Copolymerization of Ethylene with Conjugated Dienes

Polyolefins, a Success Story

“…The copolymerization of olefins with conjugated dienes was a challenge since these two classes of monomers polymerized via different mechanisms. Neodymium metallocene catalysts showed unprecedented copolymerization of ethylene with butadiene leading to a new class of elastomers [ 108 , 109 , 110 ]. Recently, Perrin et al used computational investigation to demonstrate that a heterobimetallic and a monomeric intermediate were formed after insertion of ethylene and butadiene respectively [ 111 ].…”

Ene/Diene Copolymerization Catalyzed by Cationic Sc and Gd d0 Metal Complexes: Speciation, Ion Pairing, and Selectivity from a Computational Perspective

“…4,5,6 Efficient catalytic systems are mainly based on cobalt, nickel, titanium and neodymium. 4 The latter provide linear polymers with a quasi-regular cis-1,4 content 1,5 whereas cobalt based catalysts yield branched frameworks. 5 Interestingly, it has been shown that rare earth metallocene complexes, when associated to a cationizing agent like [Ph3C][B(C6F5)4] and a cocatalyst such as (AlR3)n or (MgR2)n, yield half-sandwich cationic species that are much more active than neutral ones towards butadiene polymerization.…”

“…5 Interestingly, it has been shown that rare earth metallocene complexes, when associated to a cationizing agent like [Ph3C][B(C6F5)4] and a cocatalyst such as (AlR3)n or (MgR2)n, yield half-sandwich cationic species that are much more active than neutral ones towards butadiene polymerization. 1,3,6 For example, Wakatsuki and coworkers have characterized the cation [(C5Me5)2Ln] + (Ln = Pr, Nd) 7 and have reported the activity of [(C5Me5)2Ln] + (Ln = Pr, Nd, Sm, Gd) towards cis-1,4-butadiene polymerization in the presence of alkylaluminum. 7,8,9 Similarly, Tardif et al have reported the structure of [(2-R-Ind)Ln(N(TMS)2)(L)n] + (Ln = Sc, Gd; L = THF and n = 2, L = PhNMe2 and n = 1) complexes and their activity towards cis-1,4-butadiene polymerization in the presence of alkylaluminum.…”

Identification of a Transient but Key Motif in the Living Coordinative Chain Transfer Cyclocopolymerization of Ethylene with Butadiene

“…The copolymerization of these two classes of monomers is particularly attractive since it provides a wide range of polyolefins bearing unsaturated groups and possibly intra-chain rings. 1 Nevertheless, the copolymerization of olefins with conjugated dienes is a difficult challenge as the copolymerization of these two monomers requires distinct catalysts and polymerization conditions. Indeed, group 4 metallocenes, which are highly active towards olefin polymerization, have shown a dramatic decrease in activity in the presence of butadiene together with a low butadiene insertion.…”

“…Efficient copolymerization catalysts have only recently been developed. 1 Depending on the polymer composition, thermoplastics or elastomers are produced. The microstructure of the inserted butadiene units depends on the regio-and stereo-selectivity of butadiene insertion leading to internal cis or trans double bonds as well as vinyl ramifications.…”