Probing the Effect of Binding Site and Metal Centre Variation in Pentadentate Oligopyridylimine‐Bearing Bimetallic (Fe2, Co2, Ni2) Ethylene Oligomerisation Catalysts

Armitage, Andrew P.; Champouret, Yohan; Grigoli, Hubert; Pelletier, Jérémie D. A.; Singh, Kuldip; Solan, Gregory A.

doi:10.1002/ejic.200800650

Cited by 45 publications

(13 citation statements)

References 49 publications

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“…All 9 examples found showed meridional ligand geometry. [27][28][29][30][31][32] It is known that five-coordination can be square-pyramidal or trigonal-bipyramidal, but for many complexes the geometry adopted lies between these two extreme structures. In this case, the structural index parameter τ 33 was used in order to determine the position on the structural spectrum.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of β-triketimine cobalt complexes and their behaviour in the polymerization of 1,3-butadiene

Alnajrani

Mair

2014

Dalton Trans.

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Three β-triketimine ligands, (L(1): [CH{CMeN(2,4,6-Me3-C6H2)}2C(CMe3N(2-MeO-C6H4)], L(2): [CH{CMeN(2,4-Me2-C6H3)}2C(CMe3N(2-MeO-C6H4)] and L(3): [CH{CMeN(2-Me-C6H4)}2C(CMe3N(2-MeO-C6H4)]), were synthesized and then characterized by (1)H and (13)C{(1)H} NMR spectroscopy, elemental analysis and electrospray (ES) MS. β-triketimine cobalt(ii) complexes were then prepared by the interaction of cobalt(ii) bromide with L(1-3) in the presence of NaBArF (BArF = [{3,5-(CF3)2-C6H3}4B](-) ). Five-coordinate dimeric bromide-bridged species [(LCoμ-Br)2][BArF]2 were obtained. The geometry of the complexes was found by single-crystal X-ray diffraction to be slightly distorted square-pyramidal. The polymerization of 1,3-butadiene catalysed by these complexes upon activation with methylaluminoxane (MAO) in chlorobenzene yielded high cis-1,4-polybutadiene (>97% cis). The effect of steric and electronic properties of the ligands on the performance of the catalytic system was investigated: it was found that ligands with fewer methyl substituents gave more active catalytic systems. It was also found that increasing MAO: Co ratio resulted in higher activity. Stereoselectivity of all catalysts slightly decreased at higher temperature, whereas activities were maximised at 20 °C, where very high values of activity were recorded.

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Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of β-triketimine cobalt complexes and their behaviour in the polymerization of 1,3-butadiene

Alnajrani

Mair

2014

Dalton Trans.

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“…While the 2,6-bis(imino)pyridine ligand frame has continued to lead the way, the past 10 years has also seen the development of alternative ligand sets that can act as compatible supports for iron and cobalt ethylene oligomerisation/polymerisation catalysts ( Table 4 ) [46,50,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209] ; active catalysts based on bimetallic iron and cobalt precatalysts have also started to emerge ( Table 5 ) [54,210,211,212,213,214,215] . In the main, these systems show lower activities than the prototype bis(imino)pyridine-based catalysts, although several of these systems have significantly started to approach their catalytic performances (e.g.…”

Section: Alternative Iron and Cobalt Catalystsmentioning

confidence: 99%

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Gibson¹,

Solan²

2008

Topics in Organometallic Chemistry

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This chapter describes the brief history of iron or cobalt catalysts for olefin polymerisation and oligomerisation. Since the discovery in 1998 that 2,6-bis(imino)pyridine iron and cobalt halides, on activation with MAO, can convert ethylene to highly linear polyethylene, numerous reports have been concerned with ligand modification, mechanisms for precatalyst activation, identifying the active species and understanding the mode of propagation/chain transfer. In addition, heterogenisation of this class of catalysts, their incorporation into macrocycles/ polymers and their use in reactor blending/tandem catalysis has seen some important developments; alternative ligand architectures that can support active iron and cobalt catalysts are also discussed as are different types of olefinic monomer.

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“…Recently, cationic diimino-nickel complexes have been found to be active as procatalysts in ethylene polymerization and oligomerization [7]. Extensive investigations for new procatalysts of various late-transition metal complexes have been conducted [8], and nickel complexes bearing bidentate [9][10][11][12][13][14][15][16][17][18][19] or tridentate ligands [20][21][22][23][24] have been the focus of much research. Beyond our efforts for iron procatalysts in ethylene reactivity [25,26], some nickel procatalysts were also investigated and possessed good activities [27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization and ethylene oligomerization behavior of 2-(chloro-substituted-1H-benzoimidazol-2-yl)-6-(1-aryliminoethyl)pyridylnickel dihalides

Chen

Zhang

et al. 2011

Inorganica Chimica Acta

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Probing the Effect of Binding Site and Metal Centre Variation in Pentadentate Oligopyridylimine‐Bearing Bimetallic (Fe₂, Co₂, Ni₂) Ethylene Oligomerisation Catalysts

Cited by 45 publications

References 49 publications

Synthesis and characterization of β-triketimine cobalt complexes and their behaviour in the polymerization of 1,3-butadiene

Synthesis and characterization of β-triketimine cobalt complexes and their behaviour in the polymerization of 1,3-butadiene

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Synthesis, characterization and ethylene oligomerization behavior of 2-(chloro-substituted-1H-benzoimidazol-2-yl)-6-(1-aryliminoethyl)pyridylnickel dihalides

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