Alternating ethylene-norbornene copolymerization catalyzed by cationic organopalladium complexes bearing hemilabile bidentate ligands of alpha-amino-pyridines.

Cationic methylpalladium complexes with hemilabile bidentate ligands of alpha-amino-pyridines, in the form of {[R(1)HNCR(2)H(o-C(6)H(5)N)]Pd(Me)(NCMe)}(BF(4)) (R(1) = (i)Pr, (t)Bu, Ar R(2) = H, Me) have been found to be effective precursors for catalytic copolymerization of ethylene and norbornene under mild conditions. The copolymer products exhibit predominant alternating microstructures which are evidenced by NMR and mass spectrometry as well as a kinetic analysis according to the Finman-Ross relationship.