Catalytic 1,3-Cyclohexadiene Homopolymerization and Regioselective Copolymerization with Ethylene

1,3-Cyclohexadiene (CHD) was homo- and copolymerized by means of diimine nickel complexes and various substituted titanium based half-sandwich complexes activated with methylaluminoxane (MAO). Soluble polycyclohexadienes were produced with the constrained geometry catalyst [Me 2 Si(N t Bu)(Me 4 Cp)]TiCl 2 (CBT) (Cp = cyclopentadienyl, Me = methyl). Only in the presence of CBT/MAO soluble high molecular weight CHD copolymers with ethylene were obtained. The CHD incorporation was varied between 0 and 12.3 mol-%. According to NMR analysis the CHD/ ethylene copolymerization is highly regioselective, accounting for exclusive formation of 1,4-cyclohexene units randomly distributed in the polyethylene backbone.