Synthesis, characterization and butadiene polymerization studies of cobalt(II) complexes bearing bisiminopyridine ligand

Tunable regioselectivity in 1,3-butadiene polymerization by using 2,6-bis(dimethyl-2-oxazolin-2-yl)pyridine incorporated transition metal (Cr, Fe and Co) catalysts

“…They have an identical molecular structure with three coordinated nitrogen atoms and three coordinated chlorides, and the geometry at the metal center is a little distorted from the typical octahedral geometry. The whole molecule displays C 2v symmetry about the equatorial plane with the other two nitrogens situated on the ends of the bent axis, in consistent with the decribed six coordinated iron and chromium complexes [22,23]. As seen from the crystal structure, is generally less than the other metal-chloride bonds, while the bond value of Cr-Cl2 These subtle structures may affect their catalytic performance by influencing the monomer orientation, coordination mode, insertion into the growing polymer as well as the interconversion of syn-ally between anti-ally intermediate isomers.…”

“…In this respect, there has been increasing interests in the applications of N-O [21,[34][35], SOOS [31], P-P [36][37][38], and pincer ligand N,N,X (X = N, P and C) [22,23,[39][40][41] covering over a broad range of catalytic reactions, in particular, catalyzing diene with polar monomers, as such straightforwards access to a new family of functional rubber materials.…”

Pyridine–oxazoline and quinoline–oxazoline ligated cobalt complexes: Synthesis, characterization, and 1,3-butadiene polymerization behaviors

“…For example, (salen)cobalt(II) [25] and bis(salicylaldiminate) cobalt(II) [26] were reported to be highly active for cis-1,4 polymerization of 1,3-butadiene. Cobalt dichloride complexes bearing various tridentate ligands such as 2,6-bis(imino)pyridine [6,27], 2,6-bis(pyrazol)pyridine [28], bis(N-arylcarboximidoylchloride)pyridine [29], 2-arylimino-6-(alcohol) pyridine/2-arylamino-6-(alcohol) pyridine [30], and 3-aryliminomethyl-2-hydroxybenzaldehyde [31] afforded cis-1,4 polybutadienes in high yields.…”

Cobalt and nickel complexes supported by 2,6-bis(imidate)pyridyl ligands: Synthesis, characterization, and 1,3-butadiene polymerization studies

“…Recently, such complexes are also studied in 1,3-butdiene polymerization [28][29][30][31][32] . We recently reported that Co(II) complexes bearing bis(imino)pyridine 33 and α-diimine 34 ligands exhibited high catalytic activity and cis-1,4-selectivity for 1,3-butadiene polymerization, and quite interestingly, the addition of phosphines to these systems not only enhanced the catalytic activity but also switched the selectivity from cis-1,4-to 1,2-manner. 35 In these our previous reports, it was found that, for Gibson-type catalysts, the substituents on the C=N carbon position showed a large influence on the catalytic behaviors of the corresponding Co(II) complexes 36 .…”