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

Abstract

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 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. with minor 1,2 selectivity (<10%), and Co(II)Cl 2 L catalyst displays predominated cis-1,4 selectivity, which can be shifted to 1,2 selectivity by adding PPh 3 as an additive. Thus, tuning of the cis-1,4, trans-1,4 and 1,2 selectivity in full range via central metal and additive chosen by these 2,6-bis(dimethyl-2-oxazolin-2-yl)pyridine supported catalysts has been achieved. KAUST Repository

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. ,,,,− …”

“…273,275 Stereoblock polybutadienes have also been obtained with catalytic systems based on neodymium 269 and transition metals (Cr, Fe, Co). 266 Stereoblock polymers have also been prepared in the case of isoprene, using catalytic systems based on cobalt 270,271,274 and lanthanides (Y, Nd). 263,264,267,268,272 6.…”

“…Most recently, catalysts based on Cr­(III) complexes with tridentate nitrogen ligands, giving highly trans -1,4-polymers from butadiene, have been reported in the literature − (Figure ).…”

“…Polybutadienes with a low regioregularity ( cis -1,4/ trans -1,4/1,2 mixed structure) were obtained with catalysts based on iron­(II) and iron­(III) complexes with the 2,6-bis­(dimethyl-2-oxazolin-2-yl)­pyridine ligand (Figure ).…”

“…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 ).…”