Metal dependent control of cis-/trans-1,4 regioselectivity in 1,3-butadiene polymerization catalyzed by transition metal complexes supported by 2,6-bis[1-(iminophenyl)ethyl]pyridine

Iminoimidazole‐based Co(II) and Fe(II) complexes: Syntheses, characterization, and catalytic behaviors for isoprene polymerization

“…Diverse ancillary ligands, such as N^N^N, N^N^O, N^C^N, N^N, O^P architectures were designed and synthesized. The corresponding Co(II) and Fe(II) complexes were further employed in (co‐)polymerization of dienes . Very recently, Huang and other groups reported Co(II) complexes for isoprene polymerization that offer high activity, precise control over the molecular weight and high cis ‐1,4‐alt‐3,4 microstructures .…”

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

“…Ligand was synthesized by our reported method [59]. NMR analyses of ligands and polymers were performed on a Bruker spectrometer, and the microstructures of polybutadiene were calculated by our reported methods [48]. .…”

“…This finding has also intrigued us to investigate the catalytic performance in conjugated diene polymerization and allowed access to various microstructural controlled polybutadienes. The catalyst structure-polymer microstructure relationships show distinctive monomer coordination and insertion modes are operated [48]. In persuit of efficient catalyst, we also have developed classes of NNN [23] and NNP [42][43][44][45] pyridine transition metal olefin and conjugated diene catalysts which have straightforward transformed butadiene to generation of polybutadiene with desired structures.…”

Polymerization of 1,3-butadiene catalyzed by ion-pair cobalt complexes with (benzimidazolyl)pyridine alcohol ligands

“…Similar to the neutral cobalt-based catalysts [26,28,31,34,37], the butadiene polymerization behavior with the current ion-pair cobalt complex C1/EASC catalytic system was very sensitive to reaction temperature. The 39.3% conversion of butadiene was gained at 0 • C; however, some cobalt-based catalytic systems gave almost no activity at 0 • C [28,29,34]. The complete conversion of butadiene was observed at both 30 • C and 50 • C. The 89.4% conversion of butadiene was obtained at 70 • C, suggesting the good thermal stability of this catalytic system.…”

“…More recently, research efforts have been made on the design of welldefined and highly active cobalt complexes ligated by bi-, trior multi-dentate organic ligands. For example, (salen)cobalt(II) [( − ONNO − )Co] [25] and bis(salicylaldiminate)cobalt(II) complexes [(NO − ) 2 Co] [26], dinuclear cobalt(II) complexes with 3-aryliminomethyl-2-hydroxybenzaldehyde ligands [( -L) 2 Co 2 ( -OAc) 2 ] [27], cobalt dichloride complexes bearing neutral tridentate ligands [(NNN)CoCl 2 ] [28][29][30][31][32][33][34][35][36] (such as 2,6-bis(imino)pyridine, bis(benzimidazolyl)amine, 2,6-bis(benzimidazolyl)pyridine or 2,6-bis(pyrazol)pyridine ligands) have achieved high activity and high cis-1,4 selectivity in the polymerization of butadiene in combination with MAO, MMAO or ethylaluminum sesquichloride (EASC).…”