Crystal structure of enantiomerically pure bis(dimethylbicyclooctylcyclopentadienyl) zirconium dichloride

Halterman, Ronald L.; Chen, Zhouliang

doi:10.1016/0022-328x(95)05538-z

Cited by 7 publications

(1 citation statement)

References 15 publications

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“…The seven-membered rings of the hexahydroazulenyl ligands lie on opposite sides, as well as the benzyl groups. The distances and angles around the Zr1 atom (Table ) are similar to those found in other (RCp) 2 ZrCl 2 unbridged metallocenes with bulky R groups and in unbridged (Ind) 2 ZrCl 2 indenyl derivatives, , but both the Cl−Zr−Cl and Cp−Zr−Cp angles are a bit larger than those reported for other “fluxional catalysts”, suggesting the presence of a more “open” catalytic center.…”

Section: Resultssupporting

confidence: 73%

Unbridged Zirconium and Titanium Metallocenes with Seven- or Eight-Saturated Fused-Ring Ligands: a Route for the Synthesis of Stereoblock Polypropene

Losio¹,

Zecchi²,

Bertini³

et al. 2005

Macromolecules

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Unbridged zirconocene catalysts, where a seven-or eight-membered ring fused to a cyclopentadiene is associated with a phenyl substituent in position 2 (C 7Ph-Zr and C8Ph-Zr), were tested, under the same polymerization conditions, to produce polypropenes with microstructure, molecular properties, and thermal behavior similar to those prepared with (IndPh)2ZrCl2 (w-Zr), the "classical" Waymouth catalyst. Different results were obtained from the homologue titanium catalysts (C7Ph-Ti and C8Ph-Ti) and from the titanium benzyl derivative (C7Bn-Ti), which produced quite heterogeneous materials with broad molecular weight and that can be separated into fractions spanning from completely atactic to fractions characterized by the presence of long isotactic blocks. A quite interesting behavior is observed with the zirconium benzyl derivative C7Bn-Zr, which produces good yields of a polymer with narrow polydispersity, which, despite its rather high isotacticity, shows a hardly detectable melting peak and is completely ether soluble. Quite surprisingly, the same sample, after prolonged annealing, shows a narrow melting peak at low temperature (55-65 °C). This result, together with the X-ray analysis, is in favor of a quite homogeneous material, capable of giving crystallites of small size.

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Section: Resultssupporting

confidence: 73%

Unbridged Zirconium and Titanium Metallocenes with Seven- or Eight-Saturated Fused-Ring Ligands: a Route for the Synthesis of Stereoblock Polypropene

Losio¹,

Zecchi²,

Bertini³

et al. 2005

Macromolecules

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Complexes of Zirconium and Hafnium in Oxidation State iv

Chen

Rodríguez‐Delgado

2007

Comprehensive Organometallic Chemistry III

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Preparation of [2,5-Diisopropylcyclohexane-1,4- bis(indenyl)]titanium Dichloride and [2,5-Diisopropylcyclohexane-1,4-bis(tetrahydroindenyl)]- titanium Dichloride and Their Comparison as Catalysts for the Enantioselective Pinacol Coupling of Benzaldehyde

et al. 2000

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The nonracemic bis(indene) (+)-(1R,2R,4R,5R)-1,4-bis(3′-indenyl)-2,5-diisopropylcyclohexane (10) was synthesized in 60% yield from the addition of indenyllithium to the corresponding bis(methanesulfonate) ester of 2,4-diisopropyl-1,4-cyclohexanediol. Deprotonation of bis(indene) 10 with n-BuLi followed by metalation with TiCl 3 and oxidative workup (HCl, air, chloroform) gave the single stereoisomeric 2,5-diisopropylcyclohexane-1,4-diylbridged bis(indenyl)titanium dichloride 3 in 80% yield. Attempts to form the corresponding bis(indenyl)zirconium dichloride were unsuccessful. Catalytic hydrogenation of bis(indenyl)titanium dichloride 3 gave the 2,5-diisopropylcyclohexane-1,4-diyl-bridged bis(tetrahydroindenyl)titanium dichloride 4 in 76% yield. The solid-state structure of 4 was determined by X-ray crystallographic methods. Nonracemic mixtures of chiral bis(indenyl)titanium dichloride 3 and bis(tetrahydroindenyl)titanium dichloride 4 were examined as catalysts for the pinacol coupling of benzaldehyde in the presence of manganese metal. The enantioselectivities for dihydrobenzoin were 0% with bis(indenyl) 3 and 32% with bis(tetrahydroindenyl) 4 to give the first comparison of enantioselectivities with corresponding bis(indenyl) and bis-(tetrahydroindenyl) complexes. Scheme 1 Scheme 2

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Crystal structure of enantiomerically pure bis(dimethylbicyclooctylcyclopentadienyl) zirconium dichloride

Cited by 7 publications

References 15 publications

Unbridged Zirconium and Titanium Metallocenes with Seven- or Eight-Saturated Fused-Ring Ligands: a Route for the Synthesis of Stereoblock Polypropene

Unbridged Zirconium and Titanium Metallocenes with Seven- or Eight-Saturated Fused-Ring Ligands: a Route for the Synthesis of Stereoblock Polypropene

Complexes of Zirconium and Hafnium in Oxidation State iv

Preparation of [2,5-Diisopropylcyclohexane-1,4- bis(indenyl)]titanium Dichloride and [2,5-Diisopropylcyclohexane-1,4-bis(tetrahydroindenyl)]- titanium Dichloride and Their Comparison as Catalysts for the Enantioselective Pinacol Coupling of Benzaldehyde

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