Synthesis of low to high molecular weight poly(1-hexene); rigid/flexible structures in a di- and mononuclear Ni-based catalyst series

1-Hexene was polymerized with mono- (MC n , n = 1–3) and dinuclear (BC n , n = 1–7) α-diimine Ni-based catalysts bearing different backbones, ortho -substituents and spacers between the active centers. Significantly, catalyst BC 2 through an optimum bulkiness in its structure and electronic and steric effects, had the highest activity among all the dinuclear and mononuclear analogues, and made poly(1-hexene) with high M w (1.7 × 10 6 g mol −1 ) and a narrow MWD (2.2). Moreover, a lower level of branching density was observed for the samples obtained by catalysts BC 1 and BC 2 (83–85/1000C) in comparison to MC 1–3 (107–120/1000C) and BC 3–7 (131–150/1000C).