Completely Isospecific Polymerization of 1-Hexene Catalyzed by Hafnium(IV) Dichloro Complex Incorporating with an [OSSO]-type Bis(phenolate) Ligand

Nakata, Norio; Saito, Yûsuke; Watanabe, Takanori; Ishii, Akihiko

doi:10.1007/s11244-014-0252-1

Cited by 14 publications

(9 citation statements)

References 34 publications

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“…There are some reports on the polymerization of 1‐hexene using various types of catalysts . In this regard, for example, the microstructure of poly(1‐hexene) obtained using α‐diimine nickel catalysts was investigated by Sivaram and co‐workers, and a polymer structure with methyl, butyl and long‐chain branches was demonstrated.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, Nakata et al . reported the synthesis of poly(1‐hexene) with a narrow molecular weight distribution (MWD) and high stereospecific index (95%) using Hf‐based metallocene/methylaluminoxane catalytic system . Our group has reported recently on high‐molecular‐weight poly(1‐hexene) and its use in oil pipelines as a drag‐reducing agent .…”

Section: Introductionmentioning

confidence: 99%

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Mono‐ and binuclear nickel catalysts for 1‐hexene polymerization

Dechal

Khoshsefat

Ahmadjo

et al. 2018

Applied Organom Chemis

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Polymerization of 1-hexene was carried out using a mononuclear (MN) catalyst and two binuclear (BN 1 and BN 2 ) α-diimine Ni-based catalysts synthesized under controlled conditions. Ethylaluminium sesquichloride (EASC) was used as an efficient activator under various polymerization conditions. The highly active BN 2 catalyst (2372 g poly(1-hexene) (PH) mmol −1 cat) in comparison to BN 1 (920 g PH mmol −1 cat) and the MN catalyst (819 g PH mmol −1 cat) resulted in the highest viscosity-average molecular weight (M v ) of polymer. Moreover, the molecular weight distribution (MWD) of PH obtained using BN 2 /EASC was slightly broader than those obtained using BN 1 and MN (2.46 for BN 2 versus 2.30 and 1.96 for BN 1 and MN, respectively). These results, along with the highest extent of chain walking for BN 2 , were attributed to steric, nuclearity and electronic effects of the catalyst structures which could control the catalyst behaviour. Differential scanning calorimetry showed that the glass transition temperatures of polymers were in the range − 58 to −81°C, and broad melting peaks below and above 0°C were also observed.In addition, longer α-olefins (1-octene and 1-decene) were polymerized and characterized, for which higher yield, conversion and molecular weight were observed with a narrower MWD. The polymerization parameters such as polymerization time and polymerization temperature showed a significant influence on the productivity of the catalysts and M v of samples.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mono‐ and binuclear nickel catalysts for 1‐hexene polymerization

Dechal

Khoshsefat

Ahmadjo

et al. 2018

Applied Organom Chemis

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“…Yield: 0.048 g, 0.056 mmol, 94%. 1 129 A solution of t BuOH (35 μL, 0.37 mmol) in 5 mL of toluene was added to a preprepared solution of hafnium tetrabenzyl (50 mg, 0.06 mmol) in toluene (5 mL) at room temperature, and the reaction mixture was stirred overnight at room temperature. The solvent was removed under vacuum to afford the crude compound 5 (a mixture of 5A and 5B).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…Yield: 0.35 mg, 83%. 1 6). A solution of phenol (24.8 mg, 0.263 mmol) in toluene (5 mL) was added to a prepared solution of the respective complex 1 (40 mg, 0.052 mmol) in 5 mL of toluene at room temperature.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Benzimidazolin-2-iminato Hafnium Complexes: Synthesis, Characterization, and Catalytic Addition of Alcohols to Carbodiimides

et al. 2020

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A series of asymmetric imidazolin-2-iminato and benzimidazolin-2-iminato hafnium(IV) complexes were synthesized and fully characterized including single-crystal X-ray diffraction. The asymmetric imidazolin-2-iminato hafnium complex exhibits a shorter Hf–N bond length as compared with the corresponding benzimidazolin-2-iminato hafnium complex. These complexes were successfully utilized as catalysts for the addition of alcohols to carbodiimides. The synthesis of several active intermediates and kinetics, thermodynamics, and stoichiometric reaction studies allowed us to propose a mechanism for the reaction. The X-ray crystal structure of the monomeric Hf(O t Bu)4 is presented.

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“…Complexes of hafnium have been predominantly used as Lewis acid catalysts in various organic transformations, such as the polymerization of cyclic esters, and as catalysts for the homo‐ and copolymerization of α‐olefins . Recently, Hf‐MOF compounds have been used as active catalysts for the activation of small molecules .…”

Section: Introductionmentioning

confidence: 99%

Hydroboration of Aldehydes, Ketones, and Carbodiimides Promoted by Mono(imidazolin‐2‐iminato) Hafnium Complexes

et al. 2020

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Imidazolin‐2‐iminato hafnium complexes of the type [(ImRN)Hf(CH2Ph)3] were synthesized (ImtBuN = 1,3‐di‐tert‐butylimidazolin‐2‐iminato); ImDippN = 1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐iminato. The complexes were crystallized and structurally characterized. Despite the oxophilicity of the hafnium center, both hafnium complexes were catalytically active in the hydroboration of aldehydes, ketones, and carbodiimides. Herein, we present the influence of different substrates bearing electron‐withdrawing or electron‐donating groups on the catalytic reactions. Based on stoichiometric reaction in each process, plausible mechanistic scenarios are presented.

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Completely Isospecific Polymerization of 1-Hexene Catalyzed by Hafnium(IV) Dichloro Complex Incorporating with an [OSSO]-type Bis(phenolate) Ligand

Cited by 14 publications

References 34 publications

Mono‐ and binuclear nickel catalysts for 1‐hexene polymerization

Mono‐ and binuclear nickel catalysts for 1‐hexene polymerization

Benzimidazolin-2-iminato Hafnium Complexes: Synthesis, Characterization, and Catalytic Addition of Alcohols to Carbodiimides

Hydroboration of Aldehydes, Ketones, and Carbodiimides Promoted by Mono(imidazolin‐2‐iminato) Hafnium Complexes

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