- π-Indenyl substituted zirconium compounds containing terminal bonded phosphanylphosphido ligands [Ind2Zr(Cl){(Me3Si)P-PR 2-κP1}]. Synthesis, X-ray analysis and NMR studies
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Dichloro-bis(indenyl)zirconium(IV) reacts with lithium derivatives of diphosphanes R2P-P(SiMe3)Li (R = tBu, Et 2N, iPr2N) to form complexes with terminal phosphanylphosphido ligands - [Ind2Zr(Cl)-{(PSiMe3)P- PR2-κP1}]. These compounds are extremely sensitive towards moisture and oxygen. The solid state structures of these complexes were established by single crystal X-ray diffraction. The nitrogen bearing groups R (Et2N or iPr2N) significantly lengthen the P-P distances in the related complexes and change the geometry around the phosphido phosphorus in such a way that it becomes less planar.
- Lapczuk-Krygier, Agnieszka,Baranowska, Katarzyna,Ponikiewski, Lukasz,Matern, Eberhard,Pikies, Jerzy
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- Electronic effects in homogeneous indenylzirconium Ziegler-Natta catalysts
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A series of new bis(indenyl)zirconium(IV) complexes of the general formula (η5-4,7-X2C9H5) 2ZrCl2 and (η5-4,7-X2C9H5) 2Zr(CH2C6H5)2 (where X = H, CH3, OCH3, and F) were synthesized in order to investigate the electronic effects of substituents on the nature of the catalytic species in homogeneous Ziegler-Natta catalysts. By use of poly(methylaluminoxane) as cocatalyst, the activity of these complexes as catalyst precursors in the polymerization of ethylene was examined. The substitution with electron-withdrawing groups resulted in a decrease of both molecular weights and productivity, whereas in the case of electron donors, like methyl groups, no significant change in productivity and average molecular weight was observed. These effects support the hypothesis of a polar or ionic character of the catalytic species. The molecular structure of (η5-4,7-F2C9H5) 2Zr(CH2C6H5)2 was determined by X-ray diffraction. The complex crystallizes in space group P21/c (No. 14) with cell parameters a = 10.786 (1) A?, b = 11.084 (2) A?, c = 21.602 (2) A?, β = 98.30 (1)?, Z = 4, R = 0.0220, and Rw = 0.0295.
- Piccolrovazzi, Nicoletta,Pino, Piero,Consiglio, Giambattista,Sironi, Angelo,Moret, Massimo
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- Metal organic transition metal compound, catalyst-based, polyolefin
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The present invention relates to non-symmetrical organometallic transition metal compounds of the compound of the formula (I) where R8 and R9 are identical or different and each an substituted or unsubstituted organic radical having from 1 to 40 carbon atoms, catalyst systems comprising at least one of the organometallic transition metal compounds of the present invention and a process for preparing polyolefins by polymerization or copolymerization of at least one olefin in the presence of one of the catalyst systems of the present invention.
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Paragraph 0046; 0054-0055
(2016/12/26)
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- Selective halodemethylation reactions of metallocene dimethyls with triphenylmethyl chloride and benzyl bromide
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NMR-scale reactions of several group 4 metallocene dimethyls with either trityl chloride or benzyl bromide gave the corresponding L2M(Me)X complexes selectively. Five reactions, including syntheses of Cp2-Zr(Me)Cl and Ind2Zr(Me)Cl, were conducted on a preparative scale to afford useful isolated yields of L2M-(Me)Cl complexes.
- Hawrelak, Eric J.,Deck, Paul A.
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- A counterintuitive, yet efficient synthesis of bis(indenyl)zirconium dihalides
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The use of bisindenyl zirconium dimethyl in the synthesis of the corresponding dihalides is described. The synthesis of Ind2 ZrCl2 has been carried out, cleanly and quantitatively, by chlorination of Ind2ZrMe2 (2) with a variety of inorganic chlorides, including BCl3, SCl2 in either toluene or methylene chloride, and HCl in Et2O. The latter method is the preferred one, since it produces methane as the only byproduct, and the formed Ind2ZrCl2 precipitates quantitatively from the Et2O solvent: a simple filtration then gives the analytically pure product in quantitative yield. Ind2ZrBr2 and Ind2ZrI2 are obtained by reacting 2 with Br2 and I2, respectively. The 'inverse' synthesis of metallocene dichlorides by chlorination of their dimethyl 'derivatives' has advantages compared to the classic method: first, Ind2ZrCl2 is obtained in higher yield (90-96%); second, it is easier to purify (at the dimethyl stage) and is obtained free from LiCl. Five bisindenyl zirconium complexes with different sigma ligands have been investigated in solution propylene polymerizations: it is found that the σ-ligands have no relevant influence on the catalyst activity, nor on the polymer properties.
