Iron complexes with ω-alkenyl substituted bis(arylimino)pyridine ligands as catalyst precursors for the oligomerization and polymerization of ethylene

Görl, Christian; Alt, Helmut G.

doi:10.1016/j.molcata.2007.04.001

Cited by 32 publications

(21 citation statements)

References 21 publications

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“…3,3‐Diethyl‐1‐(2‐vinylphenyl)triaz‐1‐ene ( 1 ; Scheme ) was synthesized in 83 % yield according to the literature57 by the reaction of 2‐vinylaniline58 with HCl and aqueous NaNO 2 at –5 °C followed by quenching with Et 2 NH and K 2 CO 3 . Treatment of 1 with the 2 nd ‐generation Grubbs catalyst RuCl 2 (PCy 3 )(IMesH 2 )(CHPh) (Cy = cyclohexyl) in the presence of CuCl yielded the green complex 2 in 60 % yield.…”

Section: Resultsmentioning

confidence: 99%

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Ruthenium–Triazene Complexes as Latent Catalysts for UV‐Induced ROMP

et al. 2013

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Three novel ruthenium(II) complexes, RuX2(IMesH2)[N,N‐diethyl‐N′‐(2‐benzylidene)triazene] [IMesH2 = 1,3‐dimesitylimidazolin‐2‐ylidene; X = Cl– (2), CF3COO– (3), C6F5COO– (4)] are described. Single‐crystal X‐ray structure analysis of compounds 2–4 revealed that the triazene ligand exists in the trans form and that the aryl‐connected nitrogen atom of the triazene binds to the ruthenium atom to form a five‐membered chelate ring. Compounds 2–4 were applied to the UV‐induced ring‐opening metathesis polymerization (ROMP) of cis‐cyclooctene (5) and dicyclopentadiene (6). Whereas all three precatalysts show pronounced thermal latency in the presence of 5 or 6, only compound 2 displays significant photo‐ROMP activity. The photoreactivity of precatalysts 2–4, which decreases with increasing electron‐withdrawing character and with decreasing pKa of the X groups, is discussed and correlated with the X‐ray data of 2–4, with low‐temperature 1H NMR measurements as well as with cyclovoltammetric measurements.

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Section: Resultsmentioning

confidence: 99%

“…Tetrabutylammonium hexafluorophosphate and tetrabutylammonium trifluoromethanesulfonate were used as electrolytes. 2‐Vinylaniline was synthesized according to the literature 58. CCDC‐913241 ( 2 ), ‐CCDC‐918365 ( 3 ), and ‐CCDC‐913242 ( 4 ) contain the supplementary crystallographic data for this paper.…”

Section: Methodsmentioning

confidence: 99%

Ruthenium–Triazene Complexes as Latent Catalysts for UV‐Induced ROMP

et al. 2013

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“…52 Usually, iron(III) complexes with alkyl substituted iminophenyl rings exhibit higher polymerization activities than do their iron(II) analogues, however the α-alkenyl substituted iron(III) complexes exhibited similar 80 activities to their iron(II) analogues. 51 Longer α-alkenyl chains on these bis(arylimino)pyridine had a positive effect on the observed polymerization activities, whereas longer alkyl chains on the bis(arylimino)pyridine led to decreased activity. The Alt group also studied the influence of the para aryl substituent (Scheme 11) on the oligomerization and polymerization of ethylene.…”

Section: Bis(imino)pyridine Type Ligationmentioning

confidence: 95%

“…6,7,18,19,49,50 The Alt group investigated a family of bis(arylimino)pyridine iron(II) complexes bearing ω-alkenyl substituents (Scheme 10) for ethylene oligomerization and 70 polymerization. 51 Complexes bearing substituents both at the 2-and 6-positions of the iminophenyl rings only produced polyethylene, whereas if only one ortho imino group was present, the complexes produced, depending on bulk of the substituent, either oligomer/polymer mixtures or only 75 oligomeric mixtures; the reaction conditions could also affect the products formed. 52 Usually, iron(III) complexes with alkyl substituted iminophenyl rings exhibit higher polymerization activities than do their iron(II) analogues, however the α-alkenyl substituted iron(III) complexes exhibited similar 80 activities to their iron(II) analogues.…”

Section: Bis(imino)pyridine Type Ligationmentioning

confidence: 99%

Bi- and tri-dentate imino-based iron and cobalt pre-catalysts for ethylene oligo-/polymerization

Feng

Wang

et al. 2014

Inorg. Chem. Front.

118

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Recent progress on the use of iron and cobalt complex precatalysts for ethylene reactivity is reviewed. The review is organized in terms of the denticity of the chelate ligands 10 employed, with particular reference to the influence of the ligand frameworks and their substituents on the catalytic performance for ethylene oligomerization/polymerization catalysis. The majority of the systems bear tri-dentate ligation at the iron/cobalt centre, though it is clear that bi-dentate 15 iron/cobalt complex pre-catalysts have also attracted significant attention. Such systems produce in most cases highly linear products ranging from oligomeric α-olefins to high molecular weight polyethylene, and as such are promising candidates for both academic and industrial 20 considerations.

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“…[9] Alt recently described the synthesis and catalytic activity of a wide range of FeCl 2 (pdi) complexes similar to those previously reported by the Herrmann and Jin groups, but, somewhat paradoxically, no conclusive evidence of catalyst self-immobilization was found. [18] In order to obtain some additional evidence of the existence of unusual effects on the catalytic behavior of the 4-allyl-functionalized complexes 6 and 9, we decided to examine the morphology of the polymers generated with these catalysts by using scanning electron microscopy (SEM). Self-immobilization of catalysts is thought to lead the formation of microscopic polymer particles, which mimic the initial immobilized catalyst seeds.…”

Section: Entrymentioning

confidence: 99%