Diethylbis(2,2′-bipyridine)iron/MAO. A Very Active and Stereospecific Catalyst for 1,3-Diene Polymerization

Polymerization of 1,3-butadiene catalyzed by a thermal robust, high selective and active iron catalyst: An applicable recipe for producing syndiotactic 1,2-polybutadiene

“…The activity has been improved by introducing bidentate and tridentate donor (ligand) [43e45], but the ability to the high selective polymerization is still limited, particularly at higher polymerization temperature, for example, high selectivity (1,2-selectivity: 91%) is achievable only at À78 C compromised by a low polymer yield (cal. 20%), which can be improved at 50 C along with scarifying selectivity [44]. Recent discoveries have suggested that there may be a surprising advantage to using commercial available phospha(i)te as third component for improving both selectivity and activity, and thus has offered a range of potential industrially relevant catalyst components, which are more forgiving in terms of easy synthetic feasibility, cost and labour intensity, yet still deliver excellent control over the stereoregularity of the polymer with satisfied catalytic activity.…”

Synthesis and characterization of syndiotactic 3,4-polyisoprene prepared with diethylbis(2,2′-bipyridine)iron–MAO

“…As we have reported in a previous paper [5], the polymer obtained at þ 25 8C is practically amorphous, while that obtained at 2 20 8C is partially crystalline. Information on the type of stereoregularity of the polymer has been obtained by X-ray investigation.…”

“…AlEt 3 -Ti(OR) 4 (R ¼ alkyl group) [1,2], (dmpe) 2 CrCl 2 -MAO (dmpe ¼ 1,2-bis(dimethyl-phosphino)ethane) [3] and some iron-based catalysts containing chelate nitrogen ligands [4,5]. The 3,4 content of these polymers is in general not very high, maximum ca.…”

“…Recently, using as catalyst (Bipy) 2 FeEt 2 -MAO (Bipy ¼ 2,2 0 -bipyridine), we have obtained [5] a crystalline 3,4-polyisoprene exhibiting an X-ray powder spectrum analogous to that reported in Ref. [4].…”

On the Crystal Structure of cis‐1,4‐Poly(2,3‐dimethyl‐1,3‐butadiene)

“…Recently, catalyst systems based on iron and alkylaluminium compounds have yielded samples of cis-PDMBD with high stereoregularity and crystallinity [15] from which it is possible to obtain X-ray diffraction data suitable for complete structural characterization of this polymer. In this Communication we report preliminary results on the crystal structure of cis-PDMBD obtained by the joint use of molecular mechanics and X-ray diffraction.…”