Fusing Carbocycles of Inequivalent Ring Size to a Bis(imino)pyridine-Iron Ethylene Polymerization Catalyst: Distinctive Effects on Activity, PE Molecular Weight, and Dispersity

Wang, Zheng; Solan, Gregory A.; Ma, Yanping; Liu, Qingbin; Liang, Tongling; Sun, Wen‐Hua

doi:10.34133/2019/9426063

Cited by 14 publications

(34 citation statements)

References 49 publications

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“…The microanalytical data for all five complexes were consistent with compositions based on the general formula LFeCl 2 . In addition, their IR spectra revealed ν(C=N) imine-stretching frequencies at around 1600 cm −1 , wavenumbers that are typical for that seen in similar N,N,N-iron complexes [3][4][5][6][7][8][19][20][21][22][23][24][31][32][33][34].…”

Section: Synthesis and Characterization Of Fe1-fe5mentioning

confidence: 88%

“…2-cyclooctyl-4,6-dibenzhydrylphenyl Fe3, 2,6-dicyclopentyl-4-benzhydrylphenyl Fe5) and will be described together. Each structure contains an iron center coordinated to two chloride atoms and three nitrogen donors from the chelating N,N,N-ligand to form a geometry best identified as a distorted square pyramidal [17,[19][20][21][22][23][24]. The square base of the pyramid is filled by the N1, N2, N3, and Cl2 while Cl1 occupies the apical position.…”

Section: Synthesis and Characterization Of Fe1-fe5mentioning

confidence: 99%

“…Hence, this work is concerned with using both of these co-catalysts with Fe2 chosen as the test precatalyst to permit an optimization of the reaction parameters. Changes to the run temperature, Al:Fe molar ratio, run time, and pressure will be independently undertaken for both Fe2/MMAO and Fe2/MAO before extending the corresponding set of optimized conditions to the remaining precatalysts, Fe1, Fe3, Fe4, and Fe5 [19][20][21][22][23][24]28,[31][32][33][34]. Typically, the polymerization runs will be performed in toluene at an ethylene pressure of 10 bar over a 30 min run time; the full set of data are collected in Tables 3 and 4.…”

Section: Ethylene Polymerizationmentioning

confidence: 99%

“…Of note, iron catalysts bearing carbocyclic-fused bis(imino)pyridine ligands have shown a capacity to display optimal productivity at temperatures in the range of 50-80 • C. In particular, bis(imino)pyridines bearing doubly or singly fused seven-membered rings have provided robust ligand frameworks for a range of iron(II) precatalysts (B-E, Scheme 1) [19][20][21][22][23][24]. In terms of catalytic performance, doubly fused B [19] bearing relatively small ortho-alkyl substituents displayed excellent activity (up to 10 7 g PE mol −1 (Fe) h −1 ) with the molecular weight of the resulting polyethylenes falling in the range of 3.5-96.9 kg mol −1 albeit with broad dispersity.…”

Section: Introductionmentioning

confidence: 99%

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Adjusting Ortho-Cycloalkyl Ring Size in a Cycloheptyl-Fused N,N,N-Iron Catalyst as Means to Control Catalytic Activity and Polyethylene Properties

et al. 2020

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Five examples of bis(arylimino)tetrahydrocyclohepta[b]pyridine dichloroiron(II) complex, [2-{(Ar)N=CMe}-9-{N(Ar)}C10H10N]FeCl2 (Ar = 2-(C5H9)-4,6-(CHPh2)2C6H2Fe1, 2-(C6H11)-4,6-(CHPh2)2C6H2Fe2, 2-(C8H15)-4,6-(CHPh2)2C6H2Fe3, 2-(C12H23)-4,6-(CHPh2)2C6H2Fe4, and 2,6-(C5H9)2-4-(CHPh2)C6H2Fe5), incorporating ortho-pairings based on either benzhydryl/cycloalkyl (ring sizes ranging from 5 to 12) or cyclopentyl/cyclopentyl groups, have been prepared in reasonable yield by employing a simple one-pot template strategy. Each complex was characterized by FT-IR spectroscopy, elemental analysis, and for Fe3 and Fe5 by single crystal X-ray diffraction; pseudo-square pyramidal geometries are a feature of their coordination spheres. On treatment of Fe1–Fe5 with modified methylaluminoxane (MMAO) or methylaluminoxane (MAO), a range in catalytic activities for ethylene polymerization were observed with benzhydryl/cyclopentyl-containing Fe1/MMAO achieving the maximum level of 15.3 × 106 g PE mol−1 (Fe) h−1 at an operating temperature of 70 °C. As a key trend, the activity was found to drop as the ortho-cycloalkyl ring size increased: Fe1C5H9/CHPh2~Fe5C5H9/C5H9 > Fe2C6H11/CHPh2 > Fe3C8H15/CHPh2 > Fe4C12H23/CHPh2. Furthermore, strictly linear polyethylenes (Tm > 126 °C) were formed with molecular weights again dependent on the ortho-cycloalkyl ring size (up to 55.6 kg mol−1 for Fe1/MAO); narrow dispersities were a characteristic of all the polymers (Mw/Mn range: 2.3–4.7), highlighting the well-controlled nature of these polymerizations.

