- Structure-stereospecificity relationships of propylene polymerization using substituted ansa-silylene(fluorenyl)(amido) titanium complexes
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ansa-Fluorenylamidotitanium complexes bearing various substituents on the nitrogen and fluorene (2a-d) were synthesized. The structures of the complexes were characterized by 1H and 13C NMR, and X-ray crystal analyses were performed for complexes 2a, 2b and 2d. The coordination mode of the fluorenyl group to the metal center was changed from η3 to η1 when a bulky group was introduced on the nitrogen or 2,3-position of the fluorenyl ring. Syndiotactic-specificity of the catalyst for the propylene polymerization was reduced when bulky group was introduced on the nitrogen. Least-square fitting analysis of the steric pentad distributions revealed that the stereodefect was mainly formed by the chain migration without monomer insertion, which is accelerated by the η1-coordination of the fluorenyl group.
- Tanaka, Ryo,Yanase, Chie,Cai, Zhengguo,Nakayama, Yuushou,Shiono, Takeshi
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- Copolymerization of ethylene with 1,1-disubstituted olefins catalyzed by ansa-(fluorenyl)(cyclododecylamido)dimethyltitanium complexes
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A series of titanium complexes with ansa-(fluorenyl)(cyclododecylamido) ligands, Me2Si(η3-R)(N-c-C12H 23)TiMe2 [R = fluorenyl (5), 2,7-tBu 2fluorenyl (6), 3,6-tBu2fluorenyl (7)], was synthesized. The crystal structure of complex 6 revealed η3- coordination of the fluorenyl moiety to the metal. Upon activation with trialkylaluminum-free modified methylaluminoxane, complexes 5-7 as well as the corresponding tBu amide complexes, Me2Si(η 3-R)(NtBu)TiMe2 [R = fluorenyl (2), 2,7- tBu2fluorenyl (3), 3,6-tBu2fluorenyl (4)], were adopted as the catalysts for the copolymerization of ethylene (E) and isobutylene (IB). Among these complexes, complex 6 was found to achieve the highest IB incorporation to produce alternating E-IB copolymers. Complex 6 system also achieved copolymerization of E and limonene. 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013. Copyright
- Nakayama, Yuushou,Sogo, Yuuichi,Cai, Zhengguo,Shiono, Takeshi
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- Silylene-bridged fluorenyl-containing ligands and zirconium complexes with C1 and Cs symmetry: general synthesis and olefin polymerization catalysis
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A variety of new silylene-bridged fluorenyl-containing ligands has been synthesized with good yields via a convenient synthetic route.Two dimethylsilylene-bridged (η5-indenyl)(η5-fluorenyl) (1) and (η5-cyclopentadienyl)(η5-fluorenyl) (2) zirconocene dichlorides with C1 and Cs molecular symmetry have also been prepared.Upon activation with methyl aluminoxane, the former produced a polypropylene of high molecular weight, but with low activity and isotacticity.The latter catalyzed non-stereospecific propylene polymerization without any zyndiotactic tendency, but with 40 and 20 times greater ethylene and propylene activity respectively than the former catalytic system.Keywords: Zirconium; Olefin; Polymerization catalysis; Fluorenyl ligands
- Chen, You-Xian,Rausch, Marvin D.,Chien, James C. W.
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- Stereospecific polymerization of propylene with group 4 ansa-fluorenylamidodimethyl complexes
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Group 4 [η1:η3-tert- butyl(dimethylfluorenylsilyl)amido]dimethyl complexes [t-BuNSiMe 2Flu]MMe2 (M = Ti, 1; Zr, 2; Hf, 3) were synthesized in a one-pot synthesis starting from the ligand, MeLi and MCl4 (M = Ti, Zr, Hf), respectively. The structures of these complexes were determined by X-ray crystallography and the results obtained revealed that the fluorenyl ligand coordinates to center metal in a η3-manner irrespective of center metal employed. Propylene polymerization was conducted at 0 or 20 °C in toluene by 1-3 combined with dried methylaluminoxane (MAO), which was prepared from the toluene solutions of MAO by removing free trialkylaluminiums, and HNMe2PhB(C6F5)4 in the presence of triisobutylaluminium. The 1-dried MAO system gave the polymer with syndiotactic triad (rr) of 63% at 0 °C, whereas 2 and 3 did not give any polymer in the same conditions. The 2-dried MAO system gave the polymer with the highest syndiotacticity (rr = 97%) at 20 °C, although the activity was low. The 3-dried MAO system did not give any polymer even at 20 °C. When HNMe2PhB(C6F5)4 was used in place of dried MAO at 20 °C, 1 gave almost atactic polymer, while 2 and 3 gave highly syndiotactic one (rr > 90%). These results indicate that the catalytic performance strongly depended on the center metal of the ansa- fluorenylamidodimethyl complexes as well as cocatalysts employed.
