Polymerization of Ethylene Catalyzed by Iron Complex Bearing 2,6-Bis(imine)pyridyl Ligand: 1H and 2H NMR Monitoring of Ferrous Species Formed via Catalyst Activation with AlMe3, MAO, AlMe3/B(C6F5)3 and AlMe3/CPh3(C6F5)4

Talsi, Evgenii P.; Babushkin, Dmitrii E.; Semikolenova, Nina V.; Зудин, В. Н.; Panchenko, Valentina N.; Захаров, В. А.

doi:10.1002/1521-3935(20010601)202:10<2046::aid-macp2046>3.0.co;2-3

Cited by 89 publications

(51 citation statements)

References 5 publications

(10 reference statements)

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“…As an alternative explanation for the bimodal behavior, references [12,13,15] suggested the existence of two kinds of catalytic species whose ratios varied with changing Al/Fe ratio. When trialkylaluminum was used as activator in iron catalyst systems, two kinds of catalytic species were observed by 1 H NMR.…”

Section: Entrysupporting

confidence: 89%

“…A number of theoretical studies were reported based on this assumption [10,11]. Neutral Fe II complexes containing alkylaluminums in the coordination sphere of the metal have also been proposed [12,13]. EPR and Mössbauer studies revealed that the starting bis(imino)pyridine Fe II complex was oxidized to an Fe III species upon addition of MAO [14].…”

Section: Introductionmentioning

confidence: 95%

“…When trialkylaluminum was used as activator in iron catalyst systems, two kinds of catalytic species were observed by 1 H NMR. In fact, there were probably several kinds of catalytic species in the Fe(II)/MAO system [12]. So it was possible that there were two different kinds of catalytic species (a and b) in the catalytic system as shown in Scheme 1.…”

Section: Entrymentioning

confidence: 99%

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Studies on the activation and polymerization mechanism of ethylene polymerization catalyzed by bis(imino)pyridyl iron(II) precatalyst with alkylaluminum

Wang

Liu

Huang

et al. 2006

Journal of Molecular Catalysis A: Chemical

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Section: Entrysupporting

confidence: 89%

Section: Introductionmentioning

confidence: 95%

Section: Entrymentioning

confidence: 99%

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Studies on the activation and polymerization mechanism of ethylene polymerization catalyzed by bis(imino)pyridyl iron(II) precatalyst with alkylaluminum

Wang

Liu

Huang

et al. 2006

Journal of Molecular Catalysis A: Chemical

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“…The use of a cocatalyst, MAO, is essential to activate iron complexes for polymerization. As previously reported,17, 25, 28 it converts iron dichlorides into cationic species that are, at least in olefin polymerization, responsible for catalytic activity. Because of the strong Lewis acidity of MAO, it has been used as a scavenger for impurities in polymerization media.…”

Section: Discussionmentioning

confidence: 68%

“…GPC chromatograms consisted of relatively narrow‐to‐broad unimodal molecular mass distributions (MMDs) that ranged between 1.8 and 4.3 (Table 1, entries 17 and 19, respectively). Some chromatograms showed a shouldering of the peak toward low molecular weights 25. The ratio between r and m dyads was measured by 1 H NMR in deuterated benzene,26 according to the integration of the CH 2 and CH proton peaks of the polymer chain 27.…”

Section: Resultsmentioning

confidence: 99%

Iron‐based catalysts bearing bis(imido)–pyridine ligands for the polymerization of tert‐butyl acrylate

Castro

Lappalainen

Ahlgrén

et al. 2003

J. Polym. Sci. A Polym. Chem.

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Iron(II) dichloride complexes bearing a tridentate nitrogen donor ligand were investigated for the homopolymerization of tert-butyl acrylate after activation with methylaluminoxane. Two new complexes were synthesized, 2,6-bis[1-(cyclohexylimido)ethyl]pyridine iron chloride (FeCl 2 ) and 2,6-bis[1-(isopropylimido)ethyl]pyridine FeCl 2 , and the single-crystal X-ray structure of the latter one was determined. Turnover frequencies of the catalysts during polymerization ranged from 36 to 241 cycles/mol/h. The obtained polymers exhibited weight-average molecular weights ranging from 24,000 to 438,500 g/mol, and the molar mass distribution varied between 1.8 and 4.3. Activity of the catalytic system and the molar mass of the polymer are influenced by the ligand structure of the complexes as well as other polymerization conditions such as monomer concentration and temperature.

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Olefin Oligomerizations and Polymerizations Catalyzed by Iron and Cobalt Complexes Bearing Bis(imino)pyridine Ligands

Gibson

Solan

2010

Catalysis Without Precious Metals

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IntroductionThe capacity of 2,6 -bis(arylimino)pyridine -iron(II) and -cobalt(II) halide complexes, on activation with methylalumoxane ( MAO ), to act as exceptionally active catalysts (comparable with Group 4 metallocenes) for the conversion of ethylene to high density polyethylene ( HDPE ) was fi rst disclosed independently by Brookhart, Bennett and ourselves in 1998 ( Figure 5.1 ) [1 -7] . The signifi cance of this discovery was further highlighted by the complete absence at the time of examples of iron and cobalt complexes in olefi n polymerization applications. In comparison with early transition metal -based catalysts such as metallocenes, these late transition metal systems offer some distinct advantages which range from their relative ease of handling and manipulation, their reduced oxophilicity, to the cost -effectiveness and low toxicity of the metal centers employed. Moreover, by simple modifi cation of the 2,6 -bis(arylimino)pyridine ligand frame, exceedingly effi cient iron and cobalt oligomerization catalysts can also be generated, facilitating the formation of highly linear α -olefi ns with near ideal Schulz -Flory distributions. Since these initial fi ndings the past decade has witnessed a dramatic growth in reports associated with this class of late transition metal catalysts, and clear structure -activity relationships have emerged.This chapter is concerned with highlighting some of the more notable advances that have come to light as a result of identifying key factors that infl uence catalyst performance, particularly those related to precatalyst structure. The importance of the initiator and the role played in chain transfer is probed. Current mechanistic understanding is examined from both a spectroscopic and a computational viewpoint while efforts to prepare well -defi ned iron or cobalt alkyl catalysts are discussed. Efforts to heterogenize these homogeneous catalysts are briefl y reviewed, as is their use in multi -component catalysis.The reader is referred to a series of reviews for more general overviews of postmetallocene α -olefi n polymerization catalysts [8 -12] , while recent reviews relating to the versatility of 2,6 -bis(imino)pyridines and to iron -and cobalt -based catalysis itself have also been documented [13 -15] .

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Polymerization of Ethylene Catalyzed by Iron Complex Bearing 2,6-Bis(imine)pyridyl Ligand: 1H and 2H NMR Monitoring of Ferrous Species Formed via Catalyst Activation with AlMe3, MAO, AlMe3/B(C6F5)3 and AlMe3/CPh3(C6F5)4

Cited by 89 publications

References 5 publications

Studies on the activation and polymerization mechanism of ethylene polymerization catalyzed by bis(imino)pyridyl iron(II) precatalyst with alkylaluminum

Studies on the activation and polymerization mechanism of ethylene polymerization catalyzed by bis(imino)pyridyl iron(II) precatalyst with alkylaluminum

Iron‐based catalysts bearing bis(imido)–pyridine ligands for the polymerization of tert‐butyl acrylate

Olefin Oligomerizations and Polymerizations Catalyzed by Iron and Cobalt Complexes Bearing Bis(imino)pyridine Ligands

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