Polymerization of butadiene and isoprene using α-diimine cobalt catalysts bearing electron donor at the N-aryl of imine

Catalytic Behavior of Cobalt Complexes Bearing Pyridine–Oxime Ligands in Isoprene Polymerization

“…And, complete conversion of isoprene could be achieved even though the [Co]/[AlEt 2 Cl] is changed to 1/10 (entry 2, Table 2), which is virtually irrelevant to cocatalyst feeding, suggestive of the conformation stability of active species. It should be pointed out that this catalytic system showed extremely high activity (8.16 × 10 5 g (mol of Co) −1 (h) −1 ), which is comparable with the recent work on rigid Co(II) chloride catalysts (1.37 × 10 5 g (mol of Co) −1 (h) −1 ) [68] and α-diimine cobalt catalysts (0.54 × 10 5 g (mol of Co) −1 (h) −1 ) [58]. All resultant polyisoprenes are predominantly cis-1,4 enchained with about 30% of 3,4 units.…”

“…The kinetic studies reveal that the catalyst systems follow a typical living mechanism [46]. Meanwhile, N,N-containing bidentate ligands, such as iminopyridine and α-diimine, have also been tested for cobalt-catalyzed polymerization, and attracted extensive investigations in the past few years [49][50][51][52][53][54][55][56][57][58]. For example, Sun and coworkers reported a series of (8-(arylimino)-5,6,7-trihydroquinolin-2-yl)methyl acetate (N,N) ligated cobalt complexes and applied them in isoprene polymerization.…”

“…Due to our ongoing burning desire to develop polymerization catalysts with high performance, we are interested in transition metal catalysts coordinating with N,N-bidentate ligands for diene polymerization [58][59][60][61][62][63][64]. In a recent piece of work, we reported that the pyridine-oxime ligand exhibited high performance in iron catalyzed isoprene polymerization with very low amount of methylaluminoxane [65].…”