- Balboni, Davide,Camurati, Isabella,Ingurgio, Antonio Cascio,Guidotti, Simona,Focante, Francesca,Resconi, Luigi
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- Methyl-versus-chloride exchange as a measure of electron density at the metal center of ring-substituted zirconocene complexes
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Methyl-versus-cloride exchange equilibria between different zirconocene complexes provide a sensitive measure of relative electron densities at the Zr centers of these complexes. As expected, methyl and trimethyl silyl substituents increase the electron density at the Zr center of a bis(cyclopentadienyl) Zr(IV) complex; the same holds for a dimethyl silyl bridge. In bis(indenyl) complexes, on the other hand, electron density at the metal center is reduced and substituent and bridge effects are different from those observed in bis(cyclopentadienyl) Zr(IV) complexes.
- Weiser, Ulrich,Babushkin, Dimitrii,Brintzinger, Hans-Herbert
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p. 920 - 923
(2008/10/08)
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- Syntheses of polymethylene bridged dinuclear zirconocenes and investigation of their polymerisation activities
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The polymethylene bridged dinuclear zirconocenes [(CH2)n (C5H4)2][(C9H7)ZrCl 2]2 (n=3 (10), 5 (11), 7 (12), 9 (13)) have been synthesised by treating not on
- Noh, Seok Kyun,Kim, Jongmun,Jung, Jaehoon,Ra, Choon Sup,Lee, Dong-Ho,Lee, Hun Bong,Lee, Sang Won,Huh, Wan Soo
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- Electronic effects in Ziegler-Natta polymerization of propylene and ethylene using soluble metallocene catalysts
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The polymerization of ethylene was studied by using a series of (η5-5,6-X2C9H5) 2ZrCl2 catalysts (4a, X = H; 4b, X = CH3; 4d, X = OCH3; 4e, X = Cl), and the polymerization of propylene and ethylene was studied by using a number of the corresponding racemic, ethylene-bridged analogues (5a, X = H; 5b, X = CH3; 5d, X = OCH3). The presence of electron-withdrawing substituents on the indenyl ring in catalysts 4a-e led to a decrease in catalytic activity for ethylene polymerization and a decrease in polymer molecular weights. Ethylene-bridged catalysts produced lower molecular weight polyethylene than their unbridged counterparts but possessed similar activities toward ethylene. Similar trends in catalytic activity toward propylene were observed by using the ethylene-bridged catalysts, but the molecular weight of polypropylene was not as sensitive to changes in electron density at the metal center. Surprisingly, the stereoselectivity of propylene insertion was sensitive to electronic effects; an increase in electron density at the metal center led to a decrease in the stereoselectivity of propylene insertion.
- Lee, Ik-Mo,Gauthier, William J.,Ball, JoAnne M.,Iyengar, Bhagavathi,Collins, Scott
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p. 2115 - 2122
(2008/10/08)
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- THE FORMATION, CRYSTAL AND MOLECULAR STRUCTURES OF BIS(η5-INDENYL)DICARBONYLTITANIUM AND BIS(η5-INDENYL)DICARBONYLZIRCONIUM
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Bis(η5-indenyl)dicarbonyltitanium has been produced in 47percent yield by reduction of bis(η5-indenyl)dichlorotitanium with activated aluminum in THF solution under a carbon monoxide atmosphere.Bis(η5-indenyl)dicarbonylzirconium can similarly be prepared in 45 percent yield by the reductive carbonylation of bis(η5-indenyl)dichlorozirconium using activated magnesium turnings.IR spectral evidence has been obtained for the corresponding hafnium analog, although it could not be isolated.Detailed syntheses for the precursors (η5-indenyl)2MCl2 (M = Ti, Zr, Hf) have been developed.Bis(η5-indenyl)dicarbonyltitanium crystallizes in the monoclinic space group C2/c with unit cell parameters a 30.435(8), b 7.357(5), c 28.279(8) Angstroem and β 90.93(5) deg.Refinement of 3530 observed reflections lead to final agreement indices of R = 0.052 and Rw = 0.049.Bis(η5-indenyl)dicarbonylzirconium crystallizes in the monoclinic space group P21/n with unit cell parameters of a 7.288(5), b 14.398(8), c 15.273(7) Angstroem and β 89.84(5) deg.Refinement of 2253 observed reflections lead to final agreement indices of R = 0.049 and Rw = 0.055.
- Rausch, Marvin D.,Moriarty, Kevin J.,Atwood, Jerry L.,Hunter, William E.,Samuel, Edmond
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