Bis(imino)pyridyl iron and cobalt complexes: the effect of nitrogen substitutents on ethylene oligomerisation and polymerisation

摘要

The synthesis and characterisation of 2,6-bis(imino)pyridyl iron and cobalt complexes [(2,6-(RN-CMe)_2C_5H_3N)-MCl_2] containing nitrogen sulstituents of the R = NPh_2, NPhMe, NMe_2 or 2,5-dimethylpyrrolyl are decribed. These complexes, in combination with the co-catalyst MAO, give catalysts for the oligomerisation or polymerisation of ethylene. The catalytic activity is strongly affected by the substituents R and the polymerisation conditions used. The polymer properties are also a functionof the R substitutents. With R = NPhMe or NMe_2, toluene soluble #alpha#-olefins are obtained, whereas the bulkier substitutents (R = NPh_2 or 2,5-dimethylpyrrolyl) give low molecular weight solid polyethylene