High-Temperature Catalysts for the Production of α-Olefins Based on Iron(II) and Iron(III) Tridentate Bis(imino)pyridine Complexes with Double Pattern of Substitution:  ortho-Methyl plus meta-Aryl

Ionkin, Alex S.; Marshall, William J.; Adelman, Douglas J.; Fones, Barbara Bobik; Fish, Brian M.; Schiffhauer, Matthew F.

doi:10.1021/om051069o

Cited by 59 publications

(39 citation statements)

References 30 publications

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“…Generally for a given aniline, the condensation reaction occurs more readily for 2,6-pyridinedicarboxaldehyde than for 2,6-diacetylpyridine, while 2,6-dibenzoylpyridine is much less reactive under these conditions. Using this simple approach a wide variety of symmetrical examples of 1 have been prepared in which the steric bulk and electronic properties of the aryl groups have been systematically varied (see Tables 1 and 2 for complexed examples [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,17,20,21,24,26,27,29,28,32,33,36,37,38,39,40,41,42,44,48,18,16,19,22,23,25,30,31,34,35,45,43,46,…”

Section: Ligand Preparationmentioning

confidence: 99%

“…X-ray structures of 1 (R = H or Me) reveal that, in the solid state, the imino nitrogen atoms prefer to be configured trans with respect to the central pyridine nitrogen [36,44,31,74,75,76,77,78] (Yap and Gambarotta, CSD private communication) with the N -aryl groups essentially orthogonal to the pyridyl-imine planes ( Fig. 3 ).…”

Section: Ligand Preparationmentioning

confidence: 99%

“…Notably, the cobalt-based catalyst bearing an ortho -CF 3 group in combination with an ortho -F substituent ( j ) displays an activity greater than 100,000 g (mmol h bar) -1 , which is comparable in performance to the most active iron catalysts. A number of substitution patterns involving ortho -methyl groups and meta -fluorinated aryls (F or CF 3 groups) have been investigated by Ionkin et al [31] . Ligands involving a 2,3-pattern of ortho -methyl and meta -aryl ( k ) or with two meta -aryls on one side and two ortho -methyls ( l and l 1 ) on the other yield highly active iron oligomerisation Incorporating ortho -benzyl groups ( m ) has been reported to give a very high activity iron catalyst (40,800 g (mmol h bar) -1 cf.…”

Section: Catalytic Evaluationmentioning

confidence: 99%

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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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Section: Ligand Preparationmentioning

confidence: 99%

Section: Ligand Preparationmentioning

confidence: 99%

Section: Catalytic Evaluationmentioning

confidence: 99%

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Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Gibson¹,

Solan²

2008

Topics in Organometallic Chemistry

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“…[41][42][43] In the case of aromatic N-substituents, the presence of ortho-substituents is required to prevent the formation of homoleptic ion pairs. 44 Thus, more than 70 solid state structures are reported Complexes with N-aryl substituents. In light of the apparent requirement for bulky N-substituents to stabilize (LNNN)FeX2, we set out to investigate the accessibility of the analogous heteroleptic complexes (LNNN)Fe(OR)2 from authentic halide precursors.…”

Section: Fe1mentioning

confidence: 99%

Lactide polymerization with iron alkoxide complexes

et al. 2015

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RésuméLes essais préliminaires pour préparer des alcoolates de fer à partir du bichlorure ou bibromure de fer (II), en les combinant avec des ligands de type diimino pyridine, ont engendré la formation de complexes homoleptiques et hétéroleptiques, dépendant des substituants sur les branches imines du ligand. Ces complexes homoleptiques octaédriques et paramagnétiques ont été étudiés par rapport à leurs propriétés spectroscopiques et cristallographiques. De plus, la synthèse des complexes de fer hétéroleptique a engendré de bons précurseurs penta-coordonnés pour les réactions de substitution de ligands avec des alcoolates de métaux alcalins, de manière à produire les dialcoolates de fer (II) désirés. Des techniques d'analyse telles que la spectroscopie UV-vis, l'analyse élémentaire, la spectrométrie de masse à haute résolution et la cristallographie aux rayons X ont été utilisées pour caractériser ces complexes de fer.L'activité catalytique de ces complexes de fer (II) a aussi été étudiée par rapport à la polymérisation du lactide; les dialcoolates convoités ont été générés in-situ en raison de la difficulté à produire et à isoler les dérivés alcoolates des complexes diimino pyridine de fer. Une étude approfondie a aussi été faite sur les réactions de polymérisation, surtout par rapport aux valeurs de conversion à l'échelle du temps, ainsi qu'à la tacticité des chaines de polymères obtenues. Ces analyses ont été effectuées par l'entremise de la spectroscopie de résonance magnétique nucléaire, de la chromatographie d'exclusion stérique, et de la spectrométrie de masse MALDI (désorption-ionisation laser assistée par matrice).Mots-clés: catalyseur de fer, polymérisation de lactide, ligands diiminopyridine, polymères biodégradables, chimie verte.iii AbstractInitial attempts to prepare iron alkoxide complexes, from iron (II) dichloride or dibromide, in combination with various bis(imino) pyridine ligands, led to the formation of homoleptic and heteroleptic complexes depending on the N-substituents on the imino moieties. A study was made of the resulting paramagnetic octahedral homoleptic complexes, with respect to their spectroscopic properties, as well as their crystallographic parameters. Alternatively, the synthesis of penta-coordinate heteroleptic iron (II) complexes provided good precursors for the ligand substitution reactions with alkaline alkoxides, to produce the desired iron bis (alkoxide) derivatives. Methods such as UV-vis spectroscopy, elemental analysis, high resolution mass spectrometry and X-ray crystallography were used for the characterization of these iron complexes.The catalytic activity of these iron (II) complexes was investigated with respect to lactide polymerization; the desired bis(alkoxide) species were generated in-situ due to the difficulties in isolating pure alkoxide derivatives of the bis(imino) pyridine iron (II) complexes. An informative study was made of both time-scale conversion values, as well as tacticity properties of the resulting polylactic acid chains, through proton nuclear...

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“…Evaluation of difl uoro -substituted ligands ( v , one F always ortho) has also been performed (with MMAO) for both iron and cobalt, and high oligomerization activities were found for the iron systems ( 1v ), whereas the cobalt systems ( 2v ) were inactive [36,37] . The fl uoro or fl uorocarbyl substituent need not be bound directly to the N -aryl group, with a number of highly active iron oligomerization systems based on more remote substitutions; see for example the 2,3 -pattern of ortho -methyl and meta -aryl(CF 3 ) in 1w or 3,5 -pattern of metaaryl(CF 3 )s in 1x [42] .…”

Section: Substituent Effectsmentioning

confidence: 99%

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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High-Temperature Catalysts for the Production of α-Olefins Based on Iron(II) and Iron(III) Tridentate Bis(imino)pyridine Complexes with Double Pattern of Substitution: ortho-Methyl plus meta-Aryl

Cited by 59 publications

References 30 publications

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Lactide polymerization with iron alkoxide complexes

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

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