Polymerization of ethylene with nickel α‐diimine catalysts

Several nickel α-diimine compounds of the general formula (ArN=C(R)-C(R)=NAr)NiX 2 (Ar= 2,6-alkyl substituted Ph, R= H or CH3, X= Br or CH 3 ) were tested in ethylene polymerization after activation with different cocatalysts such as methylaluminoxane, AlEt 2 Cl or other aluminium alkyls, and ionizing reagents like B(C 6 F 5 ) 3 , [CPh 3 ][B(C 6 F 5 ) 4 ] or HBF 4 . The performances of different catalytic systems werre compared with refennce to polymer productivity and structure. The degree of branching of the obtained polymers was shown to depend not only on the ligand environment at the Ni centre but also on the type of cocatalyst