A Density Functional Study of Nickel(II) Diimide Catalyzed Polymerization of Ethylene

摘要: We have applied a nonlocal density functional method to the study of ethylene polymerization with Ni(II) catalytic center coordinated diimine (HNCH−CHNH). investigated chain initialization, propagation, as well isomerization and termination. Chain initialization proceeds in stepwise fashion, an overall activation barrier 11.1 kcal/mol. propagation can proceed via two different pathways, which similar energies (16.8 17.5 kcal/mol, respectively). In contrast behavior observed for metallocene catalysts, none insertion transition states show agostic stabilization. The energy is 12.8 concerted mechanism, rotating simultaneously abstracting β-agostic hydrogen. termination occurs stable hydride intermediate, formed 9.7 kcal/mol decays into product small 1.7 kcal/mol...