Highly trans‐1,4‐specific polymerization of 1,3‐butadiene catalyzed by [2,6‐bis{(4S)‐ (−)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine] chromium complex activated with modified methylaluminoxane

Abstract

Chromium complexes with N,N,N‐tridentate ligands, LCrCl3 (L = 2,6‐bis{(4S)‐(−)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine (1), 2,2′:6′,2″‐terpyridine (2), and 4,4′,4″‐tri‐tert‐butyl‐2,2′:6′,2″‐terpyridine (3)), were prepared. The structures of 1 and 2 were determined by X‐ray crystallography. Upon activation with modified methylaluminoxane (MMAO), 1 catalyzed the polymerization of 1,3‐butadiene, while 2 and 3 was inactive. The obtained poly(1,3‐butadiene) obtained with 1‐MMAO was found to have completely trans‐1,4 structure. The 1‐MMAO system also showed catalytic activity for the polymerization of isoprene to give polyisoprene with trans‐1,4 (68%) and cis‐1,4 (32%) structure. Copyright © 2011 Society of Chemical Industry

Determination of configurational isomers in polybutadienes by 1H and 13C NMR spectroscopy

“…Unfortunately, this approach is inapplicable in the case of PB: No natural analogs of this polymer have been discovered on Earth. There are several com munications about the synthesis of PB with a very high content (above 99 mol %) of trans 1,4 or cis 1,4 units [102,103], but their experimental and methodological verification are insufficiently convincing.…”

Pyridine–oxazoline and quinoline–oxazoline ligated cobalt complexes: Synthesis, characterization, and 1,3-butadiene polymerization behaviors

“…Iron(II) [34] and ruthenium(II) [35] complexes bearing 2,6-bis[4'-(S)-isopropyloxazolin-2'-yl]pyridine were reported as catalytic precursors for ethylene polymerization but exhibited low activities. To our knowledge, there is only one paper that reported the polymerization of 1,3-butadiene with 2,6-bis[4'-(S)-isopropyloxazolin-2'-yl]pyridine chromium trichloride/MMAO catalyst [36]. On the other hand, many studies have disclosed that the ligand environment of the complex affected catalytic behaviors significantly.…”

Trans-stereospecific polymerization of butadiene and random copolymerization with styrene using borohydrido neodymium/magnesium dialkyl catalysts

“…The trans-polymerization of butadiene has been in turn less explored since the pioneer disclosures of Natta [11][12][13]. It mainly involves catalysts based on metals of the group IV [14,15], group V [16][17][18], chromium [19,20], iron [21,22], and also late transition metals like rhodium [23] or cobalt [24]. The resulting polymers display good hardness and abrasion resistance [25][26][27][28], which motivated the search for the development of new trans-selective catalytic systems.…”