Aminosilylene-bridged ansa-zirconocenes for branched polyethylenes with bimodal molecular weight distributions

Han, Youngnam; Kim, Hyoseok; Lee, Min Hyung; Kim, Young-Jo; Lee, Ji Min; Lee, Yoon Sup; Do, Youngkyu

doi:10.1016/j.jorganchem.2009.09.003

Cited by 7 publications

(3 citation statements)

References 49 publications

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“…As a general observation, all the obtained polyethylene possessed narrow molecular weight distribution ( M w / M n ), consistent with a uniform active species in the polymerization process (Table ). The polymers produced by using 3a–3c /MAO showed similar melting points fell in the range from 129.6 to 134.8 °C (Table ), which are characteristic values of highly linear polyethylene . The comparative data on catalytic activity under the optimized conditions for each complex ( 3a , 3b and 3c ) in this manuscript and the two other previously reported complexes [mononuclear zirconium analogs of Zr[(C 4 H 3 O)CH=NNPh]Cl 3 (THF) 2 ( A) and Zr[(C 4 H 3 O)C (CH 3 ) = NNPh]Cl 3 (THF) 2 ( B) ] in the same laboratory were presented in Table S9.…”

Section: Resultssupporting

confidence: 59%

Alkyl substituents triggered an unexpected formation of mono‐and dinuclear zirconium hydrazonate complexes: synthesis, characterization and their catalytic behavior toward ethylene polymerization

Duan

Yuan

et al. 2020

Applied Organom Chemis

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Mononuclear zirconium complex 3a of the molecular identity [Zr[η2‐(C4H3O)C (Et) = NNPh]Cl3(THF)2], dinuclear zirconium complexes 3b [{Zr[η2‐(C4H3O)C(i‐Pr) = NNPh]2}2(μ2‐Cl)3(μ3‐Cl)2Li(Et2O)] and 3c [{Zr[η2‐(C4H3O)C(t‐Bu) = NNPh]2}2Cl2(μ2‐Cl)2] have been synthesized by the treatment of lithium salt of (C4H3O)C(R) = NNHPh (R = CH3CH2, 1a; R = (CH3)2CH, 1b; R = (CH3)3C, 1c), with different molar ratios of anhydrous zirconium tetrachloride. Of these, complex 3b was formed with lithium adduct and no such adduct was found in complex 3c. Compound 1a and all the zirconium complexes (3a‐3c) were structurally characterized by single‐crystal X‐ray diffraction studies. Thus, it revealed that each hydrazonato ligand acts in a strained η2‐coordination fashion for the three zirconium complexes. The molecular structures of the three zirconium complexes (3a‐3c) reveal the existence of intramolecular hydrogen bonding interactions. Interestingly, complexes 3a and 3b assemble into a two‐dimensional network structure through intermolecular hydrogen‐bonding interactions. Upon activation with methylaluminoxane (MAO), all the complexes namely 3a, 3b, and 3c exhibited moderate catalytic activities toward ethylene polymerization and produced high molecular weight polyethylene with narrow molecular weight distributions.

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Section: Resultssupporting

confidence: 59%

Alkyl substituents triggered an unexpected formation of mono‐and dinuclear zirconium hydrazonate complexes: synthesis, characterization and their catalytic behavior toward ethylene polymerization

Duan

Yuan

et al. 2020

Applied Organom Chemis

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“…All the melting points of the resultant polyethylene are within relatively narrow ranges and higher than 132 C, which indicates the formation of highdensity polyethylene (HDPE) obtained by 3 and 4, respectively. 30 The 1 H-NMR and 13 C-NMR spectrums for the PE sample listed in entry 7 of Table 6 analysis of the obtained PE conrms no presence of end vinyl groups (see ESI, Fig. 1 and 2 †), which implies that chain termination occurs with aluminum alkyls transfer for polyethylene.…”

Section: Catalytic Behavior For Ethylene Polymerizationmentioning

confidence: 95%

Group IV compounds bearing a novel tridentate N-donor ligand: synthesis, structures and ethylene polymerization

Yuan

et al. 2016

RSC Adv.

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“…5b-d,f,g,m,15 All the melting points of the resultant polyethylenes are within relatively narrow ranges and higher than 132 °C, which indicates the formation of high-density polyethylene (HDPE) obtained by 6 and 7, respectively. 16 In a similar procedure used for complexes 6 and 7/MAO systems, complexes 4 and 5/MAO systems were only roughly tested for ethylene polymerization under the same conditions (Al/M molar ratio of 1000, 10 atm, 50 °C and 30 min), respectively. Obvious ethylene consumption was not observed during the polymerization processes.…”

Section: Illustrated One Of Thementioning

confidence: 99%

Metal (Mg, Fe, Co, Zr and Ti) complexes derived from aminosilyl substituted aminopyridinato ligand: synthesis, structures and ethylene polymerization behaviors of the group 4 complexes

et al. 2012

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Lithium N-[(N,N-dimethylamino)dimethylsilyl]-2-pyridylamidate (2) was prepared from the reaction of new compound N-[(N,N-dimethylamino)dimethylsilyl]-2-pyridylamine (1) and LiBu(n). Treatment of the lithium salt (2) with an equal equivalent of MgBr(2)(THF)(2), FeCl(2) and CoCl(2) afforded the corresponding dinuclear complexes , , and , in which metal atoms possess similar trigonal bipyramidal geometries and each ligand functions as a bimetallic bridging binding aminopyridinato moiety with N-donation from the dimethylamino group. While the stoichiometric reaction of with ZrCl(4) gave the mononuclear zirconium complex (6); the seven coordinated zirconium atom adopts a distorted pentagonal bipyramid geometry and the ligand acts as monoanionic η(2)-aminopyridinato moiety with the pendant arm coordinated via N(CH(3))(2). The reaction of with one equivalent of TiCl(4)(THF)(2) produced the interesting dinuclear titanium complex (7) owing to the elimination of a (N,N-dimethylamino)dimethylsilyl group from the original ligand, and the two titanium centers present different coordination geometries. The molecular structures of the crystalline metal complexes have been confirmed by X-ray single crystal diffraction analysis. Upon activation with methylaluminoxane (MAO), both complexes and exhibited moderate catalytic activities toward ethylene polymerization and produced high molecular weight polyethylenes with broad molecular weight distributions.

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Aminosilylene-bridged ansa-zirconocenes for branched polyethylenes with bimodal molecular weight distributions

Cited by 7 publications

References 49 publications

Alkyl substituents triggered an unexpected formation of mono‐and dinuclear zirconium hydrazonate complexes: synthesis, characterization and their catalytic behavior toward ethylene polymerization

Alkyl substituents triggered an unexpected formation of mono‐and dinuclear zirconium hydrazonate complexes: synthesis, characterization and their catalytic behavior toward ethylene polymerization

Group IV compounds bearing a novel tridentate N-donor ligand: synthesis, structures and ethylene polymerization

Metal (Mg, Fe, Co, Zr and Ti) complexes derived from aminosilyl substituted aminopyridinato ligand: synthesis, structures and ethylene polymerization behaviors of the group 4 complexes

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