- Nishii, Kei,Hagihara, Hideaki,Ikeda, Tomiki,Akita, Munetaka,Shiono, Takeshi
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- The effect that 6-tert-butoxyhexyl functionalization has on ethylene polymerization in ansa-zirconocene dichlorides
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Ethylene polymerization studies have been carried out with novel precatalysts of the type: [(η5-C13 H8)-X(t-BuOC6H12)Me-(η5- C5H4)]ZrCl2 [X=C [1a], Si [2a]], [(η5-C13H8)-XMe2- (η5-(t-BuOC6H12C5 H3))] ZrCl2 [X=C [3a], Si [4a]] in the presence of excess methylalumoxane (MAO) to compare their catalytic activity and to delineate the effect of the 6-t-butoxyhexyl functionality on ethylene polymerization. The precatalysts [1a] and [2a] with the bridge functionality showed higher activity in ethylene polymerization than the corresponding complexes [3a] and [4a] which have it on the Cp ring moiety. On the other hand the silyl bridged complexes [2a] and [4a] produced a higher molecular weight polyethylene than the carbon-bridged one, regardless of the location of functional group.
- Lee, Hyosun,Lee, Choong Hoon
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- TRANSITION METAL COMPOUND AND CATALYST COMPOSITION INCLUDING SAME
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The present invention, implementing excellent catalytic activity in polyethylene polymerization, useful for producing polyethylene having a high intramolecular chain branch content without sacrificing physical properties such as molecular weight, melting point, density, new transition metal compounds, catalyst compositions comprising it, and a method for producing polyethylene using it.
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Paragraph 395-399
(2022/01/24)
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- In Situ Activation: Chances and Limitations to Form Ultrahigh Molecular Weight Syndiotactic Polypropylene with Metallocene Dichlorides
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Fluorenyl cyclopentadienyl Cs-symmetric ansa-metallocene (M = Zr, Hf) complexes I-IV featuring different bridging motifs (C and Si) were synthesized and subsequently examined in the syndiospecific coordinative polymerization of propylene. All complexes were activated in situ with triisobutylaluminum (TIBA) and [Ph3C][B(C6F5)4] (TrBCF) in order to highlight the benefits of this in situ activation, resulting in a significantly higher molecular weight and a significantly increased productivity in comparison to methylaluminoxane (MAO). The isopropylidene-bridged zirconocene Ia (ZrCl2[Me2C(η5-Flu)( η5-Cp)]) exhibited a high productivity (80000 kgPP (molcat h)-1) and stereoregularity ([rrrr] up to 93%) with a moderate molecular weight of polypropylene (PP), whereas the polymerization with the corresponding hafnocene Ib (HfCl2[Me2C(η5-Flu)( η5-Cp)]) resulted in a lower productivity and stereoregularity but yielded ultrahigh molecular weight polypropylene (Mw = 1100 kg mol-1). The backbone in II (HfCl2[Ph2C(η5-Flu)( η5-Cp)]) was associated with a higher productivity and molecular weight, while the syndiotacticity was not affected. In contrast, SC-XRD revealed a reduced dihedral angle and D value for Si-bridged hafnocenes III (HfCl2[Me2Si(η5-Flu)( η5-Cp)]) and IV (HfCl2[Ph2Si(η5-Flu)( η5-Cp)]), resulting in a more constrained geometry of the catalyst. This led to an increased molecular weight, while the productivity as well as the syndiotacticity decreased due to these structural parameters. Activation of Ib and II-IV with n-octyl-modified methylaluminoxane (MMAO) resulted in a lower molecular weight of the polymer, because the transfer of the growing polymer chain onto the Al center was enhanced. Nevertheless, the stereoregularity of MMAO-activated catalysts was slightly increased, probably due to a coordination of the ill-defined MMAO anion during the polymerization. DSC analysis exposed for syndiotactic polypropylene (sPP) produced by the highly active zirconocene Ia a defined melting transition (Tm up to 145.2 °C), whereas TIBA/TrBCF-activated hafnocenes Ib and II-IV gave polymers with no observable Tm value.
- Stieglitz, Lucas,Henschel, Daniel,Pehl, Thomas,Rieger, Bernhard
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p. 4055 - 4065
(2021/09/30)
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- Dinuclear metallocene compound, catalyst composition and method for preparing polyolefin using the same
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The present invention relates to: a dinuclear metallocene compound which has a new structure and can be used for polymerizing a high quality polyolefin with high molecular weight, a wide molecular weight distribution, and has high productivity. The dinuculeaer metallocne compound is represented by Chemical Formula 1 below. When the polyolefin is produced by using the catalyst composition including the dinuclear metallocene compound, the catalyst can exhibit high activity while having strong points of other homogeneous catalysts.
