Facile, Efficient Copolymerization of Ethylene with Bicyclic, Non‐Conjugated Dienes by Titanium Complexes Bearing Bis(β‐Enaminoketonato) Ligands

Abstract

Abstract Copolymerizations of ethylene with 5‐vinyl‐2‐norbornene or 5‐ethylidene‐2‐norbornene under the action of various titanium complexes bearing bis(β‐enaminoketonato) chelate ligands of the type, [R 1 NC(R 2 )CHC(R 3 )O] 2 TiCl 2 ( 1 , R 1 =Ph, R 2 =CF 3 , R 3 =Ph; 2 , R 1 =C 6 H 4 F‐ p , R 2 =CF 3 , R 3 =Ph; 3 , R 1 =Ph, R 2 =CF 3 , R 3 = t‐ Bu; 4 , R 1 =C 6 H 4 F‐ p , R 2 =CF 3 , R 3 = t‐ Bu; 5 , R 1 =Ph, R 2 =CH 3 , R 3 =CF 3 ; 6 , R 1 =C 6 H 4 F‐ p , R 2 =CH 3 , R 3 =CF 3 ), have been shown to occur with the regioselective insertion of the endocyclic double bond of the monomer into the copolymer chain, leaving the exocyclic vinyl double bond as a pendant unsaturation. The ligand modification strongly affects the copolymerization behaviour. High catalytic activities and efficient co‐monomer incorporation can be easily obtained by optimizing the catalyst structures and polymerization conditions.