Ultrahigh activity and broad temperature resistance of amine–imine cobalt precatalysts for butadiene polymerization

Abstract

A series of amine-imine cobalt complexes (Co1−Co7) has been prepared and characterized. The complexes Co3, Co4, Co6 revealed a distorted tetrahedral geometry by single crystal X-ray diffraction. In the presence...

Isoprene polymerization catalyzed by iron (II) and cobalt(II) complexes carrying 2,6‐bis(1H′‐allylbenzimidazolyl)pyridyl ligand

“…Cobalt catalyst shows to be amenable to polymerization activated with MAO, affording high molecular weight polyisoprene with activities rivaling one of the highest performances ever found. 10,11,[22][23][24][25] High amount of polymer can be recovered for all instances as exemplified from entries 1 to 4 in Table 2. The 1 H NMR for polyisoprene depicted in Figure 2 reveals that the integral centered at 5.4 and 4.9 ppm diagnostic for cis-1,4 and 3.4 units, respectively, are estimated to be 64.9% and 35.1% for polymer obtained from entry 1, Table 2.…”

“…10 Amine-imines ligand supported cobalt catalysts (D) are also efficient to produce polybutadiene with 94.5% 1,4 content. 11 Porri group reported a 2,2 0 -bipyridine supported diethyl iron complex (E), which shows 3,4-syndiotactic stereospecificity activated by MAO. 12,13 Ricci et al described an iron catalyst carrying a bipyridine ligand (E) is able to produce 67%-99% 3,4 units under temperature from 20 to À70 C. 14 Iminoimidazole-based Fe(II) complexes (F) 15 and iminopyridine (G) 16 were employed, which offered minor 3,4 enchained polyisoprene.…”