CATIONIC ALKYL ALUMINUM ETHYLENE POLYMERIZATION CATALYSTS BASED ON MONOANIONIC N,N,N-PYRIDYLIMINOAMIDE LIGANDS

Treatment of the 2,6-bis(imino)pyridines {[2,6-(ArNCR)(2)C5H3N]} [R = H, Ar = 2,6-i-Pr2C6H3 or 2,4,6-Me3C6H2; R = Me, Ar = 2,6-i-Pr2C6H3] wi th AlMe3 at elevated temperature gives, via migration of a methyl grou p to the ligand backbone, the pseudo-five coordinate dimethylaluminium species {2-[ArNCR(Me)],6-(ArNCR)C5H3N}-AlMe2 (1a-c); upon treatment w ith B(C6F5)(3), 1a-c cleanly afford the cationic methyl complexes rNCR (Me)],6-(ArNCR)C5H3N}AlMe](+)[MeB(C6F5)(3)](-) (2a-c) which are active for ethylene polymerization.