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Section: Synthesis and Characterization Of Fe1-fe5mentioning

confidence: 88%

Section: Synthesis and Characterization Of Fe1-fe5mentioning

confidence: 99%

Section: Ethylene Polymerizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Adjusting Ortho-Cycloalkyl Ring Size in a Cycloheptyl-Fused N,N,N-Iron Catalyst as Means to Control Catalytic Activity and Polyethylene Properties

et al. 2020

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“…The polymer obtained with MAO as cocatalyst possessed high content of vinyl group (CH=CH2). [174,175] In general, the iron and cobalt catalysts can often form polymers with different kinds, e.g., linear α-olefins accompanied by waxes or oligomers from ethylene oligomerization or multimodal or broad molecular weight distributions for ethylene polymerization. For the catalytic mechanism of these precatalysts, it is generally accepted that bis(arylimino)pyridineiron and -cobalt catalysts propagate by a Cossee-Arlman mechanism, [176] in which sequential ethylene coordination and migratory insertion of the bound ethylene into a metal alkyl bond occur before some form of chain terminates occurs, thence the influence of the ligand structure is also significant which shows electronic and steric effects.…”

Section: General Chemistrymentioning

confidence: 99%

Paradox of Late Transition-Metal Catalysts in Ethylene Polymerization

Gansukh¹,

Zhang²,

Guo³

et al. 2020

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Polyolefin materials are the most synthesized polymer used nowadays and symbolize the development level of the national petrochemical industry, in which polyethylenes are major along with alternative product α-olefins for co-monomer and substrates for fine chemicals. Likely operating catalysts such as Ziegler-Natta and metallocene meet all demanding of various polyethylene materials, what is any business in developing late-transition metal catalysts for ethylene reactivity? In the past two decades, we realized the advantages of late-transition metal catalysts, such as easy variousness and easy preparation, good stability and high catalytic activity. Besides these, the characteristic different polyethylenes have been achieved as either highly linear polyethylene or highly branched polyethylenes. Therefore, there are some spaces in developing new catalytic system on the base of late-transition metal catalysts to compromise the demanding for new polyethylenes from sole ethylene polymerization.

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Research Progress of Iron Catalysts with N,N,N‐tridentate Ligands for Ethylene Polymerization

Hu,

Zhao,

Luo

et al. 2024

ChemistrySelect

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Some iron complexes are found to be effective catalysts of ethylene polymerization and have become a research hotspot due to their advantages of high activity, good thermal stability, and mild reaction conditions. Compared with other systems, iron catalysts bearing N,N,N‐tridentate ligand have good comprehensive performance in catalyzing ethylene polymerization. This review article focuses on changes in the framework of bis(imino)pyridyl ligand and the effect of different substituents on the catalytic performance of ethylene polymerization (activity, molecular weight, thermal stability, etc.) since 2019. Despite significant achievements, many opportunities and possibilities are yet to be fully addressed, and a brief outlook on the future of issues should be focused on is provided.

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Fusing Carbocycles of Inequivalent Ring Size to a Bis(imino)pyridine-Iron Ethylene Polymerization Catalyst: Distinctive Effects on Activity, PE Molecular Weight, and Dispersity

Abstract: The 4,6-bis(arylimino)-1,2,3,7,8,9,10-heptahydrocyclohepta[b]quinoline-iron(II) chlorides (aryl = 2,6-Me2C6H3Fe1; 2,6-Et2C6H3Fe2; 2,6-i-Pr2C6H3Fe3; 2,4,6-Me3C6 Show more

Cited by 14 publications

References 49 publications

Adjusting Ortho-Cycloalkyl Ring Size in a Cycloheptyl-Fused N,N,N-Iron Catalyst as Means to Control Catalytic Activity and Polyethylene Properties

Adjusting Ortho-Cycloalkyl Ring Size in a Cycloheptyl-Fused N,N,N-Iron Catalyst as Means to Control Catalytic Activity and Polyethylene Properties

Paradox of Late Transition-Metal Catalysts in Ethylene Polymerization

Research Progress of Iron Catalysts with N,N,N‐tridentate Ligands for Ethylene Polymerization

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