Peculiarities of Ethylene Polymerization Reactions with Bis(imino)pyridyl Complexes of CoCl 2 and FeCl 2

The article describes ethylene polymerization reactions with transition metal catalysts based on complexes of CoCl 2 and FeCl 2 with an N,N,N -tridentate ligand 2,6-bis[1-(2,6-dimethylphenylimino)ethyl]pyridine. The complexes are converted into polymerization catalysts by reacting them either with polymethylalumoxane (MAO) or with a combination of Al(C 2 H 5 ) 2 Cl and Mg(C 4 H 9 ) 2 at an [Al]:[Mg] ratio of ~3. Both MAO-activated complexes readily polymerize ethylene at 35 °C with the formation of linear, low molecular weight polymers with a narrow molecular weight distribution. The same complexes, when activated with the Al(C 2 H 5 ) 2 Cl-Mg(C 4 H 9 ) 2 combination, form multi-center catalysts and generate polyethylenes with a broad molecular weight distribution.