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Paragraph 0114
(2017/04/03)
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- New metallocene catalyst system
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Provided is a catalyst component for producing a polyolefin, which catalyst component comprises a metallocene catalyst having a structure according to a formulae (I):Cp1Cp2R"MQp wherein Cp1 and Cp2 are each independently a cyclopentadienyl derivative which may be substituted or unsubstituted, provided that at least one of the cyclopentadienyl derivatives comprises an N atom or a P atom in the cyclopentadienyl ring; R" is a structural bridge to impart stereorigidity between Cp1 and Cp2, and when only one of Cp1 and Cp2 comprises a P atom in the cyclopentadienyl ring, R" is attached to that phosphorous atom, or is attached to a carbon atom in the cyclopentadienyl ring distal to that phosphorous atom; M is a metal from Group IIIB, IVB, VB or VIB; Q is a hydrocarbyl group having from 1-20 carbon atoms, or a halogen; and p is the valence of M minus 2.
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- CH-Activierungsreaktionen an unverbrueckten und verbrueckten Zirconocenkomplexen zur Darstellung von Metallacyclen und deren Verwendung in der katalytischen Ethylenpolymerisation
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The reaction of phenylalkyl substituted zirconocenedichloride complexes with two equivalents of n-butyllithium gives metallacyclic zirconocene complexes. In this reaction aromatic CH bonds can be activated in unbridged and bridged metallocenedichloride co
- Licht, Andrea I.,Schneider, Katharina J.,Alt, Helmut G.
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p. 254 - 272
(2007/10/03)
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- Oxygen-containing, asymmetric "dual-side" zirconocenes: Investigations on a reversible chain transfer to aluminum
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A series of new oxygen-substituted, asymmetric zirconocene dichlorides (rac-{1-[5,6-(ethylenedioxy)-2-methyl-1-η5-indenyl]-2- (9-η5-fluorenyl)ethane}zirconium dichloride (3a), rac{1-[5,6-(ethylenedioxy)-2-methyl-1-η5-indenyl]-2- (9-η5-fluorenyl)ethane}dimethylzirconium (3b) and rac-{[5,6-ethylenedioxy)-2-methyl-1-η5-indenyl] (9-η5-fluorenyl) dimethylsilane} zirconium dichloride (3c)} have been prepared and their polymerization behavior was investigated in dependence of monomer concentration, temperature and catalyst activation. The presence of oxygen substituents on the indenyl ring results in a strong increase of polymerization activities and also of polymer molecular weights with decreasing Al/Zr ratio. Significantly higher molecular masses and activities were found for the dimethyl complex 3b after activation with [(C6H5)3C+] [(C6F5)4B-] deriving from the absence of chain transfer to aluminum and higher concentration of active cata lyst species. The mechanism of stereoerror formation of the oxygen-containing C1-symmetric catalyst was investigated by deuterium labeling studies on propene monomers. The results are discussed on the basis of a reversible chain transfer to aluminum.
- Kukral, Jürgen,Lehmus, Petri,Klinga, Martti,Leskel?, Markku,Rieger, Bernhard
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p. 1349 - 1356
(2007/10/03)
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- Synthese, Charakterisierung und Polymerisationseigenschaften verbrueckter Halbsandwichkomplexe des Titans, Zirconiums und Hafniums; Die Molekuelstruktur von [C13H8-SiMe2-NtBu]ZrCl2
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The synthesis of new ansa halfsandwich complexes of the type [Cp#-SiMe2-NtBu]MCl2 (Cp#=C13H8, C9H6, C5H4, C5H3tBu; M=Zr, Hf) as catalyst precursors for the polymerization of ethylene is described. The complexes were characterized by 1H-, 13C-, 29Si-, 15N- and 14N-NMR spectroscopy. From [C13H8-SiMe2-NtBu]ZrCl2 an X-ray structure was obtained. The activities of the catalysts and the properties of the polymers were investigated. The influence of the catalyst structure on the polymerization behaviour is discussed.
- Alt, Helmut G.,Foettinger, Klaus,Milius, Wolfgang
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Twenty-four (19 new) ansa-metallocene complexes of the type (C13H8-SiR2-C9H6-nR′n)ZrCl2 (n=0, 1; R=Me, Ph, alkenyl; R′=alkyl, alkenyl) have been synthezised, characterized and te
- Alt, Helmut G.,Jung, Michael
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p. 229 - 253
(2007/10/03)
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- The synthesis, characterization and polymerization behavior of ansa cyclopentadienyl fluorenyl complexes; the X-ray structures of the complexes [(C13H8)SiR2(C5H 4)]ZrCl2 (R = Me or Ph)
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The preparation and characterization of the ansa metallocene complexes [(C13H8)ER2(C5H 4)]ZrCl2, [(2,7-1Bu2C13H6)· SiR2(C5H4)]ZrCl2 and [(2,7-1Bu2C13H6)SiR 2(C13H8)]ZrCl2 (E = Si or Ge; R = Me or Ph) are reported. The crystal structures of [(C13H8)SiR2(C5H 4)]ZrCl2 (R = Me, or Ph) have been determined and are discussed. The complexes are compared in respect to their polymerisation behavior of propylene.
- Patsidis, Konstantinos,Alt, Helmut G.,Milius, Wolfgang,Palackal, Syriac J.
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