single crystal diffraction of 2,6-bis[?1,3-di-tert-butylimidazolin-2-imino?-methyl]pyridineine·nickel?II?bromide complex shows that nickel atom coordinated with three nitrogen atoms,and one of the bromine atom drop out from metal atom.After activation of the nickle complex with MMAO,the catalytic system showed high activity up to 1.46×10⁷ g·mol^-1·h^-1 for norbornene polymerization,and produced high molecular weight(Mn = 1540 kg·mol^-1)polynorbornen.After activation of the nickle complex with MAO,the catalytic system showed high activity up to 2.55×10⁷ g·mol^-1·h^-1 for norbornene polymerization and produced high molecular weight(Mn = 520 kg·mol^-1)polynorbornene.However,after activation of the nickle complex with MMAO/MAO,the catalytic system showed very weak activity for ethylene polymerization.?3?X-ray single crystal diffraction of 2,6-bis[?1,3-di-tert-butylimidazolin-2-imino?-methyl]pyridineine·Chloro methylpalladium?II?complex shows that palladium atom coordinated with three nitrogen atoms and chlorine atom drop out from metal atom.After activation of the palladium complex with Na BAF?Sodium tetrakis[3,5-bis?trifluoromethyl?phenyl]borate?,the catalytic system showed no activity for ethylene and norbornene polymerization.