Synthesis of mixed-ligand cobalt complexes and their applications in high cis-1,4-selective butadiene polymerization

Abstract

Synthesis of mixed-ligand cobalt complexes and their applications in high cis-1,4-selective butadiene polymerization, Inorganica Chimica Acta (2015), doi: http://dx. AbstractIncomplete oxidation of (N-di-tert-butylphosphino)-6-(2-methyl-2'H-benzoimidazole)-2-aminepyridine dichlorocobalt (PN 3 CoCl 2 ) in DMF results in a unique co-crystal

Dienes Polymerization: Where We Are and What Lies Ahead

“…Highly cis -1,4-polybutadienes (∼95%) were obtained with catalysts based on bidentate phosphine Co complexes (CoCl 2 [R 2 P­(CH 2 ) n PR 2 ]–MAO; R = Me, Et, Ph; n = 1, 2), independently of the type of bidentate phosphine ligand bonded to the cobalt atom. ,, Predominantly cis -1,4-polybutadienes were also recently obtained with several new catalytic systems based on cobalt complexes with bi- and tridentate ligands containing N and/or O as donor atoms (e.g., bis-imines, bis-imino-pyridines, keto-imines, and keto-pyridinimines), regardless of the nature of the ligand coordinated to the cobalt atom. ,,,,− …”

“…Cobalt complexes with 2,6-bis­(imidate)­pyridyl ligands, bis­{[2-(4,5-diphenylimidazolyl)­phenylimino­[phenolate} ligands, 2,6-bis­(dimethyl-2-oxazolin-2-yl)­pyridine ligands, mixed ligands such as N - i - O -butyl­phosphino-6-(2′-methyl­benzoimidazole)-2-aminopyridine, and pyridine–imino ligands with bulky aryl substituents, in combination with MAO or EASC, also gave high cis -1,4-polybutadienes (Figure ).…”

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 .…”

Capability of PN3-type Cobalt Complexes toward Selective (Co-)Polymerization of Myrcene, Butadiene, and Isoprene: Access to Biosourced Polymers

“…In (co)­polymerization of conjugated dienes, a cobalt-based system has unambiguously shown distinguished performances and received the earliest recognition in the academic and commercial production of cis -1,4 and 1,2-polybutadiene due to facile availability, high air and thermal stability of compound. Particularly, the versatility as well as tunable regio and stereoselectivity in polymerization of some substituted butadienes; − for example, the unique 1,2 stereospecificity toward butadiene ,,,,, as well as 3-methyl-1,3-pentadiene, affording semicrystalline to crystalline materials whose properties can be tuned by the catalyst formula as well as polymerization procedures . Nevertheless, cobalt has been less known for catalytic polymerization of isoprene and myrcene, ,, and the reason why subtle monomer difference causes large differences in reactivity and selectivity has not yet been explored.…”